Chapter 6I/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 moving-head disk drives, magnetic-tape drives, and network interfaces. Storage devices such as disks and tapes are accessed through I/O controllers that manage the operation of their slave 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 ...