Drivers for Block Devices

This chapter describes the structure of block device drivers. The kernel views a block device as a set of randomly accessible logical blocks. The file system uses a list of buf(9S) structures to buffer the data blocks between a block device and the user space. Only block devices can support a file system.

This chapter provides information on the following subjects:

• Block Driver Structure Overview

• File I/O

• Block Device Autoconfiguration

• Controlling Device Access

• Synchronous Data Transfers (Block Drivers)

• Asynchronous Data Transfers (Block Drivers)

• dump() and print() Entry Points

• Disk Device Drivers