Summary

This chapter began with an overview of device drivers, including details on the instruction sequences used by driver code to read from and write to a simple I/O device, the PC parallel port. We continued with a discussion of the legacy BIOS and the newer UEFI, which provide the code that first executes on PC power-up, performs device testing and initialization, and initiates loading of the operating system.

We continued with a description of some of the fundamental elements of operating systems, including processes, threads, and the scheduler. Various scheduling algorithms used in past computers and the systems of today were introduced. We examined the output of tools available in Windows and Linux that present information about running processes.

The chapter concluded with a discussion of multiprocessing and its performance impact on the computer systems of today, as well as the implications of MIMD and SIMD parallel processing for the future of computing.

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