April 2012
Intermediate to advanced
352 pages
8h
English
Content preview from FreeBSD Device Drivers
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Chapter 13. Storage Drivers
In FreeBSD, storage drivers provide access to devices that transfer randomly accessible data in blocks (such as disk drives, flash memory, and so on). A block is a fixed-size chunk of data (Corbet et al., 2005). In this chapter I’ll discuss how to manage devices that employ block-centric I/O. To that end, some familiarity with disk and bio structures is needed, so that is where we’ll start.
disk Structures
A disk structure is the kernel’s representation of an individual disk-like storage device. It is defined in the <geom/geom_disk.h> header as follows:
struct disk { /* GEOM Private Data */ struct g_geom *d_geom; struct ...