Take notes on the drive part of the block device.

Transferred from: Http://bbs.chinaunix.net/thread-2050601-1-1.html For Block devices, first define several basic concepts: Sector (sectors): Usually 512 bytes. It is the basic unit for hardware devices to transmit data. Block (blocks): usually 1, 2, 4, 8,... slice, and smaller than one page. It is the basic unit for the kernel (VFS and file system) to transmit data. Segment: it is a number of adjacent blocks. It is a part of a memory page or memory page. It is generally driven by Block devices.ProgramTo process. Each buffer corresponds to a block, which is equivalent to the representation of the disk block in the memory. Reference a graph in ulk3 to illustrate their relationship: Upload from Download Attachment (21.3 KB) For the layered architecture of the entire block device driver, a figure in ulk3 can clearly describe these: Upload from Download Attachment (23.6 KB)