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 song recognition and matching with Apple catalog, playback on HomePod; /System/Library/Components/AudioDSP.component
@@ -12,7 +13,7 @@ Activation cryptographic check-in with iCloud to lock devices reported by the us
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
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
@@ -50,9 +51,9 @@ Attestation cryptographic proof of a genuine SEP; used for web authentication an
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 tools: avbanalyse, avbdiagnose, avbutil
AWD Apple Wireless Diagnostics, sends system telemetry to Apple; CoreAnalytics.framework, WirelessDiagnostics.framework; launchd services: com.apple.awdd, com.apple.analyticsd
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
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
@@ -69,6 +70,7 @@ Cache Delete cleanup for various caches; /System/Library/CacheDelete; launchd se
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
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
@@ -77,6 +79,7 @@ Chamois Stage Manager
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 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)
@@ -132,26 +135,25 @@ Family Circle Family Sharing; launchd services: com.apple.familycircled, com.app
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? used for emoji, Suggestions, Dictation; /System/Library/DistributedEvaluation; DistributedEvaluation.framework, FedStats.framework (private federated learning?); 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, 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 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; used for JIT protection and by AMFI to freeze user code after checking
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
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 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; command line tool: csfdiagnose (cloud subscription features)
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; GroupKit.framework; launchd service: com.apple.groupkitd
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
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
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; launchd service: com.apple.oahd
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
@@ -282,7 +285,7 @@ Replicator notification sync from Companion iPhone, also drives remotely display
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
SBPL Sandbox Profile Language; a TinyScheme-based embedded DSL for Seatbelt profiles
@@ -293,7 +296,7 @@ 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, Blackbeard.framework (personalisation and workout programs)
SF Symbols scalable UI symbols; rendered with various color treatments; SFSymbols.framework
@@ -319,11 +322,11 @@ SOS Secure Object Sync; syncing backend for iCloud Keychain, not to be confused
SPI System Private Interface; /System/Library/PrivateFrameworks
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 with higher-than-kernel privileges (Trustzone Monitor?) protects page table modifications; deprivileged Trusted Execution Monitor (TXM) implements policy; successor to FPR/SPRR?
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; 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/AutoSettings.app, /Applications/CarCamera.app, /Applications/Charge.app, /Applications/Climate.app, /Applications/Closures.app, /Applications/Media.app, /Applications/TirePressure.app, /Applications/Trip.app
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
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
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)
@@ -355,12 +358,13 @@ USD Universal Scene Description; storage format for 3D assets; /usr/lib/usd; com
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, 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
1
Term
Description
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
song recognition and matching with Apple catalog, playback on HomePod; /System/Library/Components/AudioDSP.component
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 palletizationApple 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
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 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-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
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
CBOR
Concise 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
79
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
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 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)
135
FDE
Full Disk Encryption, FileVault; command line tool: fdesetup, sysadminctl
136
FDR
Factory Data/Device Reset? ensures that no downgrades are performed? servers: skl.apple.com, gg.apple.com; /System/Library/FDR
137
Feldspar
Apple News; Silex.framework
138
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?); 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?)
139
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
140
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
141
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
142
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
143
FollowUp
user interaction for Secure Backup wrapping with device passcode, CoreFollowUp.framework; launchd service: com.apple.followupd
144
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
145
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
146
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
147
FUD
Firmware Update Daemon; see TSS, UARP; launchd service: com.apple.accessoryupdaterd
148
Game Mode
auto-activates when games are shown full screen, throttles background work, lowers audio and input latency; launchd service: com.apple.gamepolicyd
149
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
150
Gizmo
Apple Watch; watch settings managed by Companion iPhone; /Applications/Bridge.app, /System/Library/BridgeManifests
151
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; command line tool: csfdiagnose (cloud subscription features)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
152
Group Activities
SharePlay; sharing of media content and programmatic state over FaceTime calls; GroupActivities.framework, CopresenceCore.framework; launchd service: com.apple.telephonyutilities.callservicesd
153
GroupKit
groups of IDS users with shared CloudKit (PCS) access; GroupKit.framework; launchd service: com.apple.groupkitdgroups of IDS users with shared CloudKit (PCS) access; GroupKitCrypto.framework
154
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
155
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
156
HAP
Home Automation Protocol; CoreHAP.framework
HDA
High Definition Audio; HDAInterface.framework
157
HDI
Hard Disk Image; command line tool: hdiutil
158
HeadBoard
derivative of SpringBoard for tvOS home screen; /Applications/HeadBoard.app, /Applications/PineBoard.app
159
Health Balance
vitals app on Watch; /Applications/NanoHealthBalance.app
224
Nano
prefix for watchOS
225
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
226
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
230
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
231
Noticeboard
User Notifications for Software Update and App Store, Noticeboard.framework; launchd services: com.apple.noticeboard.state (nbstated), com.apple.noticeboard.agent (nbagent)
232
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
233
NSP
Network Service Proxy; per-app VPN and proxy settings, implements Private Relay; launchd service: com.apple.networkserviceproxy
234
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; launchd service: com.apple.oahdRosetta; 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
235
ODR
On-Demand Resources; loaded from App Store; launchd service: com.apple.appstored
236
Omni Search
fuzzy semantic search with results recognized in images; OmniSearch.framework
237
Onboarding
data protection splash screen shown by service-connected apps; /System/Library/OnBoardingBundles; OnBoardingKit.framework
285
Revisions
document autosave and auto-versioning; stored in .DocumentRevisions-V100; GenerationalStorage.framework; launchd service: com.apple.revisiond
286
Routine
frequently visited locations on iOS, interacts with Duet; launchd service: com.apple.routined
287
RTC
Real-time Telemetry and Crash reporting; RTCReporting.framework; launchd service: com.apple.rtcreportingd
288
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
289
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
290
Safety Monitor
Check In; short-term location sharing in iMessage until a destination is reached; /Applications/SafetyMonitorApp.app
291
SBPL
Sandbox Profile Language; a TinyScheme-based embedded DSL for Seatbelt profiles
296
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
297
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)
298
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
299
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
300
Sequoia
translation; downloadable language models can run on-device; /Applications/SequoiaTranslator.app, Translation.framework
301
Seymour
Apple Fitness+; workout videos integrated with Watch sensors; SeymourCore.framework, Blackbeard.framework (personalisation and workout programs)
302
SF Symbols
scalable UI symbols; rendered with various color treatments; SFSymbols.framework
322
SPI
System Private Interface; /System/Library/PrivateFrameworks
323
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)
324
SPRR
Shadow Permission Remap Register? feature of Apple Silicon to dynamically reintepret page permissions
325
SPTM
Secure Page Table Monitor; code with higher-than-kernel privileges (Trustzone Monitor?) protects page table modifications; deprivileged Trusted Execution Monitor (TXM) implements policy; successor to FPR/SPRR?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
326
SRP
Secure Remote Password; standard cryptographic protocol for proving knowledge of a secret such that attackers cannot brute-force the secret; AppleSRP.framework
327
SSO
Single Sign-On
328
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
329
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/AutoSettings.app, /Applications/CarCamera.app, /Applications/Charge.app, /Applications/Climate.app, /Applications/Closures.app, /Applications/Media.app, /Applications/TirePressure.app, /Applications/Trip.appCarPlay; 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
330
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
331
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
332
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
347
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)
348
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
349
TSS
Tatsu Signing Server; online verification for firmware signatures; server: gs.apple.com
350
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
351
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)
358
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
359
User Notifications
user interface for notification center; launchd service: com.apple.usernoted
360
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
361
VA
Video Acceleration; AppleGVA.framework, AppleVA.framework, AppleVPA.frameworkVideo Acceleration; AppleVA.framework
362
VDAF
Verifiable Distributed Aggregation Function; part of Differential Privacy; VDAF.framework
363
Viceroy
video conferencing used by FaceTime and ReplayKit; ViceroyTrace.framework
364
Virtualisation
running virtual machines on macOS; Hypervisor.framework (for basic VMs and vCPUs), Virtualization.framework (brings a robust set of device models)
365
VSDB
volume status database; /var/db/volinfo.database; command line tool: vsdbutil
366
Waldo
selects edge servers based on approximate location, part of Private Relay, seen in NSP
367
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
368
WFS
WebDAV File Sharing; built-in file sharing with Apache; /etc/wfs; command line tool: wfsctl
369
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)
370
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
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