Term Kind Topic What it is
A/B Partition Update Dual-Bank Update, Seamless Update pattern OTA Updates Writing a new device image to an inactive partition and switching to it only after verification, so that a failed update falls back to the known-good image instead of bricking the device.
A/B Partition Update pattern OTA Updates Writing firmware to an inactive partition and switching on next boot, so a failed update falls back to the previous image rather than bricking the device.
Attestation Freshness Nonce-Bound Quote, Replay-Resistant Attestation concept Edge Security & Attestation The property that a hardware attestation can only be used in the exchange that requested it - without which a captured measurement is a reusable bearer token for the whole fleet.
Attestation Transparency Log Verifiable Transparency, Published Measurement Log pattern Edge Security & Attestation A public append-only log of every software measurement a fleet is allowed to run, checked by the client before it sends data, which removes the possibility of a build served to one user only.
Background Work on Mobile concept Push & Background Work Work scheduled outside the foreground session, which mobile operating systems aggressively restrict to protect battery life.
Backhaul Cost per Device-Day Bytes per Device-Day, Per-Device Data Budget metric Constrained Protocols The bytes a single device sends and receives in a day multiplied by the price of the link - the figure that converts a sampling decision into a line in the connectivity contract.
Best Effort Delivery concept Push & Background Work The guarantee push notification services actually offer — which is none — and the design consequences of building on a channel that may silently drop.
Claim-Code Binding Device Claiming, Ownership Binding, Claim on First Use pattern Device Provisioning Giving a device its cryptographic identity at manufacture but its owner at first use, so the factory line never depends on the cloud and ownership can be transferred without re-keying.
Clock Drift concept Physical-World Failure Modes Device clocks diverging from real time, which corrupts ordering, expires certificates early or late, and produces data that appears to arrive from the past.
Cloudflare Workers: Isolates Instead of Containers V8 Isolates case-study Edge Functions Running thousands of tenants per process using V8 isolates rather than containers, trading runtime flexibility for near-zero cold start and extreme density.
Cold Start at the Edge concept Edge Functions The initialisation delay when a request reaches a location with no warm instance, which at the edge occurs far more often because traffic is spread across many locations.
Command Validity Window Command Expiry, Time-Bounded Actuation practice Fleet Management An expiry attached to a command sent to a device, so that an instruction delivered after the situation has changed is discarded rather than executed.
Compute Tier Placement concept Edge Compute Topologies Deciding which of on-device, on-premises, metro, regional or central compute a workload belongs to, from its latency, data volume and autonomy requirements.
Conflatable Classification Superseding vs Discrete Events, What May Be Dropped practice Device Telemetry at Scale Explicitly classifying each telemetry stream as superseding or discrete, because conflation is the correct overload behaviour for one and silent data loss for the other.
Conflict Copy Conflicted Version, Both-Sides Preservation pattern Sync & Conflict Resolution Preserving both sides of a sync conflict as separate artefacts rather than choosing a winner - the only resolution strategy that never loses user work.
Constrained Protocol MQTT, CoAP, LwM2M protocol Constrained Protocols Messaging protocols designed for devices and networks where power, bandwidth and packet size are hard limits rather than considerations.
Convergence Without Coordination concept CRDTs The property that replicas applying the same set of updates in any order reach the same state, which is what removes the need for a central arbiter.
CRDT Conflict-Free Replicated Data Type concept CRDTs A data structure whose concurrent updates always merge to the same result regardless of order, removing the need for coordination or conflict resolution.
Device Group Rollout practice Fleet Management Applying configuration or firmware to a fleet in ordered cohorts with health checks between them, because a bad change applied to everything at once has no remedy.
Device Identity concept Device Identity Establishing and maintaining a trustworthy identity for each device in a fleet — including the parts that must work for a decade without physical access.
Device Provisioning practice Device Provisioning Giving a device a unique cryptographic identity and its initial configuration in a way that scales to millions and survives a hostile supply chain.
Device Shadow Digital Twin, Reported and Desired State pattern Digital Twin A cloud-side representation of a device's last reported state and its intended state, letting applications interact with devices that are asleep or offline.
Device Telemetry at Scale concept Device Telemetry at Scale The volume problem created by many devices each emitting small frequent messages, where the answer is filtering at the edge rather than ingesting everything.
Device-Side Refusal Local Precondition Check, The Device Decides concept OTA Updates The rule that a device must refuse an unsafe instruction regardless of what the server commanded, because the server does not know the device's physical state.
Edge Aggregation pattern Device Telemetry at Scale Summarising or filtering telemetry at the device or gateway so that only what is needed leaves, which is usually the difference between a viable and an unaffordable design.
Edge Compute Topology concept Edge Compute Topologies The choice of where computation sits along the path from device to region, trading latency and autonomy against manageability and consistency.
Edge Data Consistency concept Edge Data Consistency The consistency model available when data is replicated to many edge locations, where strong consistency would eliminate the latency benefit that motivated the edge.
Edge Functions tool Edge Functions Small units of code executed at points of presence near users — powerful for stateless work, constrained by the limits of the runtime and the difficulty of state.
Edge Security and Attestation concept Edge Security & Attestation Establishing that a device is running expected software and has not been tampered with — the trust foundation when you do not control the physical environment.
Edge Triage On-Device Filtering, Selective Collection, Interesting-Event Upload pattern Fleet Management Deciding on the device which data is worth transmitting, because a fleet generates far more than any network can carry - and the common, uneventful case is also the least valuable.
Edge, Mobile and IoT concept Edge, Mobile & IoT Architectures where compute sits on devices or near users — sharing the constraints of intermittent connectivity, limited resources and clients you cannot upgrade.
Exception Path Frequency Normal Exceptions, Physical Divergence Rate metric Physical-World Failure Modes The rate at which physical operations diverge from the system's model - a business metric to be managed rather than a defect rate to be eliminated, and the input to how the exception path should be resourced.
Explicit Staleness As-Of Semantics, Freshness Disclosure practice Digital Twin Publishing how old a modelled or cached value is alongside the value itself, so consumers can judge whether it is usable rather than assuming it is current.
Fleet Management practice Fleet Management Operating a large population of physical devices — knowing what is deployed, where, on which version, in what health, and acting on that at scale.
Fleet Reconnection Storm Device Thundering Herd, Synchronised Reconnect, IoT Recovery Surge concept Device Telemetry at Scale A synchronised burst of devices re-establishing connections after any disruption, which is far more expensive than steady-state traffic and routinely turns a brief platform blip into a prolonged outage.
Forced Upgrade practice Mobile Release Strategy Blocking an installed client version from operating until it updates, which is the only lever available and is disruptive enough to need a policy.
Hardware Backed Credential concept Device Identity A private key generated inside a secure element and unable to leave it, so device identity cannot be copied off the device.
Ingest Fan-In concept IoT Ingest Architecture The shape of a system receiving many small messages from very many senders, where connection count rather than data volume is the primary constraint.
Invalid-Clock Boot Epoch Boot, Clock-Zero Boot, Time-Before-Trust Problem concept Physical-World Failure Modes A device booting with no trustworthy notion of time, which makes certificate validity unverifiable and creates a dependency loop - correct time needs a trusted connection and a trusted connection needs correct time.
IoT Ingest Architecture pattern IoT Ingest Architecture Receiving high-volume telemetry from a large device fleet — where connection count, backpressure and reconnection storms dominate the design.
Last Writer Wins pattern Sync & Conflict Resolution Resolving a conflict by keeping the version with the later timestamp — simple, deterministic, and it silently discards the other change.
Local First Write pattern Offline-First Committing to local storage first and treating the server as an eventual replica, which makes the interface responsive and connectivity an optimisation.
Local Revert On-Device Rollback, A/B Partition Update, Watchdog Revert pattern OTA Updates A device automatically returning to its previous known-good software or configuration when the new one fails, without needing to contact a server - the only mechanism that works when the failure prevents commu…
Message Overhead Budget concept Constrained Protocols The proportion of each transmission spent on protocol rather than payload, which on a metered or battery-powered link determines the running cost.
Mobile App Architecture concept Mobile App Architecture Client architecture where the release cycle is not yours, old versions persist indefinitely, and the network is unreliable.
Mobile Release Strategy practice Mobile Release Strategy Shipping to an app store where review adds latency, users choose when to update, and old versions therefore stay live indefinitely.
Offline-First Architecture pattern Offline-First Treating the local device store as the primary source the application reads and writes, with the network as an asynchronous replication channel.
Over-the-Air Update OTA, Firmware Update practice OTA Updates Updating software on deployed physical devices remotely, where a failed update can require someone to physically visit the device.
Per-Device Series Budget Fleet Series Count, Device-Tag Cardinality Limit metric Device Telemetry at Scale The number of distinct metric time series a fleet creates - series per device multiplied by device count - which decides observability cost long before data volume does, and which determines whether per-device…
Physical World Failure Mode concept Physical-World Failure Modes The failure classes that only exist once software controls or observes physical equipment, where the system cannot be restarted and the consequences are not confined to data.
Platform Lifecycle Constraint concept Mobile App Architecture The operating system's rules about when your process runs, which are not negotiable and invalidate most assumptions carried over from server code.
Push Token Decay Stale Registration Token, Push Target Rot concept Push & Background Work The steady accumulation of push targets that no longer reach a device - which inflates fan-out cost and makes delivery metrics describe a list rather than an audience.
Radio Wake Budget Transactions Per Day Budget, Wake Count Budget metric Constrained Protocols The number of radio wakes a device can afford per day at its target battery life - the planning number that decides protocol and batching choices, because energy is spent per transmission rather than per byte.
Read Local Write Global pattern Edge Data Consistency Replicating read-only state to every edge location while directing writes to a single authoritative region, which is the arrangement most edge data stores actually provide.
Remote Resolvability Issues Fixable Without a Visit, Field Visit Rate metric Fleet Management The proportion of device issues that can be diagnosed and resolved without a physical visit - a design-time property that determines the operating cost of a fleet for its entire life.
Reported Versus Desired State pattern Digital Twin Holding two representations of a device — what it last said it was, and what it should be — with the gap between them driving reconciliation.
Resync Horizon Tombstone Retention Window, Full Resync Threshold concept Sync & Conflict Resolution The age of the oldest change a server can still describe as a delta - beyond which a returning client must take a full snapshot or it will silently keep records that were deleted.
Secure Boot Chain protocol Edge Security & Attestation Each boot stage verifying the signature of the next before executing it, anchored in immutable hardware, so only authorised software runs.
Sensor Input Validation Telemetry Plausibility Checking, Physical Input Sanitisation practice Physical-World Failure Modes Treating readings from physical devices as untrusted input requiring plausibility checks - because a sensor that fails toward a well-formed wrong value is far more damaging than one that stops reporting.
Server-Driven UI Backend-Driven UI, Remote Screen Definition pattern Mobile Release Strategy Describing screens as data returned by the server and rendered by native components - removing the app-store release from the change loop, in exchange for a permanent compatibility contract with every version …