9.2. Review of Disk I/O Concepts
The Unix operating system sees all input to and output from the CPU as a matter of reading from or writing to files. Disk files are one specific type of I/O governed by the same rules and using the same I/O stack as all the I/O operations. This stack, as it applies to disk devices, is shown in Figure 9-3.
Figure 9-3. I/O Stack
The application code makes system calls to the I/O subsystem, specifying what is to be opened, closed, read, or written as a filename. The filename determines the type of object that is opened and accessed. Object types include whole disks, disk sections, or LVM volumes. I/O types used to ...