30 lines
1.6 KiB
ReStructuredText
30 lines
1.6 KiB
ReStructuredText
.. _system_fundamentals:
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System Fundamentals
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###################
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An :dfn:`application image` is a binary that controls the operation
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of a hardware system, or of a simulated system running under QEMU.
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Each application image contains both the application's code and the Zephyr
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kernel code needed to support it. They are compiled as a single,
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fully-linked binary.
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Once an application image has been loaded onto a target system, the image takes control
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of the system, initializes it, and runs forever as the system's sole application.
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Both application code and kernel code execute as privileged code within a single
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shared address space.
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An :dfn:`application` is a set of user-supplied files that the Zephyr build
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system processes to generate an application image. The application consists of
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application-specific code, a collection of kernel configuration settings, and at
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least one Makefile. The application's kernel configuration settings enable the build
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system to create a kernel tailor-made to meet the needs of the application
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and to make the best use of the system's resources.
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The Zephyr Kernel supports a variety of target systems, known as *platforms*;
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each :dfn:`platform` has its own set of hardware devices and capabilities. One or more
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*platform configurations* are defined for a given platform; each
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:dfn:`platform configuration` indicates how the devices that may be present on the
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platform are to be used by the kernel. The platform and platform configuration concepts
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make it possible to develop a single application that can be used by a set of related
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target systems, or even target systems based on different CPU architectures. |