The Linux SCSI Sub-System
The Linux SCSI sub-system is split into 3 layers:
Originally written by
- SCSI low-layer - contains the HBA drivers for the different vendors.
- SCSI mid-layer - a single driver that allows HBA drivers and upper-layer
drivers to find each other, and supports operations common to all
- SCSI upper-layer - contains devices for different device types:
- sd - a block driver for SCSI disks.
- st - a character driver for SCSI tapes.
- sr - a block driver for SCSI CDs/DVDs.
- sg - a generic character driver - used to bypass the above drivers,
or to talk to other types of devices, such as scanners.