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 | .. _glossary: | 
 |  | 
 | Glossary of Terms | 
 | ################# | 
 |  | 
 | .. glossary:: | 
 |    :sorted: | 
 |  | 
 |    API | 
 |       (Application Program Interface) A defined set of routines and protocols for | 
 |       building application software. | 
 |  | 
 |    application | 
 |       The set of user-supplied files that the Zephyr build system uses | 
 |       to build an application image for a specified board configuration. | 
 |       It can contain application-specific code, kernel configuration settings, | 
 |       and at least one CMakeLists.txt file. | 
 |       The application's kernel configuration settings direct the build system | 
 |       to create a custom kernel that makes efficient use of the board's | 
 |       resources. | 
 |       An application can sometimes be built for more than one type of board | 
 |       configuration (including boards with different CPU architectures), | 
 |       if it does not require any board-specific capabilities. | 
 |  | 
 |    application image | 
 |       A binary file that is loaded and executed by the board for which | 
 |       it was built. | 
 |       Each application image contains both the application's code and the | 
 |       Zephyr kernel code needed to support it. They are compiled as a single, | 
 |       fully-linked binary. | 
 |       Once an application image is loaded onto a board, the image takes control | 
 |       of the system, initializes it, and runs as the system's sole application. | 
 |       Both application code and kernel code execute as privileged code | 
 |       within a single shared address space. | 
 |  | 
 |    board | 
 |       A target system with a defined set of devices and capabilities, | 
 |       which can load and execute an application image. It may be an actual | 
 |       hardware system or a simulated system running under QEMU. | 
 |       The Zephyr kernel supports a :ref:`variety of boards <boards>`. | 
 |  | 
 |    board configuration | 
 |       A set of kernel configuration options that specify how the devices | 
 |       present on a board are used by the kernel. | 
 |       The Zephyr build system defines one or more board configurations | 
 |       for each board it supports. The kernel configuration settings that are | 
 |       specified by the build system can be over-ridden by the application, | 
 |       if desired. | 
 |  | 
 |    IDT | 
 |       (Interrupt Descriptor Table) a data structure used by the x86 | 
 |       architecture to implement an interrupt vector table. The IDT is used | 
 |       to determine the correct response to interrupts and exceptions. | 
 |  | 
 |    ISR | 
 |       (Interrupt Service Routine) Also known as an interrupt handler, an ISR | 
 |       is a callback function whose execution is triggered by a hardware | 
 |       interrupt (or software interrupt instructions) and is used to handle | 
 |       high-priority conditions that require interrupting the current code | 
 |       executing on the processor. | 
 |  | 
 |    kernel | 
 |       The set of Zephyr-supplied files that implement the Zephyr kernel, | 
 |       including its core services, device drivers, network stack, and so on. | 
 |  | 
 |    XIP | 
 |       (eXecute In Place) a method of executing programs directly from long | 
 |       term storage rather than copying it into RAM, saving writable memory for | 
 |       dynamic data and not the static program code. |