دانلود کتاب توسعه سفت افزار – راهنمای دانش تخصصی سیستم

Firmware is the first piece of code that runs on the target hardware after the end user has turned on a device. Depending on the types of target hardware, the operations being performed by the firmware may differ, but the fundamental operations of firmware remain the same across the target hardware: performing the bare minimal hardware initialization and either waiting for host-centric communication to initiate or handing off control to the high-level system software that allows the end-user interaction. Based on the target market segment, an OS can have multiple virtual machines, and/or various types of applications are installed that satisfy the end-user needs. Although the control goes to the OS, an instance of the firmware is still alive and available to manage a few critical tasks that for OS-based applications or drivers cannot perform.

Over time, CPU architectures have gotten more complicated, and platform requirements have evolved. This has pushed the firmware boundary and caused firmware to extend its services too.