Chapter 6. I/O System Overview

6.1 I/O Mapping from User to Device

Computers store and retrieve data through supporting peripheral I/O devices. These devices typically include mass-storage devices, such as disk drives, archival-storage devices, and network interfaces. Storage devices such as disks are accessed through I/O controllers that manage the operation of their attached devices according to I/O requests from the CPU.

Many hardware device peculiarities are hidden from the user by high-level kernel facilities, such as the filesystem and socket interfaces. Other such peculiarities are hidden from the bulk of the kernel itself by the I/O system. The I/O system consists of buffer-caching systems, general device-driver code, and ...

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