1TR One True Recovery; booting into macOS recovery on Apple Silicon by holding the power button to verify physical presence; enables interaction with SEP to change Boot Policy
AA Apple account
AA Apple Account
AA Apple Archive, see also Apple Encrypted Archive; command line tools: aa, aea, compression_tool
AAC Automatic Assessment Configuration; AutomaticAssessmentConfiguration.framework; puts device in a locked mode for exam-style test applications
AAT Apple Advanced Typography; font format and rendering engine
ACDE Apple Connect Device External? ACDEClient.framework, old two-step verification, derived from a company-internal AppleConnect system?
ACFS Apple Clustered File System; deprecated file system for Xsan; acfs.framework
Acoustic ID Siri feature to recognize songs
Acoustic ID song recognition and matching with Apple catalog, playback on HomePod; /System/Library/Components/AudioDSP.component
Activation cryptographic check-in with iCloud to lock devices reported by the user as lost; verified by iBoot; MobileActivationMacOS.framework; launchd service: com.apple.mobileactivationd; servers: humb.apple.com, albert.apple.com
Activity jobs, coarse-grained work units of applications; tracked by the system across XPC, bears a QoS class for scheduling; low-level mechanism not to be confused with User Activity
AE Apple Events; messaging system to invoke application functionality; CoreServices.framework/AE.framework; launchd services: com.apple.coreservices.appleevents, com.apple.AEServer (AE over network)
Aegir astronomy watch face and lock screen; /System/Library/CoreServices/AegirProxyApp.app
AFM Apple Foundation Model; pre-trained transformer and diffusion models for Greymatter, optimized for on-device use by quantization (with accuracy-recovery adapters) and palletization; command line tool: modelcatalogdump
AGC Apple Graphics Control, management of multiple displays and display port connections; launchd service: com.apple.displaypolicyd
AHAP Apple Haptic Audio Pattern; file format for simultaneous audio and haptic data; CoreHaptics.framework
AIR Apple Intermediate Representation; synthetic bytecode architecture target for GPU binary toolchain
ALF Application-Layer Firewall; implemented as a Network Extension (see System Extension); launchd service: com.apple.alf (socketfilterfw); command line tool: socketfilterfw
Alloy substrate for communication between user devices over Bluetooth and devices to iCloud, implemented over IDS; /System/Library/IdentityServices/ServiceDefinitions; launchd service: com.apple.identityservicesd
ALS Ambient Light Sensor, AmbientDisplay.framework
Amber Swift UI; SwiftUI.framework
AMFI Apple Mobile File Integrity, checks code integrity based on code signature, stronger enforcement with hardened runtime, validates entitlement restrictions; launchd service: com.apple.MobileFileIntegrity (amfid, invoked by kernel through host special port 18); disabled by setting amfi_get_out_of_my_way=0x1 in boot-args
AMFI Apple Mobile File Integrity, checks code integrity based on code signature, stronger enforcement with hardened runtime, validates entitlement restrictions and environment constraints (launch constraints, library constraints); launchd service: com.apple.MobileFileIntegrity (amfid, invoked by kernel through host special port 18); disabled by setting amfi_get_out_of_my_way=0x1 in boot-args
AMP Apple Media Protocol? former parts of iTunes for iPod and iOS device access in Finder, Home Sharing; AMPDevices.framework, AMPSharing.framework; launchd services: com.apple.AMPDeviceDiscoveryAgent, com.apple.AMPDevicesAgent, com.apple.amp.mediasharingd
AMP Asynchronous Multiprocessing; performance and power-efficiency cores on Apple Silicon
AMS Apple Media Services; formerly the iTunes stores and media services: App Stores, Apple Music, Apple TV, iCloud media library, Apple Podcasts, Podcast sync, Books Store, Books sync; AppleMediaServices.framework; server: phobos.apple.com
@@ -30,31 +32,32 @@ AOP Always On Processor, part of Apple SoCs, runs RTKit as operating system
AOS Apple Online Services? historical name for iCloud
Apache built-in web server; command line tool: apachectl
APFS Apple File System; copy-on-write file system with support for volume space-sharing, per-file encryption, and snapshots
APNS Apple Push Notification service, server infrastructure for remote push notifications over a single connection, clients subscribe to push topics, can be authenticated by app (remote notifications), device (Find My …), or Apple ID login (DSID); credentials in apsd keychain; launchd service: com.apple.apsd; server: push.apple.com
APNS Apple Push Notification service, server infrastructure for remote push notifications over a single connection, clients subscribe to push topics, can be authenticated by app (remote notifications), device (Find My …), or Apple Account login (DSID); credentials in apsd keychain; launchd service: com.apple.apsd; server: push.apple.com
App Nap quiescence detection for applications and corresponding self-demotion in scheduler parameters, implemented within application frameworks and RunningBoard, listens for occlusion notifications from WindowServer
App Sandbox Seatbelt-based sandbox for apps; /System/Library/Sandbox/Profiles/application.sb; enabled with com.apple.security.app-sandbox entitlement; launchd service: com.apple.secinitd
APT Adaptive Picture Timing? ProMotion; dynamic screen updates with 120Hz base frequency; AppleDisplayTCONControl.framework
Ask To parental-controlled user can ask parent for exceptions; launchd service: com.apple.asktod; AskTo.framework
ASL Apple System Logger, superseded by Unified Logging; /etc/asl; stored in /var/log/asl; launchd service: com.apple.syslogd; command line tool: syslog
ASR Apple Software Restore; restore entire volumes from sources like disk images (HDI, SIU), also restores based on APFS snapshots and snapshot deltas; command line tool: asr
Assertions power state management allowing applications to prevent sleeping; launchd service: com.apple.powerd; command line tools: caffeinate, pmset
Assessment checking of System Policy; term also used for AAC
Asset Cache discretionary caching server for Mobile Assets, Packages, iOS updates, App Store content, ODR, MMCS data; launchd services: com.apple.AssetCache.builtin, com.apple.AssetCacheLocatorService, com.apple.AssetCacheManagerService, com.apple.AssetCacheTetheratorService; command line tools: AssetCacheLocatorUtil, AssetCacheManagerUtil, AssetCacheTetheratorUtil
Assistant Siri; dictation and semantic understanding, Intent is communicated to and enacted on the client, uses TTS for output, Snippets to embed mini UIs into responses; /System/Library/Assistant, /System/Library/Snippets, AssistantServices.framework; server: *.siri.apple.com
Assistant Siri; speech recognition and semantic understanding, dialog management by CDM, Intent is communicated to and enacted on the client, uses TTS for speech output, Snippets to embed mini UIs into responses; /System/Library/Assistant, /System/Library/Snippets, AssistantServices.framework; server: *.siri.apple.com
ATS App Transport Security, sandbox mechanism only allowing TLS-secured connections
ATSUI Apple Type Services for Unicode Imaging; rendering engine superseded by CoreText.framework, font management; ApplicationServices.framework/ATS.framework; launchd service: com.apple.xtyped (fontd); command line tools: atsutil
ATT App Tracking Transparency; apps declare user tracking on app store
Attestation cryptographic proof of a genuine SEP; used for web authentication and app attestation; DeviceCheck.framework; SEP responds to challenge using hardware-key (GID, PKA), online service verifies; used to pair Touch ID keyboards, used to pair RemoteXPC channel?
Authorization discretionary access control policies for high-level services; similar to PAM; policy stored in /var/db/auth.db
Avatar Memoji and Animoji, including pre-rendered iMessage stickers; AvatarKit.framework
AVB Audio Video Bridging, low-latency audio over Ethernet; launchd service: com.apple.avbdeviced; command line tool: avbdiagnose, avbutil
AWD Apple Wireless Diagnostics, sends system telemetry to Apple; CoreAnalytics.framework, WirelessDiagnostics.framework; launchd services: com.apple.awdd, com.apple.analyticsd
AVB Audio Video Bridging, low-latency audio over Ethernet; launchd service: com.apple.avbdeviced; command line tools: avbanalyse, avbdiagnose, avbutil
AWD Apple Wireless Diagnostics, sends system telemetry to Apple; CoreAnalytics.framework, WirelessDiagnostics.framework; launchd services: com.apple.analyticsd
AWDL Apple Wireless Direct Link; secondary WiFi interface that runs in parallel to an active WiFi access point connection, similar to WiFi Direct (p2p interface), uses a randomized MAC, used for peer-to-peer networking: AirDrop, AirPlay; DeviceToDeviceManager.framework
Background Assets assets that an app extension loads without the app being launched; BackgroundAssets.framework; extension point: com.apple.background-asset-downloader-extension; launchd service: com.apple.backgroundassets.user
Background Assets assets that an app extension loads without the app being launched; BackgroundAssets.framework; launchd service: com.apple.backgroundassets.user
Bezel on-screen overlays for hardware volume buttons, screen brightness, Bluetooth HID, and others; /Library/Application Support/Apple/BezelServices, launchd services: com.apple.loginwindow, com.apple.OSDUIHelper
Blast Door sandboxed sanitization process for untrusted iMessage input; BlastDoor.framework
Biome CloudKit-synced streaming and storage of events like donated and invoked Intents; semantic index to ground AI with personal context; BiomeStreams.framework, BiomeSync.framework; launchd services: com.apple.BiomeAgent, com.apple.biomesyncd; embedding vector extraction and storage: ZeoliteFramework.framework
Blast Door sandboxed sanitization process for untrusted input, used for iMessage, IDS, Telephony, media analysis; BlastDoor.framework, CTBlastDoorSupport.framework, IDSBlastDoorSupport.framework, MediaAnalysisBlastDoorSupport.framework, MessagesBlastDoorSupport.framework, TelephonyBlastDoorSupport.framework
BOM Bill of Materials; format to store contents of installer Packages; command line tool: lsbom
Bonjour mDNS; launchd service: com.apple.mDNSResponder.reloaded; command line tool: dns-sd
Boot Cache disk cache pre-heating at boot time with typically loaded applications; /var/db/BootCaches; launchd service: com.apple.warmd
@@ -66,24 +69,30 @@ Bulletin Board application push notification management, aggregates local and re
Cache Delete cleanup for various caches; /System/Library/CacheDelete; launchd service: com.apple.cache_delete (deleted)
CAML Core Animation Markup Language; XML file format for layers, shapes and animations
Carousel derivative of SpringBoard for Watch home screen, watch face, and notification center
Celestial media streaming used by ReplayKit for game broadcasts; Celestial.framework
CDHash Code Directory Hash; a hash of hashes over the parts of a code bundle; command line tool: codesign
CDM Continuous Dialog Manager; natural dialog with Siri, MARRS for multi-modality; ContinuousDialogManagerService.framework
CEC Consumer Electronics Control; remote control for HDMI-connected devices; CoreRC.framework, IOCEC.framework
Celestial media streaming used by ReplayKit for in-app screen broadcasts; Celestial.framework; launchd service: com.apple.replayd
Certificates validity checked using CRLs, OCSP stapling, and transparency logs; /System/Library/Security/Certificates.bundle; launchd services: com.apple.trustd, com.apple.trustd.agent, com.apple.ocspd; command line tool: crlrefresh
Chamois Stage Manager
CHIP Connected Home over IP; Matter; integrated into HomeKit; CHIPPlugin.framework
CHIP Connected Home over IP; Matter; integrated into HomeKit, can use Thread as transport layer; HomeKitMatter.framework, CoreThread.framework; launchd services: com.apple.threadradiod, com.apple.ThreadCommissionerService
Circle cryptographic primitive to exchange public keys of trusted devices of a user, signed by Circle peers; iCloud identity added as additional Circle peer, private key synced across all trusted devices, new devices can pull this key from Secure Backup to join the Circle; per-device Circles stored in CKKS for two-factor accounts (Octagon); KeychainCircle.framework; command line tools: otctl (Octagon)
CKKS CloudKit Key Sync, end-to-end secure syncing for credentials, seeded by Circle; currently includes ApplePay, AutoUnlock, CreditCards, DevicePairing, Engram, Health, Home, Manatee, SOS, WiFi and other keys; launchd service: com.apple.secd; command line tool: ckksctl
CL4 Apple’s variant of the L4 microkernel, derived from Pistachio/seL4 and Wombat/Darbat
Clarity customizable accessibility mode for simplified UI; ClarityFoundation.framework
Classroom school teachers can create assignments for student iPads and track progress in Schoolwork app; ClassKit.framework; launchd service: com.apple.studentd
Cloud Pairing part of Alloy, Bluetooth out-of-band pairing over iCloud for Continuity; launchd service: com.apple.BTServer.cloudpairing (cloudpaird)
CMAS Commerial Mobile Alert System, now known as Wireless Emergency Alerts (WEA)
Commpage user-mapped kernel data, like vdso/vsyscall on Linux; mapped at 0x7fffffe00000
Companion iPhone that is paired with Watch; communication uses Alloy over IPsec over Bluetooth
Continuity umbrella term for Handoff, Sidecar, SMS relay, Universal Clipboard, Watch unlock, WiFi call relay and others; SMS relay works by proxying to iMessage, other services use Alloy
Companion iPhone that is linked with Watch, Mac, or Apple TV; communication with Watch uses Alloy over IPsec over Bluetooth, AWDL on demand; launchd service: com.apple.companiond; Bonjour service: _companion-link._tcp
Contact Key Verification code for manual verification of iMessage keys; code identifies a long-lived account key stored in iCloud Keychain, which signs all ESS device keys
Continuity umbrella term for Handoff, Sidecar, iPhone Mirroring, SMS relay, Universal Clipboard, Watch unlock, WiFi call relay and others; SMS relay works by proxying to iMessage, other services use Alloy for signalling and AWDL for payload; /System/Applications/iPhone Mirroring.app, ScreenContinuityServices.framework
Control Center icons in menu/status bar and Bento Box controls UI, gradually replaces SystemUIServer on macOS; handles incoming AirPlay content; launchd services: com.apple.controlcenter, com.apple.SystemUIServer.agent
Cryptex Cryptographically sealed Extension of SSV, mount-invisible extension of the root volume, allows lightweight updates as part of Rapid Security Response; /System/Cryptexes (mountpoint), /System/Volumes/Preboot/*/cryptex1/current/*.dmg (disk images)
Cryptex Cryptographically sealed Extension of SSV, mount-invisible overlay of the root volume, allows lightweight updates as part of Rapid Security Response; /System/Cryptexes (mountpoint), /System/Volumes/Preboot/*/cryptex1/current/*.dmg (disk images)
CSR Configurable Security Restrictions; XNU subsystem that is the basis for SIP
CTK Crypto Token Kit; smart card management, also for the Secure Element on iOS? launchd service: com.apple.ctkd; command line tool: sc_auth
CTS Centralized Task Scheduling; execution of DAS tasks; /System/Library/UserEventPlugins/com.apple.cts.plugin
@@ -91,6 +100,7 @@ CVMS Core VM Server/Service? compilation of GPU shaders; launchd service: com.ap
DAAP Digital Audio Access Protocol; used by Home Sharing (with Rapport token) and by the Remote app to control Apple TV (with pairing token); payload unencrypted; DAAPKit.framework; Bonjour services: _atc._tcp, _home-sharing._tcp, _mediaremotetv._tcp, _touch-able._tcp
Daily Briefing Siri giving an overview of information for the day; SiriDailyBriefingInternal.framework
DART DMA Address Relocation Table; IOMMU implementation in Apple silicon, positioned in front of every DMA-capable co-processor and peripheral, offers sub-page protection; SART: streaming variant for high-throughput devices (like NVMe)
Darwin Directory static store for users and groups, saves Open Directory interaction for the local case? /usr/lib/system/libsystem_darwindirectory.dylib, /System/Library/DarwinDirectory, /private/var/db/DarwinDirectory; command line tool: dddiagnose
DAS Duet Activity Scheduler; scheduling policy engine behind NSBackgroundActivityScheduler and XPC activities; /System/Library/DuetActivityScheduler; launchd service: com.apple.dasd
Data Detectors text analysis to highlight phone numbers, street addresses, and the like; DataDetectors.framework
Data Vault directories with the UF_DATAVAULT special flag; CSR limits access to one application
@@ -103,74 +113,87 @@ DFR Dynamic Function Row?, TouchBar; /System/Library/CoreServices/ControlStrip.a
DFU Device Firmware Update; special boot mode where iOS has not booted and the system can be installed over the Lightning connection
Differential Privacy crowdsourcing without user tracking; privacy budget for management of anonymity set; used for keyboard words, emoji, Spotlight searches, Parsec deep links, HealthKit usage, Safari telemetry; /System/Library/DifferentialPrivacy; stored in /var/db/DifferentialPrivacy; launchd service: com.apple.dprivacyd
Digital Separation safety check feature to inhibit sharing relationships; DigitalSeparation.framework
DMC Device Management Client; part of MDM; DMCApps.framework, DMCUtilities.framework
DMC Disk Mount Conditioner; simulates slow IO devices; command line tool: dmc
DND Do Not Disturb
Dose ambient sound level checking on Watch; /Applications/Dose.app
DSID Destination Signaling Identifier, unique ID for IDS login on a specific device
Duet telemetry collection engine for system and user events, forecasting by machine learning, backend for DAS, Proactive, Relevance, Screen Time, thermal and battery management; /System/Library/DuetKnowledgeBase; CoreDuet.framework, CoreKnowledge.framework, CorePrediction.framework; launchd services: com.apple.coreduetd, com.apple.knowledge-agent, com.apple.ospredictiond
Duet telemetry collection engine for system and user events, forecasting by machine learning, backend for DAS, Proactive, Relevance, Screen Time, thermal and battery management; /System/Library/DuetKnowledgeBase, /System/Library/DuetExpertCenter; CoreDuet.framework, CoreKnowledge.framework, CorePrediction.framework, CascadeEngine.framework (link to Biome); launchd services: com.apple.coreduetd, com.apple.duetexpertd, com.apple.knowledge-agent, com.apple.ospredictiond
Dyld Shared Cache dynamic linker cache, stores all system libraries in prelinked form, original library files are removed; /System/Volumes/Preboot/Cryptexes/OS/System/Library/dyld; command line tools: dyld_info, dyld_usage, update_dyld_shared_cache
EAS Exchange Active Sync; network protocol for accessing Microsoft Exchange servers
Ecosystem tracks usage of system functionalty by apps, can inform user to trigger responses; Ecosystem.framework; launchd services: com.apple.ecosystemd, com.apple.ecosystemagent
EDR Extended Dynamic Range; rendering with transfer function extending beyond sRGB white; implemented natively on XDR displays and by backlight modulation on others; HDRProcessing.framework
Energy Impact unitless metric for per-application energy consumption, machine-specific coefficients; /usr/share/pmenergy, /usr/share/kpep; launchd services: com.apple.sysmond, com.apple.thermald; command line tool: powermetrics
Energy Impact unitless metric for per-application energy consumption, machine-specific coefficients; /usr/share/pmenergy, launchd services: com.apple.sysmond, com.apple.thermald; command line tool: powermetrics
Engram Messages in iCloud; devices store received iMessages in CloudKit; Engram.framework
Entitlements capability-like attributes bound to executables by code signing; some entitlements like App Sandbox restrict ambient authority, some gradually relieve those restrictions (using Seatbelt), some services or system calls grant privilege based on caller entitlements
ESS IDS user directory, public key distribution for iMessage and CloudKit sharing, uses Transparency; server: *.ess.apple.com; launchd service: com.apple.identityservicesd
Exclave user-level portions of kernel or SEP services, used for paravirtualized access by VMs; /usr/libexec/init_exclavekit
Eye Relief screen distance warning for handheld devices; /Applications/EyeReliefUI.app
FaceTime video calls, employs the ICE (establishing peer-to-peer connection), STUN (session credential exchange) and SRTP (encrypted media streaming) protocols; FTServices.framework; launchd services: com.apple.videoconference.camera (avconferenced)
FairPlay DRM system used by app and media stores; CoreADI.framework, CoreFP.framework, CoreLSKD.framework; launchd services: com.apple.adid, com.apple.fairplayd (invoked by kernel through host special port 17), com.apple.lskdd; credentials stored in /var/db/fpsd
Family Circle Family Sharing; launchd services: com.apple.familycircled, com.apple.askpermissiond
FDE Full Disk Encryption, FileVault; command line tool: fdesetup, sysadminctl
FDR Factory Data/Device Reset? ensures that no downgrades are performed? servers: skl.apple.com, gg.apple.com; /System/Library/FDR
Feldspar Apple News; Silex.framework
FiDES Fi? Distributed Evaluation Service? aggregates Differential Privacy data for unlinkability? maybe private federated learning? used for emoji, Suggestions, Dictation; /System/Library/DistributedEvaluation; DistributedEvaluation.framework; server: fides-pol.apple.com
FiDES Fi? Distributed Evaluation Service? aggregates Differential Privacy data for unlinkability? used for emoji, Suggestions, Dictation; /System/Library/DistributedEvaluation; DistributedEvaluation.framework, FedStats.framework (private federated learning?)
File Provider infrastructure and extension system for syncing with cloud providers; placeholder files based on SF_DATALESS attribute in APFS; FileProvider.framework; locally stored in ~/Library/CloudStorage; command line tool: fileproviderctl
Find My … location sharing by explicitly querying devices remotely or collateral beacon detection using Search Party; FMCore.framework, FMF.framework; launchd service: com.apple.icloud.fmfd (find my friends)
Find My location sharing by explicitly querying devices remotely or collateral beacon detection using Search Party; FMCore.framework, FMF.framework
Firmlink bi-directional non-symbolic link between the read-only system volume and the data volume, additional symlinks and mountpoints in the root directory are virtually allocated; /usr/share/firmlinks, /etc/synthetic.conf
Focus restriction modes for notification presentation; focus filters for in-app display restrictions, communicat by Intents; Focus.framework, DoNotDisturb.framework; local settings in ~/Library/DoNotDisturb
Focus restriction modes for notification presentation; focus filters for in-app display restrictions, communicated by Intents; Focus.framework, DoNotDisturb.framework; local settings in ~/Library/DoNotDisturb
FollowUp user interaction for Secure Backup wrapping with device passcode, CoreFollowUp.framework; launchd service: com.apple.followupd
FoundationDB fundamental iCloud storage database, marketed as CloudKit, separated into containers; records, blobs, and large asset storage with MMCS, server-side continuous queries can trigger push notifications, user management by IDS, sharing between users; PCS keys used for hierarchical zone, record, and asset encryption; CloudKitDaemon.framework; launchd service: com.apple.cloudd; locally stored in ~/Library/Caches/CloudKit, ~/Library/Containers/*/Data/CloudKit; command line tool: cktool
FPR Fast Permission Restrictions; Apple CPU registers to downgrade (old APRRs do bitmasking) or remap (SPRRs since M1) actual permissions of memory pages (the CTRR region) per thread; used for JIT protection and by AMFI to freeze user code after checking
FUD Firmware Update Daemon; /var/db/fud; launchd service: com.apple.accessoryupdaterd
FoundationDB fundamental iCloud storage database, marketed as CloudKit, separated into containers; records, blobs, and large asset storage with MMCS, server-side continuous queries can trigger push notifications, user management by IDS, sharing between users by GroupKit; PCS keys used for hierarchical zone, record, and asset encryption; CloudKitDaemon.framework; launchd service: com.apple.cloudd; locally stored in ~/Library/Caches/CloudKit, ~/Library/Containers/*/Data/CloudKit; command line tool: cktool
FPR Fast Permission Restrictions; Apple CPU registers to downgrade (old APRRs do bitmasking) or remap (SPRRs since M1) actual permissions of memory pages (the CTRR region) per thread
FRC Flow Residual Correction? optical-flow video analysis; FRC.framework
FSKit user space file system support; kernel stub file system is /System/Library/Extensions/lifs.kext; file systems are in /System/Library/ExtensionKit/Extensions/com.apple.fskit.*; launchd service: com.apple.filesystems.fskitd, com.apple.filesystems.doubleagentd (handling of Apple double files in user space); extension point: com.apple.fskit.fsmodule
FUD Firmware Update Daemon; see TSS, UARP; launchd service: com.apple.accessoryupdaterd
Game Mode auto-activates when games are shown full screen, throttles background work, lowers audio and input latency; launchd service: com.apple.gamepolicyd
GID group ID key, shared across all devices of the same SoC generation, derived keys are used to prove device type over the network, only accessible by SEP
Gizmo Apple Watch; watch settings managed by Companion; /Applications/Bridge.app, /System/Library/BridgeManifests
Gizmo Apple Watch; watch settings managed by Companion iPhone; /Applications/Bridge.app, /System/Library/BridgeManifests
Greymatter Apple Intelligence; on-device language and diffusion models, larger server-based models in PCC; AFM refined for specific tasks (queries, summarization, categorization) by adapters (parameter for inserted network modules); grounded with context from Biome and intelligence stores; ~/Library/IntelligencePlatform; launchd service: com.apple.modelmanagerd (model residency management); /System/Library/ModelManager/Policy.plist; /Applications/Tamale.app (Camera Control integration); command line tool: csfdiagnose (cloud subscription features), modelmanagerdump
Group Activities SharePlay; sharing of media content and programmatic state over FaceTime calls; GroupActivities.framework, CopresenceCore.framework; launchd service: com.apple.telephonyutilities.callservicesd
GroupKit groups of IDS users with shared CloudKit (PCS) access; GroupKitCrypto.framework
GSS Generic Security Service; part of Kerberos; GSS.framework; launchd service: com.apple.gssd (invoked by kernel through host special port 19); command line tool: gsstool
GXF Guarded Execution Feature/Fault, additional exception levels on Apple Silicon, lateral to the usual exception levels; page tables remain the same, but interpretation of permission bits changes by way of FPR, genter and gexit instructions; implements lightweight intra-address-space protection contexts
HAP Home Automation Protocol; CoreHAP.framework
HDA High Definition Audio; HDAInterface.framework
HDI Hard Disk Image; command line tool: hdiutil
HeadBoard derivative of SpringBoard for tvOS home screen; /Applications/HeadBoard.app, /Applications/PineBoard.app
Health Balance vitals app on Watch; /Applications/NanoHealthBalance.app
HLS HTTP Live Streaming
HomeEnergy HomeKit management for grid energy supply; EnergyKit.framework
HSA Hardware Security Architecture; version 1 used for two-step verification, SOS with iCSC; version 2 for two-factor authentication, CKKS and Secure Backup with iCDP
HSM Hardware Security Module; HSM fleet runs escrow service for Secure Backup
iBoot boot loader stage after boot ROM or UEFI (macOS on Intel); intermediate Low-Level Bootloader (LLB); DFU mode is implemented here; /System/Library/CoreServices/boot.efi
iCDP iCloud Data Protection, codename for a set of enhancements to iCloud privacy: device passcodes used as iCSC for Secure Backup, root keys for CKKS-enabled services only synced between devices and not stored at Apple; launchd service: com.apple.cdpd
iCloud umbrella term for a conglomerate of services, consists of FoundationDB containers with PCS views for key management, supported by CKKS; uses IDS and APNS; some services under the iCloud name are actually served by AMS, IMAP, or DAV
iCSC iCloud Security Code, credential wrapping for Secure Backup, previously used a separate code, with HSA2/iCDP uses device passcodes
IDAM Inter-Device Audio and MIDI; audio connection between devices
IDS Identity Service, also IDMS, Apple ID identity management for all of Apple’s online services; APNS topics for signaling and messaging, see also Alloy, ESS, FaceTime, iMessage; authentication to services with Kerberos
IDS Identity Directory Service, also IDMS, Apple Account identity management for all of Apple’s online services; APNS topics for signaling and messaging, see also Alloy, ESS, FaceTime, iMessage; authentication to services with Kerberos
IDV Identity Verification? Touch ID and Face ID; /System/Library/AccessibilityBundles/CoreIDVUI.axbundle
IM Instant Messaging; usually means iMessage and FaceTime
IMG4 boot files (Mach-O binaries or configuration data) with ASN.1 signature, contains RemotePolicy certificate constraints to restrict Boot Policy evaluation
Intent use-case-driven interaction with 3rd-party apps from a host app; used for Siri, Maps, Shortcuts, Widgets (configuration); definition file or programmatically using AppIntents.framework; command line tool: appintentsmetadataprocessor (Xcode extracts Intent definition at compile time); extension points: com.apple.intents-service, com.apple.intents-ui-service
Intent semantic interaction between app and system (or another app); used for Siri, Shortcuts, Maps (contextual suggestion), Widgets (configuration); definition by file or programmatically using AppIntents.framework; command line tool: appintentsmetadataprocessor (Xcode extracts Intent definition at compile time); extension points: com.apple.intents-service, com.apple.intents-ui-service
IOKit device driver subsystem for in-kernel and DriverKit drivers, command line tool: ioreg
Ironwood dictation, customized on server with selected user data (contacts, app names, music titles, HomeKit names, Siri Shortcut phrases), not tied to Apple ID; SpeechRecognitionCore.framework; server: guzzoni.apple.com
Ironwood dictation, customized on server with selected user data (contacts, app names, music titles, HomeKit names, Siri Shortcut phrases), not tied to Apple Account; SpeechRecognitionCore.framework, ASRBridge.framework; server: guzzoni.apple.com
ISP Image Signal Processor; camera imaging circuit in iPhones
ITML iTunes Markup Language; metdata tagging for media services; ITMLKit.framework
ITP Intelligent Tracking Prevention, cross-site tracking defenses in Safari, statistics and user interaction classify sites, cookies are partitioned and access is restricted
JARVIS Just A Rather Very Intelligent Scheduler, Mesos cluster manager for Siri, iCloud, AMS
Jellyfish Animoji; /Applications/Jellyfish.app
Jetsam reclaiming of purgeable memory and termination of apps during memory pressure
Journal diary app; JournalShared.framework
JSC JavaScript Core; JavaScriptCore.framework; command line tool: jsc
Kalamata codename for the transition from x86 to ARM-based Apple Silicon
Kerberos single-sign-on mechanism; Heimdal.framework; command line tools: kinit, ktutil
Kext kernel extension mechanism, loaded at boot time as part of a Kext Collection; /Library/Extensions, /Library/StagedExtensions (for user approval), /System/Library/Extensions; command line tool: kextutil (manages deprecated runtime loading)
Kext Collection prelinked sets of kernel extensions; /System/Library/KernelCollections (for boot and system kexts), /Library/KernelCollections (for auxiliary third-party kexts); the latter is only loaded at a lower-security Boot Policy; launchd service: com.apple.kernelmanagerd (invoked by kernel through host special port 15); command line tool: kmutil
Keybag storage of protection class keys for Keychain and filesystem, protected by SEP using SKP; stored in user.kb; launchd services: com.apple.mobile.keybagd, com.apple.securityd_service, com.apple.secd
Keybag storage of protection class keys for Keychain and filesystem, protected by SEP using SKP; stored in user.kb; launchd services: com.apple.mobile.keybagd, com.apple.secd
Keychain storage for credentials; launchd service: com.apple.securityd; command line tools: certtool, security, systemkeychain
KIP Kernel Integrity Protection, locking of physical memory pages to prevent changes to kernel
Launch Services management for application launches, association of UTIs to apps, uses Spotlight to update cached info; launchd services: com.apple.coreservices.launchservicesd, com.apple.lsd; CoreServices.framework/LaunchServices.framework; command line tools: lsappinfo, lsregister
Liquid Glass UI design language, includes icon treatment; IconRendering.framework, LightSourceSupport.framework
Live Files user mode filesystems, currently FAT, ExFAT, NTFS on external storage; UserFS.framework, UVFSXPCService.framework; launchd service: com.apple.filesystems.userfsd
Liverpool PCS codename for CloudKit
LKDC Local Key Distribution Center, Kerberos on client machines
@@ -178,39 +201,46 @@ LSM Latent Semantic Mapping, text analysis, used for spam filtering, command lin
Mac Buddy historic name for Setup Assistant
MAC Policy Mandatory Access Control subsystem in XNU, based on TrustedBSD, implements policy hooks for restricted kernel operations; current policies: AMFI, Seatbelt, Quarantine, CSR
Machine Learning Vision.framework, Espresso.framework, Futhark.framework, PhotoAnalysis.framework; used for Live Text and Visual Lookup; launchd service: com.apple.mediaanalysisd
Madrid iMessage; /System/Library/Messages
Madrid iMessage; /System/Library/Messages; BubbleKit.framework (message bubble UI)
Manatee PCS key for some CloudKit containers are synced via CKKS, so data is unreadable to Apple (credential management codenames: Plesio, Stingray, Cuttlefish)
Mandrake emergency siren on Apple Watch Ultra; /Applications/Mandrake.app
Mangrove transfering UI tiles over XPC; Mangrove.framework, IOSurface.framework
Marco Marco.framework, something about IDS and communication (iMessage, Calls), logging?
Marklar codename from the PowerPC era for the port to x86, served the transition to Intel CPUs
Marzipan Catalyst; port of iOS frameworks to macOS, Catalyst apps are iOS apps with additional API to adapt macOS UI idioms; /System/iOSSupport; integration using UIKit system process; launchd service: com.apple.uikitsystemapp; input remapping by /Library/Apple/Library/Bundles/InputAlternatives.bundle
MCX Managed Client for OS X, preference management for settings from configuration profiles, /Library/Managed Preferences, command line tools: mcxquery, mcxrefresh
MDM Mobile Device Management; server software to manage fleets of iOS and macOS devices; uses configuration profiles to manage preferences; ConfigurationProfiles.framework
MDS Module Directory Services, ancient part of the old security APIs (CSDA, CSSM)
MMCS MobileMe Chunk Storage, used by iCloud, splits blobs into chunks and stores them at Apple/AWS/GCP with convergent encryption (content hash as key); MMCS.framework
Mobile prefix for iOS
Mobile Assets demand-downloaded system components like fonts, dictionaries, linguistic data; stored in /System/Library/Assets; launchd services: com.apple.languageassetd (language-dependent assets), com.apple.mobileassetd; server: mesu.apple.com
Mobile Device connectivity to iOS devices over USB or WiFi (AirTrafficHost) for syning, development, and debugging; MobileDevice.framework; launchd service: com.apple.usbmuxd; Bonjour service: _apple-mobdev2._tcp
MOC Managed Object Context; Core Data object space
Mondrian photo collage arrangement in Photos.app; Mondrian.framework
Mondrian photo collage arrangement in Photos.app; Mondrian.framework, GridZero.framework
MRT Malware Removal Tool; /Library/Apple/System/Library/CoreServices/MRT.app; superseded by XProtect
Multipeer Connectivity ad-hoc networking; Bonjour for discovery; WiFi, AWDL, Bluetooth, or Ethernet as transport; optional encryption and certificate-based authentication; MultipeerConnectivity.framework
Nano prefix for watchOS
Nearby Interaction proximity-based interaction between devices; proximity measured using ultra wideband or derived from other technologies; used for Universal Control; NearbyInteraction.framework, Proximity.framework; launchd service: com.apple.nearbyd
Nearby Interaction proximity-based interaction between devices; proximity measured using ultra wideband or derived from other technologies; used for Universal Control, tapping phones for AirDrop; NearbyInteraction.framework, Proximity.framework; launchd services: com.apple.aonsensed (always-on sense daemon), com.apple.nearbyd
Nebula sleep apnea detection on watchOS; BreathingAlgorithms.framework
New Device Outreach high-level Bluetooth device pairing flow; NewDeviceOutreach.framework, NDOAPI.framework, NDOUI.framework; launchd service: com.apple.ndoagent
Newton fall detection on watchOS
NLP Natural Language Processing; NLP.framework; related to mecabra libraries, a linguistic engine for Chinese and Japanese; /usr/share/mecabra, /usr/share/tokenizer
NLU Natural Language Understanding; Greymatter Siri engine; SiriNLUTypes.framework, SiriNaturalLanguageParsing.framework
Notarization app security scan by Apple; cryptographic proof stapled to code signature, tested at launch by System Policy; for non-notarized apps sends code hash to Apple; command line tools: notarytool, altool, stapler
Noticeboard User Notifications for Software Update and App Store, Noticeboard.framework; launchd services: com.apple.noticeboard.state (nbstated), com.apple.noticeboard.agent (nbagent)
Notifications system notification bus, unrelated to the local/remote push notifications; launchd service: com.apple.notifyd, com.apple.kuncd (invoked by kernel through host special port 10); command line tool: notifyutil; complemented by framework-level notification system (CFNotification, NSNotification); launchd services: com.apple.distnoted.xpc.daemon, com.apple.distnoted.xpc.agent
NSP Network Service Proxy; per-app VPN and proxy settings, implements Private Relay; launchd service: com.apple.networkserviceproxy
OAH Rosetta; ahead-of-time compiler for Intel code on Apple Silicon, usable from Linux VMs by way of a custom binformat; /usr/libexec/rosetta
OAH Rosetta; ahead-of-time compiler for Intel code on Apple Silicon, usable from Linux VMs by way of a custom binformat; /usr/libexec/rosetta, /var/db/oah (AOT cache); launchd service: com.apple.oahd
ODR On-Demand Resources; loaded from App Store; launchd service: com.apple.appstored
Omni Search fuzzy semantic search with results recognized in images; OmniSearch.framework
Onboarding data protection splash screen shown by service-connected apps; /System/Library/OnBoardingBundles; OnBoardingKit.framework
Open Directory directory service for user, group, and machine management; plugin-based to use different backend stores (LDAP, Active Directory), local accounts in /private/var/db/dslocal; launchd service: com.apple.opendirectoryd; command line tools: dscacheutil, dscl, dsconfigad, dsconfigldap, dseditgroup, dsenableroot, dserr, dsexport, dsimport, dsmemberutil, odutil
Open Directory directory service for user, group, and machine management; plugin-based to use different backend stores (LDAP, Active Directory), local accounts in /private/var/db/dslocal, populated from /System/Library/DirectoryServices/DefaultLocalDB; launchd service: com.apple.opendirectoryd; command line tools: dscacheutil, dscl, dsconfigad, dsconfigldap, dseditgroup, dsenableroot, dserr, dsexport, dsimport, dsmemberutil, odutil
OpenBSM Open Basic Security Module; deprecated security audit subsystem; /etc/security, /var/audit; launchd service: com.apple.auditd; command line tool: audit
Opus create slide shows from photos; Slideshows.framework
OSA Open Scripting Architecture; scripting of applications from different fontend languages (currently AppleScript and JavaScript); backed by Apple Events; command line tools: osacompile, osadecompile, osalang, osascript, sdef, sdp
@@ -218,42 +248,52 @@ OTUT One-Time Unlock Token; security mechanism to allow keybag unwrapping after
PAC Pointer Authentication Codes; pointers signed in unused bits to prevent ROP attacks
Packages unit of software installation; command line tools: pkgutil, installer, softwareupdate; launchd services: com.apple.softwareupdated, com.apple.bootinstalld, com.apple.installd, com.apple.system_installd, com.apple.uninstalld; /var/db/softwareupdate, /Library/Apple/System/Library/Receipts (system), /System/Library/Receipts (read-only), /private/var/db/receipts (App Store)
Packet Filter network traffic filtering subsystem from OpenBSD; command line tool: pfctl
Parsec Spotlight web results and searching of crowdsourced User Activity deep links; server: *.smoot.apple.com; launchd services: com.apple.parsecd, com.apple.parsec-fbf (Feedback Flush to Differential Privacy)
Parsec Spotlight web results and searching of crowdsourced Intent deep links; server: *.smoot.apple.com; launchd services: com.apple.parsecd, com.apple.parsec-fbf (Feedback Flush to Differential Privacy); telemetry collection with Poirot: PoirotSQLite.framework, PoirotUDFs.framework, SearchOnDeviceAnalytics.framework
Party Studio Karaoke mode on tvOS, where video from a paired phone is shown with effects; PartyStudio.framework; /Applications/Sing.app
Passkey keypair used for authentication instead of password, synced via SOS, implements WebAuthn standard; keys can be used to login on separate device via QR code and Bluetooth proximity proof; AuthenticationServices.framework
Password Breach monitoring of Keychain passwords against a breach database; round-robin matching in fixed-size batches, local match against common leaks, remote match using hash prefix; launchd service: com.apple.Safari.passwordbreachd
Pasteboard storage for cut, copy, and paste; type of content remembered as UTI; launchd service: com.apple.pboard; command line tools: pbcopy, pbpaste
PAT Private Access Tokens; blind challenge-response authentication; Apple server attests user validity to token issuer, issuer performs blind signature, websites receiving the token cannot identify user; used for Private Relay, can replace CAPTCHAs
PCS Protected Cloud Storage; key management for separate iCloud storage compartments (PCS calls them views), each can contain FoundationDB plus bulk data stored by MMCS; see also iCDP, CKKS, Manatee; ProtectedCloudStorage.framework; /System/Library/Preferences/ProtectedCloudStorage; command line tool: pcsstatus
PCC Private Cloud Compute; server-based AFM for AI, running on Apple Silicon managed by SEP; stateless computation, PAT to authorize user, Attestation of remote code by device, measurements published in Transparency; ~/Library/PrivateCloudCompute; launchd services: com.apple.privatecloudcomputed, com.apple.swtransparencyd
PCS Protected Cloud Storage; key management for separate iCloud storage compartments (PCS calls them views), each can contain FoundationDB plus bulk data stored by MMCS; see also iCDP, CKKS, GroupKit, Manatee; ProtectedCloudStorage.framework; /System/Library/Preferences/ProtectedCloudStorage; command line tool: pcsstatus
PCSC Personal Computer Smart Card; PCSC.framework, uses CTK
PDE Print Dialog Extension; old name, not a proper Extension
Peak Power managing battery power draw; launchd service: com.apple.peakpowermanagerd; /System/Library/PPM/BatteryModels
PEC/PIR Private Encrypted Compute and Private Information Retrieval; used for parental controls for media and web; CipherML.framework; launchd service: com.apple.ciphermld
Pegasus meaning 1: picture-in-picture video playback; Pegasus.framework (iOS), PIP.framework (macOS); meaning 2: online search query engine for visual lookup; PegasusKit.framework
Pepper UI elements for Watch home screen and Chat, like Quickboard (canned replies), Animoji; PepperUICore.framework
People contacts with Apple Accounts within Group Activities and Shared With You
Persona separation of sub-user-identities, like when using a private and managed Apple account; PersonaKit.framework; ~/Library/Personas; /System/Library/UserManagement; command line tool: umtool
PHASE Physical Audio Spatialization Engine; 3D sound rendering engine; Apple devices map audio sources (even mono and stereo) to virtual speakers in a 3D sound stage, which is simulated by the physical speakers via a head-related transfer function; PHASE.framework
Piano Mover Mail Drop; bulk mail attachments transfered over PCS; not to be confused with storage for iMessage attachments, which uses a CloudKit container
Plugin Extensions, XPC services bundled with apps or frameworks, discovery by Launch Services; launchd service: com.apple.pluginkit.pkd; command line tool: pluginkit
Plugin Extensions, XPC services bundled with apps or frameworks, discovery by Launch Services; extension points listed in /System/Library/ExtensionKit/ExtensionPoints; launchd service: com.apple.pluginkit.pkd; command line tool: pluginkit
PowerUI battery management like smart charge and power save, learns from Duet and other data; PowerUI.framework; /var/db/PowerUI; launchd service: com.apple.PowerUIAgent
Preferences storage for user-configurable settings; launchd services: com.apple.cfprefsd.xpc.daemon, com.apple.cfprefsd.xpc.agent; stored in Library/Preferences, command line tool: defaults; interaction with Synced Defaults per /System/Library/DefaultsConfigurations
Preview Shell skeleton for on-device UI previews during development; /System/Library/CoreServices/PreviewShell.app; PreviewShellKit.framework, XOJIT.framework (code live patching)
Private Relay two-hop onion routing with one entry and one exit node; Apple operates entry, third-party services operate exit nodes; QUIC for payload, ODoH for DNS, approximate IP geolocation via Waldo, authentication via PAT
Proactive umbrella term for suggestions and completions based on Duet forecasting and User Activity context, also marketed as Siri features; PersonalizationPortrait.framework
Proactive umbrella term for suggestions, completions, and summarizations based on Duet forecasting, Biome, and Intent context; PersonalizationPortrait.framework, ProactiveMagicalMoments.framework, ProactiveSummarization.framework
Provenance per-file origin tracking, extended attribute com.apple.provenance stores ID into /var/db/SystemPolicyConfiguration/ExecPolicy
QoS Classes inheritable property for Activities; semantic priorities, influences scheduling parameters; initially set at user-level, priority inheritance within GCD queues and across XPC in kernel?
Quagga framework for QR and barcode decoding; Quagga.framework
Quick Action extension type for quick interaction with foreign content within a host app; extension points: com.apple.services, com.apple.ui-services
Quick Look file preview and thumbnail generation; comand line tool: qlmanage
Rapport device pairing by proximity using Alloy, with PIN entry, or using iCloud; once paired, devices can access services; used for HomeKit, HomePod, AirPlay, Home Sharing, SideCar; Rapport.framework; launchd service: com.apple.rapportd; Bonjour service: _companion-link._tcp
Rapport device pairing by proximity using Alloy, with PIN entry, or using iCloud; once paired, devices can access services; used for HomeKit, HomePod, AirPlay, Home Sharing, SideCar; Rapport.framework, ProximityAppleIDSetup.framework; launchd service: com.apple.rapportd
RCS Rich Communication Services; messaging service in mobile networks, successor to SMS; IMRCSTransfer.framework; /System/Library/Messages/PlugIns/RCS.imservice
Recents recently used items (not files) in various applications, synced with Synced Defaults; CoreRecents.framework, /System/Library/Recents; launchd service: com.apple.recentsd
Relevance Engine backend for Siri suggestions (for example of Siri Shortcuts), Widget smart stacks (also Siri watch face); consumes Duet knowledge and app-provided timelines with relevance hints; /System/Library/RelevanceEngine; launchd service: com.apple.relevanced
Relevance Engine backend for Siri suggestions (for example of Siri Shortcuts), Widget smart stacks (also Siri watch face); consumes Duet knowledge and app-provided timelines with relevance hints; /System/Library/RelevanceEngine
Remote Pairing Mobile Device pairing without wired connection; RemotePairingDevice.framework; Bonjour services: _remotepairing._tcp, _remotepairing-manual-pairing._tcp
RemoteXPC connection to a non-SoC-integrated SEP like Bridge; uses HTTP/2 over a network interface, Bridge connected over USB, secured using Attestation; RemoteServiceDiscovery.framework, TrustedAccessory.framework; launchd service: com.apple.remoted, com.apple.tracd; command line tool: remotectl
Replicator notification sync from Companion iPhone, also drives remotely displayed live activities; ReplicatorServices.framework; launchd service: com.apple.replicatord
Revisions document autosave and auto-versioning; stored in .DocumentRevisions-V100; GenerationalStorage.framework; launchd service: com.apple.revisiond
Routine frequently visited locations on iOS, interacts with Duet; launchd service: com.apple.routined
RTC Real-time Telemetry and Crash reporting; RTCReporting.framework; launchd service: com.apple.rtcreportingd
RTKit operating system used on Apple Silicon for firmware of co-processors
RTKit real-time runtime used for firmware of Apple Silicon co-processors; on top of CL4 in Apple’s cellular modem
RunningBoard runtime management of apps, paradigm: app as service process invoked by system, check-in by frameworks, handles process assertions (frontmost app, see App Nap), memory pressure (see Jetsam) and compute resources (GPU), replacement for TAL?; launchd service: com.apple.runningboardd; /System/Library/LifecyclePolicy, /System/Library/RunningBoard
Safety Monitor Check In; short-term location sharing in iMessage until a destination is reached; /Applications/SafetyMonitorApp.app
Salt & Pepper UI elements for Watch; SaltUICore.framework, PepperUICore.framework
SBPL Sandbox Profile Language; a TinyScheme-based embedded DSL for Seatbelt profiles
SCIP System Coprocessor Integrity Protection; like KIP, but for SEP, ISP, Motion coprocessor
Screen Reader VoiceOver and Braille; /System/Library/ScreenReader; ScreenReader.framework
@@ -262,17 +302,18 @@ SDB SQL Database; CoreSDB.framework, used by iCloud communication
Search Party portion of Find My service for offline devices; devices emit public part of rotating key pair via Bluetooth LE, other devices encrypt current location with this key and send to Apple, private key shared over CloudKit
Seatbelt process sandbox by filtering system calls; profiles written in SBPL; /System/Library/Sandbox/Profiles, /usr/share/sandbox; default file access policy asks for TCC confirmation before access to folders with user data (like Documents) is allowed; command line tool: sandbox-exec; launchd service: com.apple.sandboxd (invoked by kernel through host special port 14 for logging)
Secure Backup escrow part of CKKS; escrow key individually wrapped with passcodes of trusted devices, stored in HSM to prevent brute forcing, uses SRP so passcodes are not visible to iCloud, limited number of recovery attempts; protocol called Lakitu, uses FollowUp; launchd service: com.apple.SecureBackupDaemon (com.apple.sbd); CloudServices.framework
SEP Secure Enclave Processor; dedicated ARM core for security services, runs L4/Darbat-based sepOS, inline encryption to DRAM, manages AES keys in storage DMA engine, factory-paired channels to Touch ID/Face ID hardware, Secure Element, Neural Engine; SEP can use but not read UID and GID keys; credential verification performed by hardware lockbox with retry count enforcement
SEP Secure Enclave Processor; dedicated ARM core for security services, runs CL4-based sepOS, inline encryption to DRAM, manages AES keys in storage DMA engine, factory-paired channels to Touch ID/Face ID hardware, Secure Element, Neural Engine; SEP can use but not read UID and GID keys; credential verification performed by hardware lockbox with retry count enforcement
Sequoia translation; downloadable language models can run on-device; /Applications/SequoiaTranslator.app, Translation.framework
Seymour Apple Fitness+; workout videos integrated with Watch sensors; SeymourCore.framework
Seymour Apple Fitness+; workout videos integrated with Watch sensors; SeymourCore.framework, Blackbeard.framework (personalisation and workout programs)
SF Symbols scalable UI symbols; rendered with various color treatments; SFSymbols.framework
Shared File List lists of recently opened files from apps that are stored with Launch Services; command line tool: sfltool; also manages login items and app-installed background daemons
Shared With You collaboration features between apps and iMessage; content shared via iMessage is surfaced in apps (Swift Transferable protocol), content in apps can be collaboratively edited and connected to an iMessage group; collaborations are expressed by keys derived from participant device keys, padded with a number of random keys to prevent tracking of device count, a merkle tree of those keys is used to prove inclusion of a specific device to an app; SharedWithYou.framework
Sharing umbrella term for wireless proximity services: AirDrop, Continuity, Instant Hotspot, WiFi sharing; used by loginwindow for Watch unlock; Sharing.framework; launchd service: com.apple.sharingd; also serves connection sharing and remote disk
Sidecar using iPhone/iPad as Mac accessory: external camera and microphone (ContinuityCapture), camera for photos and scanning (DocumentCamera.framework), external display over low-latency WiFi (llw interface) using avconferenced encoding; SidecarCore.framework; launchd services: com.apple.sidecar-display-agent (SidecarDisplayAgent), com.apple.sidecar-relay (SidecarRelay)
Sidecar using iPhone/iPad as Mac accessory: external camera and microphone (ContinuityCapture), camera for photos and scanning (DocumentCamera.framework), iPad as display over low-latency WiFi (llw interface) using avconferenced encoding; /Applications/Sidecar.app; SidecarCore.framework; launchd services: com.apple.sidecar-display-agent (SidecarDisplayAgent), com.apple.sidecar-relay (SidecarRelay)
Signpost telemetry API to report points of interest in code; launchd service: com.apple.signpost.signpost_reporter
SIL Secure Indicator Light; microphone and camera indicator on iPads rendered in hardware
Simulator running an iOS/tvOS/watchOS personality on macOS, uses sandboxing and a separate Mach bootstrap namespace for container-like isolation; installable simulators as disk images in /Library/Developer/CoreSimulator/Images; command line tool: simctl
SIP System Integrity Protection or rootless mode; collection of kernel-level security restrictions regarding file system modification, unsigned Kexts, Taskport access, NVRAM access, DTrace; /System/Library/Sandbox/rootless.conf; command line tool: csrutil, rootless-init
Site Association signed files in .well-known directory on websites; equivalent to Entitlements for websites, associates domains with app IDs for Universal Links; command line tool: swcutil
Skywalk network subsystem in XNU, links together actual technologies (Bluetooth, WiFi, Thunderbolt) and interfaces/tunnels; transacts in nexus (for conduits) and agent (for endpoints) objects; DriverKit network drivers use Skywalk; command line tool: skywalkctl
SLC System-Level Cache, architectural feature of Apple Silicon; cache located within SoC at controllers for external DRAM, serves all compute units and stages transfers between them
Social Gaming Game Center; multiplayer gaming services on top of CloudKit, shared storage and low-latency multicast for multiplayer sessions; launchd service: com.apple.gamed
Sock Puppet Watch interaction that requires Companion device
Sock Puppet Watch interaction that requires Companion iPhone
SOS Secure Object Sync; syncing backend for iCloud Keychain, not to be confused with the emergency call feature; transferred items previously staged in Synced Defaults, for two-factor accounts in CKKS; launchd services: com.apple.secd (access to local keychain), com.apple.security.cloudkeychainproxy3 (connects to Synced Defaults), com.apple.security.keychain-circle-notification
SPI System Private Interface; /System/Library/PrivateFrameworks
Splat Update Rapid Security Response, updates to Cryptex components without system restart
SpringBoard iOS home screen; like Dock (Launchpad, Mission Control, desktop picture), Control Center, SystemUIServer (menu extras icons), loginwindow (lock screen), and WindowServer (compositor) on macOS; /System/Library/CoreServices/SpringBoard.app, /Applications/PreBoard.app, BaseBoard.framework, FrontBoard.framework, SplashBoard.framework; launchd service: com.apple.backboardd (compositor)
SPRR Shadow Permission Remap Register? feature of Apple Silicon to dynamically reintepret page permissions
SPTM Secure Page Table Monitor; code in kernel-level GXF protects page table modifications; Trusted Execution Monitor (TXM) in user-level GXF implements policy and parts of AMFI
SRP Secure Remote Password; standard cryptographic protocol for proving knowledge of a secret such that attackers cannot brute-force the secret; AppleSRP.framework
SSO Single Sign-On
SSV Signed System Volume, als called Authenticated Root Volume (ARV); macOS boots from blessed read-only APFS snapshot, merkle-tree and root-hash stored in Preboot volume; modifications require disabling root authentication with csrutil from recovery, then the live filesystem can be mounted, modified, and re-blessed; command line tools: apfs_systemsnapshot, bless, csrutil
Stark CarPlay
Stockholm Secure Element in Apple SoCs, a processor running crypto protocols on keys it protects; used for Apple Pay and Car Key; related codenames: Icefall, Warsaw
Stark CarPlay; iPhone provides video feeds for in-car displays; three layers composited by the car: remote UI (from iPhone), punch-through UI (back up camera), local UI (dashboard gauges: assets from iPhone, rendered by car, like Live Activities?), overlay UI (essential indicators); associate apps on iOS: /Applications/CarCamera.app, /Applications/Charge.app, /Applications/Climate.app, /Applications/Closures.app, /Applications/Media.app, /Applications/TirePressure.app, /Applications/Trip.app, /Applications/Vehicle.app
Stockholm Secure Element in Apple SoCs, a processor running crypto protocols on keys it protects; used for Apple Pay and Car Key; related codenames: Icefall, Warsaw; SEService.framework
Storage Management freeing up disk space by managing bulky items; UI in System Information.app; StorageManagement.framework; launchd service: com.apple.diskspaced; extension point: com.apple.storagemanagement; extends Cache Delete service
Suggestions semantic analysis of mails and websites to suggest contacts, calendar events and the like; launchd services: com.apple.suggestd, com.apple.reversetemplated; custom JavaScript parsers in /System/Library/AssetsV2/com_apple_MobileAsset_CoreSuggestions
Symbols debug symbols for backtraces; CoreSymbolication.framework; launchd services: com.apple.coresymbolicationd; command line tools: atos, symbols, symbolscache
Symptoms network diagnostics; Symptoms.framework; /var/networkd/db/netusage.sqlite; launchd service: com.apple.symptomsd (invoked by kernel through host special port 27)
Synced Defaults simple key-value store for applications, no user control over data; can use iCloud key-value backend (old) or Manatee container (new, marked as com.apple.kvs) as storage; launchd service: com.apple.syncdefaultsd; locally stored in ~/Library/SyncedPreferences
System Configuration SystemConfiguration.framework; launchd service: com.apple.configd; command line tool: scutil
System Extension system-wide components formerly implemented as insecure plugins or kexts; current extension types: DriverKit, Network, Endpoint Security, Core Media IO; /System/DriverKit, /System/Library/DriverExtensions; command line tool: systemextensionsctl; launchd services: com.apple.sysextd, com.apple.nesessionmanager, com.apple.endpointsecurity.endpointsecurityd; command line tool: eslogger
System Policy Gatekeeper; policy engine for application launches and kext loading, malware signatures from /Library/Apple/System/Library/CoreServices/XProtect.bundle; /var/db/SystemPolicy; launchd service: com.apple.security.syspolicy (invoked by kernel through host special port 29); command line tool: spctl
System Extension system-wide components formerly implemented as insecure plugins or kexts; current extension types: DriverKit, FSKit, Network, Endpoint Security, Core Media IO; /System/DriverKit, /System/Library/DriverExtensions, /Library/Preferences/com.apple.networkextension.plist; command line tool: systemextensionsctl; launchd services: com.apple.sysextd, com.apple.nesessionmanager, com.apple.endpointsecurity.endpointsecurityd; command line tool: eslogger
System Policy Gatekeeper; policy engine for application launches and kext loading, malware signatures from /Library/Apple/System/Library/CoreServices/XProtect.bundle; /var/db/SystemPolicyConfiguration; launchd service: com.apple.security.syspolicy (invoked by kernel through host special port 29); command line tool: spctl
Tailspin sampling of process stack traces; launchd service: com.apple.tailspind; command line tool: tailspin
TAL Transparent App Lifecycle; process for macOS apps started and stopped independently of the user launching and quitting app; also handles session restore across reboots; ~/Library/Saved Application State; launchd service: com.apple.talagent
Taskport Mach kernel concept for ptrace-like access to task internals; access policy implemented by daemon; launchd service: com.apple.taskgated (invoked by kernel through task special port 9); command line tool: DevToolsSecurity
TCC Transparency, Consent, and Control; user control over app access to privacy-related services (kTCCService*); TCC.framework; launchd services: com.apple.tccd, com.apple.tccd.system; command line tool: tccutil; stored in /Library/Application Support/com.apple.TCC, ~/Library/Application Support/com.apple.TCC, /var/db/locationd (for kTCCServiceLocation)
Tea component of Apple’s News, Stocks, and Weather apps, maybe interest personalization? TeaFoundation.framework, TeaDB.framework, TeaUI.framework
Template App code-less app-bundle, passed to an actual executable by LauncServices; created when adding websites in Safari to Dock/Springboard; run by /System/Volumes/Preboot/Cryptexes/App/System/Library/CoreServices/Web App.app
Time Machine automatic backup service, command line tools: tmdiagnose, tmutil
Tin Can Walkie Talkie on watchOS
Tin Can Walkie Talkie on watchOS; /Applications/TinCan.app
Tones ringtones; ToneLibrary.framework
Translocation app binary copied on launch to dedicated location; initiated by Launch Services for security (prevents path traversal for apps quarantined by System Policy) or path normalization (iOS apps do not expect to be moved, but can be moved on macOS)
Transparency un-alterable append-only log to publish information; used for for ESS keys and PCC software hashes, based on CONIKS, devices audit IDS/PCC records against logs, root hashes gossiped over iMessage to detect split-view attacks; Transparency.framework; launchd service: com.apple.transparencyd; server: init-kt.apple.com
Ubiquity iCloud Drive; codename Bladerunner, uses CloudKit; CloudDocs.framework; launchd service: com.apple.bird; locally stored in ~/Library/Mobile Documents (was supposed to move to Library/CloudStorage/iCloud Drive but this was reverted)
UID unique ID key, used as root key for cryptographic subsystems, generated during manufacturing by SEP and fused into hardware, only accessible by SEP
Unified Logging system-wide logging and Activity tracking; launchd service: com.apple.logd, com.apple.diagnosticd; command line tool: log; /dev/oslog; data stored in /var/db/diagnostics, support files in /var/db/uuidtext
USD Universal Scene Description; storage format for 3D assets; /usr/lib/usd
User Activity abstraction for deep-linking into apps with structured context (people, places); used for Universal Links (schema.org on websites), Handoff, Parsec (app links in search), Siri Shortcuts, Quick Note (context awareness), Proactive; UserActivity.framework; launchd service: com.apple.coreservices.useractivityd
Urchin Tides app on watchOS; /Applications/Urchin.app
USD Universal Scene Description; storage format for 3D assets; /usr/lib/usd; command line tools: usdcat, usdchecker, usdcrush, usdextract, usdrecord, usdtree, usdzip
User Activity abstraction for deep-linking into apps with structured context (people, places); used for Universal Links (schema.org on websites), Handoff, Parsec (app links in search), Quick Note (context awareness); now part of Intents; UserActivity.framework; launchd service: com.apple.coreservices.useractivityd
User Notifications user interface for notification center; launchd service: com.apple.usernoted
UTI Uniform Type Identifiers; system for document types; file extensions and MIME types are mapped to UTIs, UTIs form a conformance graph, apps register their UTIs with Launch Services; /System/Library/CoreServices/CoreTypes.bundle; also Apple’s hardware devices are represented as UTIs
VA Video Acceleration; AppleGVA.framework, AppleVA.framework, AppleVPA.framework
VA Video Acceleration; AppleVA.framework
VDAF Verifiable Distributed Aggregation Function; part of Differential Privacy; VDAF.framework
Viceroy video conferencing used by FaceTime and ReplayKit; ViceroyTrace.framework
Virtualisation running virtual machines on macOS; Hypervisor.framework (for basic VMs and vCPUs), Virtualization.framework (brings a robust set of device models)
VSDB volume status database; /var/db/volinfo.database; command line tool: vsdbutil
Waldo selects edge servers based on approximate location, part of Private Relay, seen in NSP
Wally private search in server-side database using homomorphic encryption; private information retrieval (PIR), private nearest neighbor search (PNNS); used for Caller ID, email logos, adult website filtering, points-of-interest lookup for photos
WFS WebDAV File Sharing; built-in file sharing with Apache; /etc/wfs; command line tool: wfsctl
Widgets content excerpt from apps; provided via a timeline of view hierarchies, configuration uses Intents; visible on home screen, lock screen, as live activities, as watch complications; WidgetKit.framework; extension point: com.apple.widgetkit-extension
Widgets content excerpt from apps; provided via a timeline of view hierarchies, configuration uses Intents; visible on home screen, lock screen, as live activities, as watch complications; WidgetKit.framework, ChronoServices.framework; extension point: com.apple.widgetkit-extension; launchd service: com.apple.chronod (timeline management and sync)
Willow HomeKit; end-to-end-encrypted communication protocol and API for IoT-accessories; pairing with SRP using code printed on device, credential sync by CKKS, transported over Alloy, remote access using Apple TV as proxy; launchd service: com.apple.homed
Workflow Shortcuts; user-programmable system-wide automation, built-in triggers cause a chain of actions to run; actions are synthesized from User Activities and Intents provided by apps; WorkflowKit.framework, ActionKit.framework; locally stored in ~/Library/Shortcuts; launchd service: com.apple.siriactionsd (voice-triggered shortcuts); command line tool: shortcuts
xART eXtended Anti-Replay Technology; persistent storage for SEP, used by Mesa; /System/Volumes/xarts; launchd service: com.apple.xartstorageremoted; command line tool: xartutil
XProtect signature-based malware scanner and remediation service; /Library/Apple/System/Library/CoreServices/XProtect.bundle; command line tool: xprotect
1
Term
Description
2
1TR
One True Recovery; booting into macOS recovery on Apple Silicon by holding the power button to verify physical presence; enables interaction with SEP to change Boot Policy
3
AA
Apple accountApple Account
4
AA
Apple Archive, see also Apple Encrypted Archive; command line tools: aa, aea, compression_tool
5
AAC
Automatic Assessment Configuration; AutomaticAssessmentConfiguration.framework; puts device in a locked mode for exam-style test applications
6
AAT
Apple Advanced Typography; font format and rendering engine
Apple Connect Device External? ACDEClient.framework, old two-step verification, derived from a company-internal AppleConnect system?
10
ACFS
Apple Clustered File System; deprecated file system for Xsan; acfs.framework
11
Acoustic ID
Siri feature to recognize songssong recognition and matching with Apple catalog, playback on HomePod; /System/Library/Components/AudioDSP.component
12
Activation
cryptographic check-in with iCloud to lock devices reported by the user as lost; verified by iBoot; MobileActivationMacOS.framework; launchd service: com.apple.mobileactivationd; servers: humb.apple.com, albert.apple.com
13
Activity
jobs, coarse-grained work units of applications; tracked by the system across XPC, bears a QoS class for scheduling; low-level mechanism not to be confused with User Activity
14
AE
Apple Events; messaging system to invoke application functionality; CoreServices.framework/AE.framework; launchd services: com.apple.coreservices.appleevents, com.apple.AEServer (AE over network)
15
Aegir
astronomy watch face and lock screen; /System/Library/CoreServices/AegirProxyApp.app
16
AFM
Apple Foundation Model; pre-trained transformer and diffusion models for Greymatter, optimized for on-device use by quantization (with accuracy-recovery adapters) and palletization; command line tool: modelcatalogdump
17
AGC
Apple Graphics Control, management of multiple displays and display port connections; launchd service: com.apple.displaypolicyd
18
AHAP
Apple Haptic Audio Pattern; file format for simultaneous audio and haptic data; CoreHaptics.framework
19
AIR
Apple Intermediate Representation; synthetic bytecode architecture target for GPU binary toolchain
20
ALF
Application-Layer Firewall, launchd service: com.apple.alf (socketfilterfw)Application-Layer Firewall; implemented as a Network Extension (see System Extension); launchd service: com.apple.alf (socketfilterfw); command line tool: socketfilterfw
21
Alloy
substrate for communication between user devices over Bluetooth and devices to iCloud, implemented over IDS; /System/Library/IdentityServices/ServiceDefinitions; launchd service: com.apple.identityservicesd
22
ALS
Ambient Light Sensor, AmbientDisplay.framework
23
Amber
Swift UI; SwiftUI.framework
24
AMFI
Apple Mobile File Integrity, checks code integrity based on code signature, stronger enforcement with hardened runtime, validates entitlement restrictions; launchd service: com.apple.MobileFileIntegrity (amfid, invoked by kernel through host special port 18); disabled by setting amfi_get_out_of_my_way=0x1 in boot-argsApple Mobile File Integrity, checks code integrity based on code signature, stronger enforcement with hardened runtime, validates entitlement restrictions and environment constraints (launch constraints, library constraints); launchd service: com.apple.MobileFileIntegrity (amfid, invoked by kernel through host special port 18); disabled by setting amfi_get_out_of_my_way=0x1 in boot-args
25
AMP
Apple Media Protocol? former parts of iTunes for iPod and iOS device access in Finder, Home Sharing; AMPDevices.framework, AMPSharing.framework; launchd services: com.apple.AMPDeviceDiscoveryAgent, com.apple.AMPDevicesAgent, com.apple.amp.mediasharingd
26
AMP
Asynchronous Multiprocessing; performance and power-efficiency cores on Apple Silicon
27
AMS
Apple Media Services; formerly the iTunes stores and media services: App Stores, Apple Music, Apple TV, iCloud media library, Apple Podcasts, Podcast sync, Books Store, Books sync; AppleMediaServices.framework; server: phobos.apple.com
32
AOS
Apple Online Services? historical name for iCloud
33
Apache
built-in web server; command line tool: apachectl
34
APFS
Apple File System; copy-on-write file system with support for volume space-sharing, per-file encryption, and snapshots
35
APNS
Apple Push Notification service, server infrastructure for remote push notifications over a single connection, clients subscribe to push topics, can be authenticated by app (remote notifications), device (Find My …), or Apple ID login (DSID); credentials in apsd keychain; launchd service: com.apple.apsd; server: push.apple.comApple Push Notification service, server infrastructure for remote push notifications over a single connection, clients subscribe to push topics, can be authenticated by app (remote notifications), device (Find My …), or Apple Account login (DSID); credentials in apsd keychain; launchd service: com.apple.apsd; server: push.apple.com
36
App Nap
quiescence detection for applications and corresponding self-demotion in scheduler parameters, implemented within application frameworks and RunningBoard, listens for occlusion notifications from WindowServer
37
App Sandbox
Seatbelt-based sandbox for apps; /System/Library/Sandbox/Profiles/application.sb; enabled with com.apple.security.app-sandbox entitlement; launchd service: com.apple.secinitd
Adaptive Picture Timing? ProMotion; dynamic screen updates with 120Hz base frequency; AppleDisplayTCONControl.framework
40
Ask To
parental-controlled user can ask parent for exceptions; launchd service: com.apple.asktod; AskTo.framework
41
ASL
Apple System Logger, superseded by Unified Logging; /etc/asl; stored in /var/log/asl; launchd service: com.apple.syslogd; command line tool: syslog
42
ASR
Apple Software Restore; restore entire volumes from sources like disk images (HDI, SIU), also restores based on APFS snapshots and snapshot deltas; command line tool: asr
43
Assertions
power state management allowing applications to prevent sleeping; launchd service: com.apple.powerd; command line tools: caffeinate, pmset
44
Assessment
checking of System Policy; term also used for AAC
45
Asset Cache
discretionary caching server for Mobile Assets, Packages, iOS updates, App Store content, ODR, MMCS data; launchd services: com.apple.AssetCache.builtin, com.apple.AssetCacheLocatorService, com.apple.AssetCacheManagerService, com.apple.AssetCacheTetheratorService; command line tools: AssetCacheLocatorUtil, AssetCacheManagerUtil, AssetCacheTetheratorUtil
46
Assistant
Siri; dictation and semantic understanding, Intent is communicated to and enacted on the client, uses TTS for output, Snippets to embed mini UIs into responses; /System/Library/Assistant, /System/Library/Snippets, AssistantServices.framework; server: *.siri.apple.comSiri; speech recognition and semantic understanding, dialog management by CDM, Intent is communicated to and enacted on the client, uses TTS for speech output, Snippets to embed mini UIs into responses; /System/Library/Assistant, /System/Library/Snippets, AssistantServices.framework; server: *.siri.apple.com
47
ATS
App Transport Security, sandbox mechanism only allowing TLS-secured connections
48
ATSUI
Apple Type Services for Unicode Imaging; rendering engine superseded by CoreText.framework, font management; ApplicationServices.framework/ATS.framework; launchd service: com.apple.xtyped (fontd); command line tools: atsutil
49
ATT
App Tracking Transparency; apps declare user tracking on app store
50
Attestation
cryptographic proof of a genuine SEP; used for web authentication and app attestation; DeviceCheck.framework; SEP responds to challenge using hardware-key (GID, PKA), online service verifies; used to pair Touch ID keyboards, used to pair RemoteXPC channel?
51
Authorization
discretionary access control policies for high-level services; similar to PAM; policy stored in /var/db/auth.db
52
Avatar
Memoji and Animoji, including pre-rendered iMessage stickers; AvatarKit.framework
53
AVB
Audio Video Bridging, low-latency audio over Ethernet; launchd service: com.apple.avbdeviced; command line tool: avbdiagnose, avbutilAudio Video Bridging, low-latency audio over Ethernet; launchd service: com.apple.avbdeviced; command line tools: avbanalyse, avbdiagnose, avbutil
54
AWD
Apple Wireless Diagnostics, sends system telemetry to Apple; CoreAnalytics.framework, WirelessDiagnostics.framework; launchd services: com.apple.awdd, com.apple.analyticsdApple Wireless Diagnostics, sends system telemetry to Apple; CoreAnalytics.framework, WirelessDiagnostics.framework; launchd services: com.apple.analyticsd
55
AWDL
Apple Wireless Direct Link; secondary WiFi interface that runs in parallel to an active WiFi access point connection, similar to WiFi Direct (p2p interface), uses a randomized MAC, used for peer-to-peer networking: AirDrop, AirPlay; DeviceToDeviceManager.framework
56
Background Assets
assets that an app extension loads without the app being launched; BackgroundAssets.framework; extension point: com.apple.background-asset-downloader-extension; launchd service: com.apple.backgroundassets.userassets that an app extension loads without the app being launched; BackgroundAssets.framework; launchd service: com.apple.backgroundassets.user
57
Bezel
on-screen overlays for hardware volume buttons, screen brightness, Bluetooth HID, and others; /Library/Application Support/Apple/BezelServices, launchd services: com.apple.loginwindow, com.apple.OSDUIHelper
CloudKit-based datastream and sync engine; BiomeStreams.framework, BiomeSync.framework; launchd services: com.apple.BiomeAgent, com.apple.biomesyncdCloudKit-synced streaming and storage of events like donated and invoked Intents; semantic index to ground AI with personal context; BiomeStreams.framework, BiomeSync.framework; launchd services: com.apple.BiomeAgent, com.apple.biomesyncd; embedding vector extraction and storage: ZeoliteFramework.framework
60
Blast Door
sandboxed sanitization process for untrusted iMessage input; BlastDoor.frameworksandboxed sanitization process for untrusted input, used for iMessage, IDS, Telephony, media analysis; BlastDoor.framework, CTBlastDoorSupport.framework, IDSBlastDoorSupport.framework, MediaAnalysisBlastDoorSupport.framework, MessagesBlastDoorSupport.framework, TelephonyBlastDoorSupport.framework
61
BOM
Bill of Materials; format to store contents of installer Packages; command line tool: lsbom
62
Bonjour
mDNS; launchd service: com.apple.mDNSResponder.reloaded; command line tool: dns-sd
63
Boot Cache
disk cache pre-heating at boot time with typically loaded applications; /var/db/BootCaches; launchd service: com.apple.warmd
69
Cache Delete
cleanup for various caches; /System/Library/CacheDelete; launchd service: com.apple.cache_delete (deleted)
70
CAML
Core Animation Markup Language; XML file format for layers, shapes and animations
71
Carousel
derivative of SpringBoard for Watch home screen, watch face, and notification center
72
CelestialCBOR
media streaming used by ReplayKit for game broadcasts; Celestial.frameworkConcise Binary Object Representation; JSON-inspired compact binary data serialization; CBORLibrary.framework
73
CDHash
Code Directory Hash; a hash of hashes over the parts of a code bundle; command line tool: codesign
74
CDM
Continuous Dialog Manager; natural dialog with Siri, MARRS for multi-modality; ContinuousDialogManagerService.framework
75
CEC
Consumer Electronics Control; remote control for HDMI-connected devices; CoreRC.framework, IOCEC.framework
76
Celestial
media streaming used by ReplayKit for in-app screen broadcasts; Celestial.framework; launchd service: com.apple.replayd
77
Certificates
validity checked using CRLs, OCSP stapling, and transparency logs; /System/Library/Security/Certificates.bundle; launchd services: com.apple.trustd, com.apple.trustd.agent, com.apple.ocspd; command line tool: crlrefresh
78
Chamois
Stage Manager
79
CHIP
Connected Home over IP; Matter; integrated into HomeKit; CHIPPlugin.frameworkConnected Home over IP; Matter; integrated into HomeKit, can use Thread as transport layer; HomeKitMatter.framework, CoreThread.framework; launchd services: com.apple.threadradiod, com.apple.ThreadCommissionerService
80
Circle
cryptographic primitive to exchange public keys of trusted devices of a user, signed by Circle peers; iCloud identity added as additional Circle peer, private key synced across all trusted devices, new devices can pull this key from Secure Backup to join the Circle; per-device Circles stored in CKKS for two-factor accounts (Octagon); KeychainCircle.framework; command line tools: otctl (Octagon)
81
CKKS
CloudKit Key Sync, end-to-end secure syncing for credentials, seeded by Circle; currently includes ApplePay, AutoUnlock, CreditCards, DevicePairing, Engram, Health, Home, Manatee, SOS, WiFi and other keys; launchd service: com.apple.secd; command line tool: ckksctl
82
CL4
Apple’s variant of the L4 microkernel, derived from Pistachio/seL4 and Wombat/Darbat
83
Clarity
customizable accessibility mode for simplified UI; ClarityFoundation.framework
84
Classroom
school teachers can create assignments for student iPads and track progress in Schoolwork app; ClassKit.framework; launchd service: com.apple.studentd
85
Cloud Pairing
part of Alloy, Bluetooth out-of-band pairing over iCloud for Continuity; launchd service: com.apple.BTServer.cloudpairing (cloudpaird)
86
CMAS
Commerial Mobile Alert System, now known as Wireless Emergency Alerts (WEA)
87
Commpage
user-mapped kernel data, like vdso/vsyscall on Linux; mapped at 0x7fffffe00000
88
Communications Filter
recipient blocking for iMessage, FaceTime, Mail; launchd service: com.apple.cmfsyncagent
89
Companion
iPhone that is paired with Watch; communication uses Alloy over IPsec over BluetoothiPhone that is linked with Watch, Mac, or Apple TV; communication with Watch uses Alloy over IPsec over Bluetooth, AWDL on demand; launchd service: com.apple.companiond; Bonjour service: _companion-link._tcp
90
ContinuityContact Key Verification
umbrella term for Handoff, Sidecar, SMS relay, Universal Clipboard, Watch unlock, WiFi call relay and others; SMS relay works by proxying to iMessage, other services use Alloycode for manual verification of iMessage keys; code identifies a long-lived account key stored in iCloud Keychain, which signs all ESS device keys
91
Continuity
umbrella term for Handoff, Sidecar, iPhone Mirroring, SMS relay, Universal Clipboard, Watch unlock, WiFi call relay and others; SMS relay works by proxying to iMessage, other services use Alloy for signalling and AWDL for payload; /System/Applications/iPhone Mirroring.app, ScreenContinuityServices.framework
92
Control Center
icons in menu/status bar and Bento Box controls UI, gradually replaces SystemUIServer on macOS; handles incoming AirPlay content; launchd services: com.apple.controlcenter, com.apple.SystemUIServer.agent
Cryptographically sealed Extension of SSV, mount-invisible extension of the root volume, allows lightweight updates as part of Rapid Security Response; /System/Cryptexes (mountpoint), /System/Volumes/Preboot/*/cryptex1/current/*.dmg (disk images)Cryptographically sealed Extension of SSV, mount-invisible overlay of the root volume, allows lightweight updates as part of Rapid Security Response; /System/Cryptexes (mountpoint), /System/Volumes/Preboot/*/cryptex1/current/*.dmg (disk images)
96
CSR
Configurable Security Restrictions; XNU subsystem that is the basis for SIP
97
CTK
Crypto Token Kit; smart card management, also for the Secure Element on iOS? launchd service: com.apple.ctkd; command line tool: sc_auth
98
CTS
Centralized Task Scheduling; execution of DAS tasks; /System/Library/UserEventPlugins/com.apple.cts.plugin
100
DAAP
Digital Audio Access Protocol; used by Home Sharing (with Rapport token) and by the Remote app to control Apple TV (with pairing token); payload unencrypted; DAAPKit.framework; Bonjour services: _atc._tcp, _home-sharing._tcp, _mediaremotetv._tcp, _touch-able._tcp
101
Daily Briefing
Siri giving an overview of information for the day; SiriDailyBriefingInternal.framework
102
DART
DMA Address Relocation Table; IOMMU implementation in Apple silicon, positioned in front of every DMA-capable co-processor and peripheral, offers sub-page protection; SART: streaming variant for high-throughput devices (like NVMe)
103
Darwin Directory
static store for users and groups, saves Open Directory interaction for the local case? /usr/lib/system/libsystem_darwindirectory.dylib, /System/Library/DarwinDirectory, /private/var/db/DarwinDirectory; command line tool: dddiagnose
text analysis to highlight phone numbers, street addresses, and the like; DataDetectors.framework
106
Data Vault
directories with the UF_DATAVAULT special flag; CSR limits access to one application
113
DFU
Device Firmware Update; special boot mode where iOS has not booted and the system can be installed over the Lightning connection
114
Differential Privacy
crowdsourcing without user tracking; privacy budget for management of anonymity set; used for keyboard words, emoji, Spotlight searches, Parsec deep links, HealthKit usage, Safari telemetry; /System/Library/DifferentialPrivacy; stored in /var/db/DifferentialPrivacy; launchd service: com.apple.dprivacyd
115
Digital Separation
safety check feature to inhibit sharing relationships; DigitalSeparation.framework
116
DMC
Device Management Client; part of MDM; DMCApps.framework, DMCUtilities.framework
117
DMC
Disk Mount Conditioner; simulates slow IO devices; command line tool: dmc
118
DND
Do Not Disturb
119
Dose
ambient sound level checking on Watch; /Applications/Dose.app
120
DSID
Destination Signaling Identifier, unique ID for IDS login on a specific device
telemetry collection engine for system and user events, forecasting by machine learning, backend for DAS, Proactive, Relevance, Screen Time, thermal and battery management; /System/Library/DuetKnowledgeBase; CoreDuet.framework, CoreKnowledge.framework, CorePrediction.framework; launchd services: com.apple.coreduetd, com.apple.knowledge-agent, com.apple.ospredictiondtelemetry collection engine for system and user events, forecasting by machine learning, backend for DAS, Proactive, Relevance, Screen Time, thermal and battery management; /System/Library/DuetKnowledgeBase, /System/Library/DuetExpertCenter; CoreDuet.framework, CoreKnowledge.framework, CorePrediction.framework, CascadeEngine.framework (link to Biome); launchd services: com.apple.coreduetd, com.apple.duetexpertd, com.apple.knowledge-agent, com.apple.ospredictiond
123
Dyld Shared Cache
dynamic linker cache, stores all system libraries in prelinked form, original library files are removed; /System/Volumes/Preboot/Cryptexes/OS/System/Library/dyld; command line tools: dyld_info, dyld_usage, update_dyld_shared_cache
124
EAS
Exchange Active Sync; network protocol for accessing Microsoft Exchange servers
125
Ecosystem
tracks usage of system functionalty by apps, can inform user to trigger responses; Ecosystem.framework; launchd services: com.apple.ecosystemd, com.apple.ecosystemagent
126
EDR
Extended Dynamic Range; rendering with transfer function extending beyond sRGB white; implemented natively on XDR displays and by backlight modulation on others; HDRProcessing.framework
127
Energy Impact
unitless metric for per-application energy consumption, machine-specific coefficients; /usr/share/pmenergy, /usr/share/kpep; launchd services: com.apple.sysmond, com.apple.thermald; command line tool: powermetricsunitless metric for per-application energy consumption, machine-specific coefficients; /usr/share/pmenergy, launchd services: com.apple.sysmond, com.apple.thermald; command line tool: powermetrics
128
Engram
Messages in iCloud; devices store received iMessages in CloudKit; Engram.framework
129
Entitlements
capability-like attributes bound to executables by code signing; some entitlements like App Sandbox restrict ambient authority, some gradually relieve those restrictions (using Seatbelt), some services or system calls grant privilege based on caller entitlements
130
ESS
IDS user directory, public key distribution for iMessage and CloudKit sharing, uses Transparency; server: *.ess.apple.com; launchd service: com.apple.identityservicesd
131
Exclave
user-level portions of kernel or SEP services, used for paravirtualized access by VMs; /usr/libexec/init_exclavekit
132
Eye Relief
screen distance warning for handheld devices; /Applications/EyeReliefUI.app
133
FaceTime
video calls, employs the ICE (establishing peer-to-peer connection), STUN (session credential exchange) and SRTP (encrypted media streaming) protocols; FTServices.framework; launchd services: com.apple.videoconference.camera (avconferenced)
134
FairPlay
DRM system used by app and media stores; CoreADI.framework, CoreFP.framework, CoreLSKD.framework; launchd services: com.apple.adid, com.apple.fairplayd (invoked by kernel through host special port 17), com.apple.lskdd; credentials stored in /var/db/fpsd
135
Family Circle
Family Sharing; launchd services: com.apple.familycircled, com.apple.askpermissiond
136
FDE
Full Disk Encryption, FileVault; command line tool: fdesetup, sysadminctl
137
FDR
Factory Data/Device Reset? ensures that no downgrades are performed? servers: skl.apple.com, gg.apple.com; /System/Library/FDR
138
Feldspar
Apple News; Silex.framework
139
FiDES
Fi? Distributed Evaluation Service? aggregates Differential Privacy data for unlinkability? maybe private federated learning? used for emoji, Suggestions, Dictation; /System/Library/DistributedEvaluation; DistributedEvaluation.framework; server: fides-pol.apple.comFi? Distributed Evaluation Service? aggregates Differential Privacy data for unlinkability? used for emoji, Suggestions, Dictation; /System/Library/DistributedEvaluation; DistributedEvaluation.framework, FedStats.framework (private federated learning?)
140
File Provider
infrastructure and extension system for syncing with cloud providers; placeholder files based on SF_DATALESS attribute in APFS; FileProvider.framework; locally stored in ~/Library/CloudStorage; command line tool: fileproviderctl
141
Find My …Find My
location sharing by explicitly querying devices remotely or collateral beacon detection using Search Party; FMCore.framework, FMF.framework; launchd service: com.apple.icloud.fmfd (find my friends)location sharing by explicitly querying devices remotely or collateral beacon detection using Search Party; FMCore.framework, FMF.framework
142
Firmlink
bi-directional non-symbolic link between the read-only system volume and the data volume, additional symlinks and mountpoints in the root directory are virtually allocated; /usr/share/firmlinks, /etc/synthetic.conf
143
Focus
restriction modes for notification presentation; focus filters for in-app display restrictions, communicat by Intents; Focus.framework, DoNotDisturb.framework; local settings in ~/Library/DoNotDisturbrestriction modes for notification presentation; focus filters for in-app display restrictions, communicated by Intents; Focus.framework, DoNotDisturb.framework; local settings in ~/Library/DoNotDisturb
144
FollowUp
user interaction for Secure Backup wrapping with device passcode, CoreFollowUp.framework; launchd service: com.apple.followupd
145
FoundationDB
fundamental iCloud storage database, marketed as CloudKit, separated into containers; records, blobs, and large asset storage with MMCS, server-side continuous queries can trigger push notifications, user management by IDS, sharing between users; PCS keys used for hierarchical zone, record, and asset encryption; CloudKitDaemon.framework; launchd service: com.apple.cloudd; locally stored in ~/Library/Caches/CloudKit, ~/Library/Containers/*/Data/CloudKit; command line tool: cktoolfundamental iCloud storage database, marketed as CloudKit, separated into containers; records, blobs, and large asset storage with MMCS, server-side continuous queries can trigger push notifications, user management by IDS, sharing between users by GroupKit; PCS keys used for hierarchical zone, record, and asset encryption; CloudKitDaemon.framework; launchd service: com.apple.cloudd; locally stored in ~/Library/Caches/CloudKit, ~/Library/Containers/*/Data/CloudKit; command line tool: cktool
146
FPR
Fast Permission Restrictions; Apple CPU registers to downgrade (old APRRs do bitmasking) or remap (SPRRs since M1) actual permissions of memory pages (the CTRR region) per thread; used for JIT protection and by AMFI to freeze user code after checkingFast Permission Restrictions; Apple CPU registers to downgrade (old APRRs do bitmasking) or remap (SPRRs since M1) actual permissions of memory pages (the CTRR region) per thread
user space file system support; kernel stub file system is /System/Library/Extensions/lifs.kext; file systems are in /System/Library/ExtensionKit/Extensions/com.apple.fskit.*; launchd service: com.apple.filesystems.fskitd, com.apple.filesystems.doubleagentd (handling of Apple double files in user space); extension point: com.apple.fskit.fsmodule
149
FUD
Firmware Update Daemon; see TSS, UARP; launchd service: com.apple.accessoryupdaterd
150
Game Mode
auto-activates when games are shown full screen, throttles background work, lowers audio and input latency; launchd service: com.apple.gamepolicyd
151
GID
group ID key, shared across all devices of the same SoC generation, derived keys are used to prove device type over the network, only accessible by SEP
152
Gizmo
Apple Watch; watch settings managed by Companion; /Applications/Bridge.app, /System/Library/BridgeManifestsApple Watch; watch settings managed by Companion iPhone; /Applications/Bridge.app, /System/Library/BridgeManifests
153
Greymatter
Apple Intelligence; on-device language and diffusion models, larger server-based models in PCC; AFM refined for specific tasks (queries, summarization, categorization) by adapters (parameter for inserted network modules); grounded with context from Biome and intelligence stores; ~/Library/IntelligencePlatform; launchd service: com.apple.modelmanagerd (model residency management); /System/Library/ModelManager/Policy.plist; /Applications/Tamale.app (Camera Control integration); command line tool: csfdiagnose (cloud subscription features), modelmanagerdump
154
Group Activities
SharePlay; sharing of media content and programmatic state over FaceTime calls; GroupActivities.framework, CopresenceCore.framework; launchd service: com.apple.telephonyutilities.callservicesd
155
GroupKit
groups of IDS users with shared CloudKit (PCS) access; GroupKitCrypto.framework
156
GSS
Generic Security Service; part of Kerberos; GSS.framework; launchd service: com.apple.gssd (invoked by kernel through host special port 19); command line tool: gsstool
157
GXF
Guarded Execution Feature/Fault, additional exception levels on Apple Silicon, lateral to the usual exception levels; page tables remain the same, but interpretation of permission bits changes by way of FPR, genter and gexit instructions; implements lightweight intra-address-space protection contexts
158
HAP
Home Automation Protocol; CoreHAP.framework
HDA
High Definition Audio; HDAInterface.framework
159
HDI
Hard Disk Image; command line tool: hdiutil
160
HeadBoard
derivative of SpringBoard for tvOS home screen; /Applications/HeadBoard.app, /Applications/PineBoard.app
161
Health Balance
vitals app on Watch; /Applications/NanoHealthBalance.app
162
HLS
HTTP Live Streaming
163
HomeEnergy
HomeKit management for grid energy supply; EnergyKit.framework
164
HSA
Hardware Security Architecture; version 1 used for two-step verification, SOS with iCSC; version 2 for two-factor authentication, CKKS and Secure Backup with iCDP
165
HSM
Hardware Security Module; HSM fleet runs escrow service for Secure Backup
boot loader stage after boot ROM or UEFI (macOS on Intel); intermediate Low-Level Bootloader (LLB); DFU mode is implemented here; /System/Library/CoreServices/boot.efi
169
iCDP
iCloud Data Protection, codename for a set of enhancements to iCloud privacy: device passcodes used as iCSC for Secure Backup, root keys for CKKS-enabled services only synced between devices and not stored at Apple; launchd service: com.apple.cdpd
170
iCloud
umbrella term for a conglomerate of services, consists of FoundationDB containers with PCS views for key management, supported by CKKS; uses IDS and APNS; some services under the iCloud name are actually served by AMS, IMAP, or DAV
171
iCSC
iCloud Security Code, credential wrapping for Secure Backup, previously used a separate code, with HSA2/iCDP uses device passcodes
172
IDAM
Inter-Device Audio and MIDI; audio connection between devices
173
IDS
Identity Service, also IDMS, Apple ID identity management for all of Apple’s online services; APNS topics for signaling and messaging, see also Alloy, ESS, FaceTime, iMessage; authentication to services with KerberosIdentity Directory Service, also IDMS, Apple Account identity management for all of Apple’s online services; APNS topics for signaling and messaging, see also Alloy, ESS, FaceTime, iMessage; authentication to services with Kerberos
174
IDV
Identity Verification? Touch ID and Face ID; /System/Library/AccessibilityBundles/CoreIDVUI.axbundle
175
IM
Instant Messaging; usually means iMessage and FaceTime
176
IMG4
boot files (Mach-O binaries or configuration data) with ASN.1 signature, contains RemotePolicy certificate constraints to restrict Boot Policy evaluation
177
Intent
use-case-driven interaction with 3rd-party apps from a host app; used for Siri, Maps, Shortcuts, Widgets (configuration); definition file or programmatically using AppIntents.framework; command line tool: appintentsmetadataprocessor (Xcode extracts Intent definition at compile time); extension points: com.apple.intents-service, com.apple.intents-ui-servicesemantic interaction between app and system (or another app); used for Siri, Shortcuts, Maps (contextual suggestion), Widgets (configuration); definition by file or programmatically using AppIntents.framework; command line tool: appintentsmetadataprocessor (Xcode extracts Intent definition at compile time); extension points: com.apple.intents-service, com.apple.intents-ui-service
178
IOKit
device driver subsystem for in-kernel and DriverKit drivers, command line tool: ioreg
179
Ironwood
dictation, customized on server with selected user data (contacts, app names, music titles, HomeKit names, Siri Shortcut phrases), not tied to Apple ID; SpeechRecognitionCore.framework; server: guzzoni.apple.comdictation, customized on server with selected user data (contacts, app names, music titles, HomeKit names, Siri Shortcut phrases), not tied to Apple Account; SpeechRecognitionCore.framework, ASRBridge.framework; server: guzzoni.apple.com
180
ISP
Image Signal Processor; camera imaging circuit in iPhones
181
ITML
iTunes Markup Language; metdata tagging for media services; ITMLKit.framework
182
ITP
Intelligent Tracking Prevention, cross-site tracking defenses in Safari, statistics and user interaction classify sites, cookies are partitioned and access is restricted
183
JARVIS
Just A Rather Very Intelligent Scheduler, Mesos cluster manager for Siri, iCloud, AMS
184
Jellyfish
Animoji; /Applications/Jellyfish.app
185
Jetsam
reclaiming of purgeable memory and termination of apps during memory pressure
186
Journal
diary app; JournalShared.framework
187
JSC
JavaScript Core; JavaScriptCore.framework; command line tool: jsc
188
Kalamata
codename for the transition from x86 to ARM-based Apple Silicon
189
Kerberos
single-sign-on mechanism; Heimdal.framework; command line tools: kinit, ktutil
190
Kext
kernel extension mechanism, loaded at boot time as part of a Kext Collection; /Library/Extensions, /Library/StagedExtensions (for user approval), /System/Library/Extensions; command line tool: kextutil (manages deprecated runtime loading)
191
Kext Collection
prelinked sets of kernel extensions; /System/Library/KernelCollections (for boot and system kexts), /Library/KernelCollections (for auxiliary third-party kexts); the latter is only loaded at a lower-security Boot Policy; launchd service: com.apple.kernelmanagerd (invoked by kernel through host special port 15); command line tool: kmutil
192
Keybag
storage of protection class keys for Keychain and filesystem, protected by SEP using SKP; stored in user.kb; launchd services: com.apple.mobile.keybagd, com.apple.securityd_service, com.apple.secdstorage of protection class keys for Keychain and filesystem, protected by SEP using SKP; stored in user.kb; launchd services: com.apple.mobile.keybagd, com.apple.secd
193
Keychain
storage for credentials; launchd service: com.apple.securityd; command line tools: certtool, security, systemkeychain
194
KIP
Kernel Integrity Protection, locking of physical memory pages to prevent changes to kernel
195
Launch Services
management for application launches, association of UTIs to apps, uses Spotlight to update cached info; launchd services: com.apple.coreservices.launchservicesd, com.apple.lsd; CoreServices.framework/LaunchServices.framework; command line tools: lsappinfo, lsregister
196
Liquid Glass
UI design language, includes icon treatment; IconRendering.framework, LightSourceSupport.framework
197
Live Files
user mode filesystems, currently FAT, ExFAT, NTFS on external storage; UserFS.framework, UVFSXPCService.framework; launchd service: com.apple.filesystems.userfsd
198
Liverpool
PCS codename for CloudKit
199
LKDC
Local Key Distribution Center, Kerberos on client machines
201
Mac Buddy
historic name for Setup Assistant
202
MAC Policy
Mandatory Access Control subsystem in XNU, based on TrustedBSD, implements policy hooks for restricted kernel operations; current policies: AMFI, Seatbelt, Quarantine, CSR
203
Machine Learning
Vision.framework, Espresso.framework, Futhark.framework, PhotoAnalysis.framework; used for Live Text and Visual Lookup; launchd service: com.apple.mediaanalysisd
PCS key for some CloudKit containers are synced via CKKS, so data is unreadable to Apple (credential management codenames: Plesio, Stingray, Cuttlefish)
206
Mandrake
emergency siren on Apple Watch Ultra; /Applications/Mandrake.app
207
Mangrove
transfering UI tiles over XPC; Mangrove.framework, IOSurface.framework
208
Marco
Marco.framework, something about IDS and communication (iMessage, Calls), logging?
209
Marklar
codename from the PowerPC era for the port to x86, served the transition to Intel CPUs
210
MARRS
Multimodal Reference Resolution; Marrs.framework
211
Marzipan
Catalyst; port of iOS frameworks to macOS, Catalyst apps are iOS apps with additional API to adapt macOS UI idioms; /System/iOSSupport; integration using UIKit system process; launchd service: com.apple.uikitsystemapp; input remapping by /Library/Apple/Library/Bundles/InputAlternatives.bundle
212
MCX
Managed Client for OS X, preference management for settings from configuration profiles, /Library/Managed Preferences, command line tools: mcxquery, mcxrefresh
213
MDM
Mobile Device Management; server software to manage fleets of iOS and macOS devices; uses configuration profiles to manage preferences; ConfigurationProfiles.framework
214
MDS
Module Directory Services, ancient part of the old security APIs (CSDA, CSSM)
215
Memory Debugging
uses Taskport; command line tools: heap, leaks, malloc_history, stringdups, vmmap
MobileMe Chunk Storage, used by iCloud, splits blobs into chunks and stores them at Apple/AWS/GCP with convergent encryption (content hash as key); MMCS.framework
221
Mobile
prefix for iOS
222
Mobile Assets
demand-downloaded system components like fonts, dictionaries, linguistic data; stored in /System/Library/Assets; launchd services: com.apple.languageassetd (language-dependent assets), com.apple.mobileassetd; server: mesu.apple.com
223
Mobile Device
connectivity to iOS devices over USB or WiFi (AirTrafficHost) for syning, development, and debugging; MobileDevice.framework; launchd service: com.apple.usbmuxd; Bonjour service: _apple-mobdev2._tcp
224
MOC
Managed Object Context; Core Data object space
225
Mondrian
photo collage arrangement in Photos.app; Mondrian.frameworkphoto collage arrangement in Photos.app; Mondrian.framework, GridZero.framework
226
MRT
Malware Removal Tool; /Library/Apple/System/Library/CoreServices/MRT.appMalware Removal Tool; /Library/Apple/System/Library/CoreServices/MRT.app; superseded by XProtect
227
Multipeer Connectivity
ad-hoc networking; Bonjour for discovery; WiFi, AWDL, Bluetooth, or Ethernet as transport; optional encryption and certificate-based authentication; MultipeerConnectivity.framework
228
Nano
prefix for watchOS
229
Nearby Interaction
proximity-based interaction between devices; proximity measured using ultra wideband or derived from other technologies; used for Universal Control; NearbyInteraction.framework, Proximity.framework; launchd service: com.apple.nearbydproximity-based interaction between devices; proximity measured using ultra wideband or derived from other technologies; used for Universal Control, tapping phones for AirDrop; NearbyInteraction.framework, Proximity.framework; launchd services: com.apple.aonsensed (always-on sense daemon), com.apple.nearbyd
230
Nebula
sleep apnea detection on watchOS; BreathingAlgorithms.framework
Natural Language Processing; NLP.framework; related to mecabra libraries, a linguistic engine for Chinese and Japanese; /usr/share/mecabra, /usr/share/tokenizer
234
NLU
Natural Language Understanding; Greymatter Siri engine; SiriNLUTypes.framework, SiriNaturalLanguageParsing.framework
235
Notarization
app security scan by Apple; cryptographic proof stapled to code signature, tested at launch by System Policy; for non-notarized apps sends code hash to Apple; command line tools: notarytool, altool, stapler
236
Noticeboard
User Notifications for Software Update and App Store, Noticeboard.framework; launchd services: com.apple.noticeboard.state (nbstated), com.apple.noticeboard.agent (nbagent)
237
Notifications
system notification bus, unrelated to the local/remote push notifications; launchd service: com.apple.notifyd, com.apple.kuncd (invoked by kernel through host special port 10); command line tool: notifyutil; complemented by framework-level notification system (CFNotification, NSNotification); launchd services: com.apple.distnoted.xpc.daemon, com.apple.distnoted.xpc.agent
238
NSP
Network Service Proxy; per-app VPN and proxy settings, implements Private Relay; launchd service: com.apple.networkserviceproxy
239
OAH
Rosetta; ahead-of-time compiler for Intel code on Apple Silicon, usable from Linux VMs by way of a custom binformat; /usr/libexec/rosettaRosetta; ahead-of-time compiler for Intel code on Apple Silicon, usable from Linux VMs by way of a custom binformat; /usr/libexec/rosetta, /var/db/oah (AOT cache); launchd service: com.apple.oahd
240
ODR
On-Demand Resources; loaded from App Store; launchd service: com.apple.appstored
241
Omni Search
fuzzy semantic search with results recognized in images; OmniSearch.framework
242
Onboarding
data protection splash screen shown by service-connected apps; /System/Library/OnBoardingBundles; OnBoardingKit.framework
243
Open Directory
directory service for user, group, and machine management; plugin-based to use different backend stores (LDAP, Active Directory), local accounts in /private/var/db/dslocal; launchd service: com.apple.opendirectoryd; command line tools: dscacheutil, dscl, dsconfigad, dsconfigldap, dseditgroup, dsenableroot, dserr, dsexport, dsimport, dsmemberutil, odutildirectory service for user, group, and machine management; plugin-based to use different backend stores (LDAP, Active Directory), local accounts in /private/var/db/dslocal, populated from /System/Library/DirectoryServices/DefaultLocalDB; launchd service: com.apple.opendirectoryd; command line tools: dscacheutil, dscl, dsconfigad, dsconfigldap, dseditgroup, dsenableroot, dserr, dsexport, dsimport, dsmemberutil, odutil
244
OpenBSM
Open Basic Security Module; deprecated security audit subsystem; /etc/security, /var/audit; launchd service: com.apple.auditd; command line tool: audit
245
Opus
create slide shows from photos; Slideshows.framework
246
OSA
Open Scripting Architecture; scripting of applications from different fontend languages (currently AppleScript and JavaScript); backed by Apple Events; command line tools: osacompile, osadecompile, osalang, osascript, sdef, sdp
248
PAC
Pointer Authentication Codes; pointers signed in unused bits to prevent ROP attacks
249
Packages
unit of software installation; command line tools: pkgutil, installer, softwareupdate; launchd services: com.apple.softwareupdated, com.apple.bootinstalld, com.apple.installd, com.apple.system_installd, com.apple.uninstalld; /var/db/softwareupdate, /Library/Apple/System/Library/Receipts (system), /System/Library/Receipts (read-only), /private/var/db/receipts (App Store)
250
Packet Filter
network traffic filtering subsystem from OpenBSD; command line tool: pfctl
251
Parsec
Spotlight web results and searching of crowdsourced User Activity deep links; server: *.smoot.apple.com; launchd services: com.apple.parsecd, com.apple.parsec-fbf (Feedback Flush to Differential Privacy)Spotlight web results and searching of crowdsourced Intent deep links; server: *.smoot.apple.com; launchd services: com.apple.parsecd, com.apple.parsec-fbf (Feedback Flush to Differential Privacy); telemetry collection with Poirot: PoirotSQLite.framework, PoirotUDFs.framework, SearchOnDeviceAnalytics.framework
252
Party Studio
Karaoke mode on tvOS, where video from a paired phone is shown with effects; PartyStudio.framework; /Applications/Sing.app
253
Passkey
keypair used for authentication instead of password, synced via SOS, implements WebAuthn standard; keys can be used to login on separate device via QR code and Bluetooth proximity proof; AuthenticationServices.framework
254
Password Breach
monitoring of Keychain passwords against a breach database; round-robin matching in fixed-size batches, local match against common leaks, remote match using hash prefix; launchd service: com.apple.Safari.passwordbreachd
255
Pasteboard
storage for cut, copy, and paste; type of content remembered as UTI; launchd service: com.apple.pboard; command line tools: pbcopy, pbpaste
256
PAT
Private Access Tokens; blind challenge-response authentication; Apple server attests user validity to token issuer, issuer performs blind signature, websites receiving the token cannot identify user; used for Private Relay, can replace CAPTCHAs
257
PCSPCC
Protected Cloud Storage; key management for separate iCloud storage compartments (PCS calls them views), each can contain FoundationDB plus bulk data stored by MMCS; see also iCDP, CKKS, Manatee; ProtectedCloudStorage.framework; /System/Library/Preferences/ProtectedCloudStorage; command line tool: pcsstatusPrivate Cloud Compute; server-based AFM for AI, running on Apple Silicon managed by SEP; stateless computation, PAT to authorize user, Attestation of remote code by device, measurements published in Transparency; ~/Library/PrivateCloudCompute; launchd services: com.apple.privatecloudcomputed, com.apple.swtransparencyd
258
PCS
Protected Cloud Storage; key management for separate iCloud storage compartments (PCS calls them views), each can contain FoundationDB plus bulk data stored by MMCS; see also iCDP, CKKS, GroupKit, Manatee; ProtectedCloudStorage.framework; /System/Library/Preferences/ProtectedCloudStorage; command line tool: pcsstatus
259
PCSC
Personal Computer Smart Card; PCSC.framework, uses CTK
260
PDE
Print Dialog Extension; old name, not a proper Extension
261
Peak Power
managing battery power draw; launchd service: com.apple.peakpowermanagerd; /System/Library/PPM/BatteryModels
262
PEC/PIR
Private Encrypted Compute and Private Information Retrieval; used for parental controls for media and web; CipherML.framework; launchd service: com.apple.ciphermld
263
Pegasus
meaning 1: picture-in-picture video playback; Pegasus.framework (iOS), PIP.framework (macOS); meaning 2: online search query engine for visual lookup; PegasusKit.framework
264
PepperPeople
UI elements for Watch home screen and Chat, like Quickboard (canned replies), Animoji; PepperUICore.frameworkcontacts with Apple Accounts within Group Activities and Shared With You
265
Persona
separation of sub-user-identities, like when using a private and managed Apple account; PersonaKit.framework; ~/Library/Personas; /System/Library/UserManagement; command line tool: umtool
266
PHASE
Physical Audio Spatialization Engine; 3D sound rendering engine; Apple devices map audio sources (even mono and stereo) to virtual speakers in a 3D sound stage, which is simulated by the physical speakers via a head-related transfer function; PHASE.framework
267
Piano Mover
Mail Drop; bulk mail attachments transfered over PCS; not to be confused with storage for iMessage attachments, which uses a CloudKit container
268
Plugin
Extensions, XPC services bundled with apps or frameworks, discovery by Launch Services; launchd service: com.apple.pluginkit.pkd; command line tool: pluginkitExtensions, XPC services bundled with apps or frameworks, discovery by Launch Services; extension points listed in /System/Library/ExtensionKit/ExtensionPoints; launchd service: com.apple.pluginkit.pkd; command line tool: pluginkit
battery management like smart charge and power save, learns from Duet and other data; PowerUI.framework; /var/db/PowerUI; launchd service: com.apple.PowerUIAgent
273
Preferences
storage for user-configurable settings; launchd services: com.apple.cfprefsd.xpc.daemon, com.apple.cfprefsd.xpc.agent; stored in Library/Preferences, command line tool: defaults; interaction with Synced Defaults per /System/Library/DefaultsConfigurations
274
Preview Shell
skeleton for on-device UI previews during development; /System/Library/CoreServices/PreviewShell.app; PreviewShellKit.framework, XOJIT.framework (code live patching)
275
Private Relay
two-hop onion routing with one entry and one exit node; Apple operates entry, third-party services operate exit nodes; QUIC for payload, ODoH for DNS, approximate IP geolocation via Waldo, authentication via PAT
276
Proactive
umbrella term for suggestions and completions based on Duet forecasting and User Activity context, also marketed as Siri features; PersonalizationPortrait.frameworkumbrella term for suggestions, completions, and summarizations based on Duet forecasting, Biome, and Intent context; PersonalizationPortrait.framework, ProactiveMagicalMoments.framework, ProactiveSummarization.framework
277
Provenance
per-file origin tracking, extended attribute com.apple.provenance stores ID into /var/db/SystemPolicyConfiguration/ExecPolicy
278
QoS Classes
inheritable property for Activities; semantic priorities, influences scheduling parameters; initially set at user-level, priority inheritance within GCD queues and across XPC in kernel?
279
Quagga
framework for QR and barcode decoding; Quagga.framework
280
Quick Action
extension type for quick interaction with foreign content within a host app; extension points: com.apple.services, com.apple.ui-services
281
Quick Look
file preview and thumbnail generation; comand line tool: qlmanage
device pairing by proximity using Alloy, with PIN entry, or using iCloud; once paired, devices can access services; used for HomeKit, HomePod, AirPlay, Home Sharing, SideCar; Rapport.framework; launchd service: com.apple.rapportd; Bonjour service: _companion-link._tcpdevice pairing by proximity using Alloy, with PIN entry, or using iCloud; once paired, devices can access services; used for HomeKit, HomePod, AirPlay, Home Sharing, SideCar; Rapport.framework, ProximityAppleIDSetup.framework; launchd service: com.apple.rapportd
284
RCS
Rich Communication Services; messaging service in mobile networks, successor to SMS; IMRCSTransfer.framework; /System/Library/Messages/PlugIns/RCS.imservice
285
Recents
recently used items (not files) in various applications, synced with Synced Defaults; CoreRecents.framework, /System/Library/Recents; launchd service: com.apple.recentsd
286
Relevance Engine
backend for Siri suggestions (for example of Siri Shortcuts), Widget smart stacks (also Siri watch face); consumes Duet knowledge and app-provided timelines with relevance hints; /System/Library/RelevanceEngine; launchd service: com.apple.relevancedbackend for Siri suggestions (for example of Siri Shortcuts), Widget smart stacks (also Siri watch face); consumes Duet knowledge and app-provided timelines with relevance hints; /System/Library/RelevanceEngine
287
Remote Pairing
Mobile Device pairing without wired connection; RemotePairingDevice.framework; Bonjour services: _remotepairing._tcp, _remotepairing-manual-pairing._tcp
288
RemoteXPC
connection to a non-SoC-integrated SEP like Bridge; uses HTTP/2 over a network interface, Bridge connected over USB, secured using Attestation; RemoteServiceDiscovery.framework, TrustedAccessory.framework; launchd service: com.apple.remoted, com.apple.tracd; command line tool: remotectl
289
Replicator
notification sync from Companion iPhone, also drives remotely displayed live activities; ReplicatorServices.framework; launchd service: com.apple.replicatord
290
Revisions
document autosave and auto-versioning; stored in .DocumentRevisions-V100; GenerationalStorage.framework; launchd service: com.apple.revisiond
291
Routine
frequently visited locations on iOS, interacts with Duet; launchd service: com.apple.routined
292
RTC
Real-time Telemetry and Crash reporting; RTCReporting.framework; launchd service: com.apple.rtcreportingd
293
RTKit
operating system used on Apple Silicon for firmware of co-processorsreal-time runtime used for firmware of Apple Silicon co-processors; on top of CL4 in Apple’s cellular modem
294
RunningBoard
runtime management of apps, paradigm: app as service process invoked by system, check-in by frameworks, handles process assertions (frontmost app, see App Nap), memory pressure (see Jetsam) and compute resources (GPU), replacement for TAL?; launchd service: com.apple.runningboardd; /System/Library/LifecyclePolicy, /System/Library/RunningBoard
295
Safety Monitor
Check In; short-term location sharing in iMessage until a destination is reached; /Applications/SafetyMonitorApp.app
296
Salt & Pepper
UI elements for Watch; SaltUICore.framework, PepperUICore.framework
297
SBPL
Sandbox Profile Language; a TinyScheme-based embedded DSL for Seatbelt profiles
298
SCIP
System Coprocessor Integrity Protection; like KIP, but for SEP, ISP, Motion coprocessor
299
Screen Reader
VoiceOver and Braille; /System/Library/ScreenReader; ScreenReader.framework
302
Search Party
portion of Find My service for offline devices; devices emit public part of rotating key pair via Bluetooth LE, other devices encrypt current location with this key and send to Apple, private key shared over CloudKit
303
Seatbelt
process sandbox by filtering system calls; profiles written in SBPL; /System/Library/Sandbox/Profiles, /usr/share/sandbox; default file access policy asks for TCC confirmation before access to folders with user data (like Documents) is allowed; command line tool: sandbox-exec; launchd service: com.apple.sandboxd (invoked by kernel through host special port 14 for logging)
304
Secure Backup
escrow part of CKKS; escrow key individually wrapped with passcodes of trusted devices, stored in HSM to prevent brute forcing, uses SRP so passcodes are not visible to iCloud, limited number of recovery attempts; protocol called Lakitu, uses FollowUp; launchd service: com.apple.SecureBackupDaemon (com.apple.sbd); CloudServices.framework
305
SEP
Secure Enclave Processor; dedicated ARM core for security services, runs L4/Darbat-based sepOS, inline encryption to DRAM, manages AES keys in storage DMA engine, factory-paired channels to Touch ID/Face ID hardware, Secure Element, Neural Engine; SEP can use but not read UID and GID keys; credential verification performed by hardware lockbox with retry count enforcementSecure Enclave Processor; dedicated ARM core for security services, runs CL4-based sepOS, inline encryption to DRAM, manages AES keys in storage DMA engine, factory-paired channels to Touch ID/Face ID hardware, Secure Element, Neural Engine; SEP can use but not read UID and GID keys; credential verification performed by hardware lockbox with retry count enforcement
306
Sequoia
translation; downloadable language models can run on-device; /Applications/SequoiaTranslator.app, Translation.framework
307
Seymour
Apple Fitness+; workout videos integrated with Watch sensors; SeymourCore.frameworkApple Fitness+; workout videos integrated with Watch sensors; SeymourCore.framework, Blackbeard.framework (personalisation and workout programs)
308
SF Symbols
scalable UI symbols; rendered with various color treatments; SFSymbols.framework
309
Shared File List
lists of recently opened files from apps that are stored with Launch Services; command line tool: sfltool; also manages login items and app-installed background daemons
310
Shared With You
collaboration features between apps and iMessage; content shared via iMessage is surfaced in apps (Swift Transferable protocol), content in apps can be collaboratively edited and connected to an iMessage group; collaborations are expressed by keys derived from participant device keys, padded with a number of random keys to prevent tracking of device count, a merkle tree of those keys is used to prove inclusion of a specific device to an app; SharedWithYou.framework
311
Sharing
umbrella term for wireless proximity services: AirDrop, Continuity, Instant Hotspot, WiFi sharing; used by loginwindow for Watch unlock; Sharing.framework; launchd service: com.apple.sharingd; also serves connection sharing and remote disk
using iPhone/iPad as Mac accessory: external camera and microphone (ContinuityCapture), camera for photos and scanning (DocumentCamera.framework), external display over low-latency WiFi (llw interface) using avconferenced encoding; SidecarCore.framework; launchd services: com.apple.sidecar-display-agent (SidecarDisplayAgent), com.apple.sidecar-relay (SidecarRelay)using iPhone/iPad as Mac accessory: external camera and microphone (ContinuityCapture), camera for photos and scanning (DocumentCamera.framework), iPad as display over low-latency WiFi (llw interface) using avconferenced encoding; /Applications/Sidecar.app; SidecarCore.framework; launchd services: com.apple.sidecar-display-agent (SidecarDisplayAgent), com.apple.sidecar-relay (SidecarRelay)
315
Signpost
telemetry API to report points of interest in code; launchd service: com.apple.signpost.signpost_reporter
316
SIL
Secure Indicator Light; microphone and camera indicator on iPads rendered in hardware
317
Simulator
running an iOS/tvOS/watchOS personality on macOS, uses sandboxing and a separate Mach bootstrap namespace for container-like isolation; installable simulators as disk images in /Library/Developer/CoreSimulator/Images; command line tool: simctl
318
SIP
System Integrity Protection or rootless mode; collection of kernel-level security restrictions regarding file system modification, unsigned Kexts, Taskport access, NVRAM access, DTrace; /System/Library/Sandbox/rootless.conf; command line tool: csrutil, rootless-init
319
Site Association
signed files in .well-known directory on websites; equivalent to Entitlements for websites, associates domains with app IDs for Universal Links; command line tool: swcutil
323
Skywalk
network subsystem in XNU, links together actual technologies (Bluetooth, WiFi, Thunderbolt) and interfaces/tunnels; transacts in nexus (for conduits) and agent (for endpoints) objects; DriverKit network drivers use Skywalk; command line tool: skywalkctl
324
SLC
System-Level Cache, architectural feature of Apple Silicon; cache located within SoC at controllers for external DRAM, serves all compute units and stages transfers between them
325
Social Gaming
Game Center; multiplayer gaming services on top of CloudKit, shared storage and low-latency multicast for multiplayer sessions; launchd service: com.apple.gamed
326
Sock Puppet
Watch interaction that requires Companion deviceWatch interaction that requires Companion iPhone
327
SOS
Secure Object Sync; syncing backend for iCloud Keychain, not to be confused with the emergency call feature; transferred items previously staged in Synced Defaults, for two-factor accounts in CKKS; launchd services: com.apple.secd (access to local keychain), com.apple.security.cloudkeychainproxy3 (connects to Synced Defaults), com.apple.security.keychain-circle-notification
328
SPI
System Private Interface; /System/Library/PrivateFrameworks
329
Splat Update
Rapid Security Response, updates to Cryptex components without system restart
330
SpringBoard
iOS home screen; like Dock (Launchpad, Mission Control, desktop picture), Control Center, SystemUIServer (menu extras icons), loginwindow (lock screen), and WindowServer (compositor) on macOS; /System/Library/CoreServices/SpringBoard.app, /Applications/PreBoard.app, BaseBoard.framework, FrontBoard.framework, SplashBoard.framework; launchd service: com.apple.backboardd (compositor)
331
SPRR
Shadow Permission Remap Register? feature of Apple Silicon to dynamically reintepret page permissions
332
SPTM
Secure Page Table Monitor; code in kernel-level GXF protects page table modifications; Trusted Execution Monitor (TXM) in user-level GXF implements policy and parts of AMFI
333
SRP
Secure Remote Password; standard cryptographic protocol for proving knowledge of a secret such that attackers cannot brute-force the secret; AppleSRP.framework
334
SSO
Single Sign-On
335
SSV
Signed System Volume, als called Authenticated Root Volume (ARV); macOS boots from blessed read-only APFS snapshot, merkle-tree and root-hash stored in Preboot volume; modifications require disabling root authentication with csrutil from recovery, then the live filesystem can be mounted, modified, and re-blessed; command line tools: apfs_systemsnapshot, bless, csrutil
336
Stark
CarPlayCarPlay; iPhone provides video feeds for in-car displays; three layers composited by the car: remote UI (from iPhone), punch-through UI (back up camera), local UI (dashboard gauges: assets from iPhone, rendered by car, like Live Activities?), overlay UI (essential indicators); associate apps on iOS: /Applications/CarCamera.app, /Applications/Charge.app, /Applications/Climate.app, /Applications/Closures.app, /Applications/Media.app, /Applications/TirePressure.app, /Applications/Trip.app, /Applications/Vehicle.app
337
Stockholm
Secure Element in Apple SoCs, a processor running crypto protocols on keys it protects; used for Apple Pay and Car Key; related codenames: Icefall, WarsawSecure Element in Apple SoCs, a processor running crypto protocols on keys it protects; used for Apple Pay and Car Key; related codenames: Icefall, Warsaw; SEService.framework
338
Storage Management
freeing up disk space by managing bulky items; UI in System Information.app; StorageManagement.framework; launchd service: com.apple.diskspaced; extension point: com.apple.storagemanagement; extends Cache Delete service
339
Suggestions
semantic analysis of mails and websites to suggest contacts, calendar events and the like; launchd services: com.apple.suggestd, com.apple.reversetemplated; custom JavaScript parsers in /System/Library/AssetsV2/com_apple_MobileAsset_CoreSuggestions
340
Symbols
debug symbols for backtraces; CoreSymbolication.framework; launchd services: com.apple.coresymbolicationd; command line tools: atos, symbols, symbolscache
341
Symptoms
network diagnostics; Symptoms.framework; /var/networkd/db/netusage.sqlite; launchd service: com.apple.symptomsd (invoked by kernel through host special port 27)
342
Synced Defaults
simple key-value store for applications, no user control over data; can use iCloud key-value backend (old) or Manatee container (new, marked as com.apple.kvs) as storage; launchd service: com.apple.syncdefaultsd; locally stored in ~/Library/SyncedPreferences
343
System Configuration
SystemConfiguration.framework; launchd service: com.apple.configd; command line tool: scutil
344
System Extension
system-wide components formerly implemented as insecure plugins or kexts; current extension types: DriverKit, Network, Endpoint Security, Core Media IO; /System/DriverKit, /System/Library/DriverExtensions; command line tool: systemextensionsctl; launchd services: com.apple.sysextd, com.apple.nesessionmanager, com.apple.endpointsecurity.endpointsecurityd; command line tool: esloggersystem-wide components formerly implemented as insecure plugins or kexts; current extension types: DriverKit, FSKit, Network, Endpoint Security, Core Media IO; /System/DriverKit, /System/Library/DriverExtensions, /Library/Preferences/com.apple.networkextension.plist; command line tool: systemextensionsctl; launchd services: com.apple.sysextd, com.apple.nesessionmanager, com.apple.endpointsecurity.endpointsecurityd; command line tool: eslogger
345
System Policy
Gatekeeper; policy engine for application launches and kext loading, malware signatures from /Library/Apple/System/Library/CoreServices/XProtect.bundle; /var/db/SystemPolicy; launchd service: com.apple.security.syspolicy (invoked by kernel through host special port 29); command line tool: spctlGatekeeper; policy engine for application launches and kext loading, malware signatures from /Library/Apple/System/Library/CoreServices/XProtect.bundle; /var/db/SystemPolicyConfiguration; launchd service: com.apple.security.syspolicy (invoked by kernel through host special port 29); command line tool: spctl
346
Tailspin
sampling of process stack traces; launchd service: com.apple.tailspind; command line tool: tailspin
347
TAL
Transparent App Lifecycle; process for macOS apps started and stopped independently of the user launching and quitting app; also handles session restore across reboots; ~/Library/Saved Application State; launchd service: com.apple.talagent
348
Taskport
Mach kernel concept for ptrace-like access to task internals; access policy implemented by daemon; launchd service: com.apple.taskgated (invoked by kernel through task special port 9); command line tool: DevToolsSecurity
349
TCC
Transparency, Consent, and Control; user control over app access to privacy-related services (kTCCService*); TCC.framework; launchd services: com.apple.tccd, com.apple.tccd.system; command line tool: tccutil; stored in /Library/Application Support/com.apple.TCC, ~/Library/Application Support/com.apple.TCC, /var/db/locationd (for kTCCServiceLocation)
350
Tea
component of Apple’s News, Stocks, and Weather apps, maybe interest personalization? TeaFoundation.framework, TeaDB.framework, TeaUI.framework
351
Template App
code-less app-bundle, passed to an actual executable by LauncServices; created when adding websites in Safari to Dock/Springboard; run by /System/Volumes/Preboot/Cryptexes/App/System/Library/CoreServices/Web App.app
352
Time Machine
automatic backup service, command line tools: tmdiagnose, tmutil
353
Tin Can
Walkie Talkie on watchOSWalkie Talkie on watchOS; /Applications/TinCan.app
354
Tones
ringtones; ToneLibrary.framework
355
Translocation
app binary copied on launch to dedicated location; initiated by Launch Services for security (prevents path traversal for apps quarantined by System Policy) or path normalization (iOS apps do not expect to be moved, but can be moved on macOS)
356
Transparency
key transparency for ESS keys? Transparency.framework; launchd service: com.apple.transparencyd; server: init-kt.apple.comun-alterable append-only log to publish information; used for for ESS keys and PCC software hashes, based on CONIKS, devices audit IDS/PCC records against logs, root hashes gossiped over iMessage to detect split-view attacks; Transparency.framework; launchd service: com.apple.transparencyd; server: init-kt.apple.com
357
TSS
Tatsu Signing Server; online verification for firmware signatures; server: gs.apple.com
358
TTS
Text To Speech, neural-network-based synthesis engine (Gryphon); command line tool: say; /System/Library/Speech, /System/Library/TTSPluginsText To Speech, neural-network-based synthesis engine (Gryphon); command line tool: say; /System/Library/Speech
359
TVML
TV Markup Language; declarative UI language for TV apps; TVMLKit.framework
iCloud Drive; codename Bladerunner, uses CloudKit; CloudDocs.framework; launchd service: com.apple.bird; locally stored in ~/Library/Mobile Documents (was supposed to move to Library/CloudStorage/iCloud Drive but this was reverted)
362
UID
unique ID key, used as root key for cryptographic subsystems, generated during manufacturing by SEP and fused into hardware, only accessible by SEP
363
Unified Logging
system-wide logging and Activity tracking; launchd service: com.apple.logd, com.apple.diagnosticd; command line tool: log; /dev/oslog; data stored in /var/db/diagnostics, support files in /var/db/uuidtext
364
USDUrchin
Universal Scene Description; storage format for 3D assets; /usr/lib/usdTides app on watchOS; /Applications/Urchin.app
365
User ActivityUSD
abstraction for deep-linking into apps with structured context (people, places); used for Universal Links (schema.org on websites), Handoff, Parsec (app links in search), Siri Shortcuts, Quick Note (context awareness), Proactive; UserActivity.framework; launchd service: com.apple.coreservices.useractivitydUniversal Scene Description; storage format for 3D assets; /usr/lib/usd; command line tools: usdcat, usdchecker, usdcrush, usdextract, usdrecord, usdtree, usdzip
366
User Activity
abstraction for deep-linking into apps with structured context (people, places); used for Universal Links (schema.org on websites), Handoff, Parsec (app links in search), Quick Note (context awareness); now part of Intents; UserActivity.framework; launchd service: com.apple.coreservices.useractivityd
367
User Notifications
user interface for notification center; launchd service: com.apple.usernoted
368
UTI
Uniform Type Identifiers; system for document types; file extensions and MIME types are mapped to UTIs, UTIs form a conformance graph, apps register their UTIs with Launch Services; /System/Library/CoreServices/CoreTypes.bundle; also Apple’s hardware devices are represented as UTIs
369
VA
Video Acceleration; AppleGVA.framework, AppleVA.framework, AppleVPA.frameworkVideo Acceleration; AppleVA.framework
370
VDAF
Verifiable Distributed Aggregation Function; part of Differential Privacy; VDAF.framework
371
Viceroy
video conferencing used by FaceTime and ReplayKit; ViceroyTrace.framework
372
Virtualisation
running virtual machines on macOS; Hypervisor.framework (for basic VMs and vCPUs), Virtualization.framework (brings a robust set of device models)
373
VSDB
volume status database; /var/db/volinfo.database; command line tool: vsdbutil
374
Waldo
selects edge servers based on approximate location, part of Private Relay, seen in NSP
375
Wally
private search in server-side database using homomorphic encryption; private information retrieval (PIR), private nearest neighbor search (PNNS); used for Caller ID, email logos, adult website filtering, points-of-interest lookup for photos
376
WFS
WebDAV File Sharing; built-in file sharing with Apache; /etc/wfs; command line tool: wfsctl
377
Widgets
content excerpt from apps; provided via a timeline of view hierarchies, configuration uses Intents; visible on home screen, lock screen, as live activities, as watch complications; WidgetKit.framework; extension point: com.apple.widgetkit-extensioncontent excerpt from apps; provided via a timeline of view hierarchies, configuration uses Intents; visible on home screen, lock screen, as live activities, as watch complications; WidgetKit.framework, ChronoServices.framework; extension point: com.apple.widgetkit-extension; launchd service: com.apple.chronod (timeline management and sync)
378
Willow
HomeKit; end-to-end-encrypted communication protocol and API for IoT-accessories; pairing with SRP using code printed on device, credential sync by CKKS, transported over Alloy, remote access using Apple TV as proxy; launchd service: com.apple.homed
Shortcuts; user-programmable system-wide automation, built-in triggers cause a chain of actions to run; actions are synthesized from User Activities and Intents provided by apps; WorkflowKit.framework, ActionKit.framework; locally stored in ~/Library/Shortcuts; launchd service: com.apple.siriactionsd (voice-triggered shortcuts); command line tool: shortcuts
381
xART
eXtended Anti-Replay Technology; persistent storage for SEP, used by Mesa; /System/Volumes/xarts; launchd service: com.apple.xartstorageremoted; command line tool: xartutil
382
XCS
Xcode Server; continuous integration server; command line tools: xcscontrol, xcsdiagnose
383
XProtect
signature-based malware scanner and remediation service; /Library/Apple/System/Library/CoreServices/XProtect.bundle; command line tool: xprotect
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