Digital Twin
A server-side model of a physical thing's reported and desired state.
4 to work through
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intermediate Multiple choice
A building-controls platform stores a desired state per device and reconciles it on every connection. An operator sets a fan setpoint that one hardware revision cannot accept, and applies it in bulk to 40,000 units. The platform compares reported state with desired state to decide whether to act. What happens over the next day, and which single change stops it?
2 min answer -
intermediate Multiple choice
A field device is offline for hours at a time, and operators change its settings while it is away - sometimes twice. What should the platform store?
2 min answer -
intermediate
What problem does a digital twin actually solve, and when is it over-engineering?
1 min answer -
advanced
A team proposes a digital-twin platform for 20,000 HVAC units: every sensor reading and every attribute change written to an event-sourced graph database with full per-attribute version history, a rules engine evaluating 400 conditions per device per minute, and a 3D visualisation of each site. The goal is "predictive maintenance and remote diagnostics". Review it. What would you remove, what would you change, and what would you leave alone?
3 min answer
3 terms in this topic
Device Shadow
A cloud-side representation of a device's last reported state and its intended state, letting applications interact with devices that are asleep or o…
practiceExplicit Staleness
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 c…
patternReported Versus Desired State
Holding two representations of a device — what it last said it was, and what it should be — with the gap between them driving reconciliation.
Neighbouring topics
Edge, Mobile & IoT
General material on architecture beyond the data centre boundary.
Mobile App Architecture
Layering, navigation, background execution, and the platform rules you do not set.
Offline-First
Treating connectivity as an optimisation, with a local store as the source of truth.
Sync & Conflict Resolution
Two devices that both changed the same record while neither could see the other.
CRDTs
Data types that converge without coordination, and the semantics you must accept.
Mobile Release Strategy
Store review, staged rollout, and supporting versions you can never force off.
Push & Background Work
Delivery that is best-effort, and an operating system that will kill your process.
Device Identity
Identifying a thing rather than a person, and rotating a credential you cannot type.
Edge Compute Topologies
Regional, metro, on-premises and on-device, and what each tier is genuinely for.
Edge Functions
Short-lived compute at the CDN, its runtime limits, and what must stay at origin.
Edge Data Consistency
Replicated read state at hundreds of locations, and writes that still go to one.
IoT Ingest Architecture
Millions of small, unreliable, frequently duplicated messages arriving continuously.
Device Provisioning
Getting identity and configuration onto hardware at manufacture or first boot.
Fleet Management
Inventory, health, configuration and grouping across devices you will never see.
OTA Updates
Updating firmware over a flaky link, with rollback, and without bricking the device.
Constrained Protocols
MQTT, CoAP and their kin, chosen for power, packet size and intermittent links.
Device Telemetry at Scale
Deciding what a device sends, how often, and what is aggregated before it leaves.
Edge Security & Attestation
Secure boot, hardware roots of trust, and proving what is running on a device.
Physical-World Failure Modes
Power loss, tampering, clock drift, thermal limits, and a truck through the fibre.