66 lines
2.4 KiB
ReStructuredText
66 lines
2.4 KiB
ReStructuredText
.. _about_zephyr:
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Introduction to the Zephyr Project
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##################################
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The Zephyr Kernel is a small-footprint kernel designed for use on
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resource-constrained systems: from simple embedded environmental
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sensors and LED wearables to sophisticated smart watches and IoT
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wireless gateways.
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It is designed to be supported by multiple architectures, including
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ARM Cortex-M, Intel x86, and ARC. The full list of supported platforms
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can be found :ref:`here <board>`.
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Licensing
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*********
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The Zephyr project associated with the kernel makes it available
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to users and developers under the Apache License, version 2.0.
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Distinguishing Features
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***********************
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The Zephyr Kernel offers a number of features that distinguish it from other
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small-footprint OSes:
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#. **Single address-space OS**. Combines application-specific code
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with a custom kernel to create a monolithic image that gets loaded
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and executed on a system's hardware. Both the application code and
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kernel code execute in a single shared address space.
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#. **Highly configurable**. Allows an application to incorporate *only*
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the capabilities it needs as it needs them, and to specify their
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quantity and size.
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#. **Resources defined at compile-time**. Requires all system resources
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be defined at compilation time, which reduces code size and
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increases performance.
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#. **Minimal error checking**. Provides minimal run-time error checking
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to reduce code size and increase performance. An optional error-checking
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infrastructure is provided to assist in debugging during application
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development.
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#. **Extensive suite of services** Offers a number of familiar services
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for development:
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* *Multi-threading Services* for both priority-based, non-preemptive
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fibers and priority-based, preemptive tasks with optional round robin
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time-slicing.
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* *Interrupt Services* for both compile-time and run-time registration
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of interrupt handlers.
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* *Inter-thread Synchronization Services* for binary semaphores,
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counting semaphores, and mutex semaphores.
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* *Inter-thread Data Passing Services* for basic message queues, enhanced
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message queues, and byte streams.
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* *Memory Allocation Services* for dynamic allocation and freeing of
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fixed-size or variable-size memory blocks.
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* *Power Management Services* such as tickless idle and an advanced idling
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infrastructure.
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