Core concepts

This page briefly introduces the key concepts needed to understand JelinaOS. You do not need to memorize them all—return here as a reference while reading other chapters.

A/B partitions

The core reliability design in JelinaOS. Both the kernel and system have two complete copies, A and B, with only one set used at runtime:

• The two copies provide mutual backup, both in their factory state.
• System updates write only to the inactive copy; switching occurs after the update completes and passes validation.
• If the new version has problems, you can revert to the other copy at any time.

For users, A/B partitions mean upgrades with a recovery path instead of a gamble.

Read-only system

At runtime, the system partition is mounted read-only, preventing any program from changing its contents. This is the foundation of system security: even with application faults or accidental operations, the system itself remains intact.

Data partition

A separate partition holds all user data and write operations:

• User files, configuration, and application data are stored here.
• System updates and factory resets do not affect the data partition itself. A factory reset does restore the system and user-written data to their factory state, so back up important data first.
• The data partition and system partition are physically isolated and do not interfere with each other.

Update mechanism (OTA)

JelinaOS supports online updates (OTA) for four categories: the system, kernel, device agent, and incremental updates:

• Cloud OTA: Centrally orchestrated by JelinaCloud, with batch delivery and staged execution.
• Local OTA: Updates through device-side tools for offline or locally controlled environments.
• Incremental updates (Increment): Transfer only changes to save bandwidth and shorten update times, suitable for sites with limited bandwidth.

Device agent (Jelinvisor)

The management component running on each device bridges the device and JelinaCloud:

• Handles device registration, status reporting, and update execution.
• Manages the lifecycle of containerized and non-containerized applications.
• Provides local interfaces for on-site management and diagnostics.

Applications and releases

• Containerized application: An application delivered as a container image, providing a consistent environment and simple deployment.
• Non-containerized application (ProgramSet): A traditional program running as a service, with declarative configuration and system-level management.
• Release: A collection of applications and configurations created in the cloud and deployed to devices; the basic unit of updates and version management.

Fleet

A unit for grouping and managing devices in JelinaCloud. Devices in the same fleet can:

• Use a centrally specified release version.
• Receive batch system, kernel, and agent updates.
• Share centrally configured runtime policies.

Operating modes

The device agent supports several operating modes for different deployment environments:

Mode	Use case	Characteristics
Cloud-managed	Standard JelinaCloud deployment	Registration, reporting, and cloud command reception
Locally managed	Environments without a cloud or on isolated private networks	Device management through local interfaces
Offline	Temporary network disconnection	Retains cloud configuration and suspends network activity
Standalone	Deployments entirely without cloud connectivity	Local device self-management without cloud dependencies

Quick reference

Concept	Brief explanation
A/B partitions	Two system copies provide a recovery path for updates
Read-only system	System contents cannot be modified
Data partition	Separate storage for user data
OTA	Online updates executed from the cloud or locally
Incremental update	Efficient update that transfers only changes
Device agent	Bridge between device and cloud
Release	Deployment unit for applications and configuration
Fleet	Unit for grouping and managing devices