|SCSI subsystem documentation
|The Linux Documentation Project (LDP) maintains a document describing
|the SCSI subsystem in the Linux kernel (lk) 2.4 series. See:
|http://www.tldp.org/HOWTO/SCSI-2.4-HOWTO . The LDP has single
|and multiple page HTML renderings as well as postscript and pdf.
|It can also be found at http://www.torque.net/scsi/SCSI-2.4-HOWTO .
|Notes on using modules in the SCSI subsystem
|The scsi support in the linux kernel can be modularized in a number of
|different ways depending upon the needs of the end user. To understand
|your options, we should first define a few terms.
|The scsi-core (also known as the "mid level") contains the core of scsi
|support. Without it you can do nothing with any of the other scsi drivers.
|The scsi core support can be a module (scsi_mod.o), or it can be built into
|the kernel. If the core is a module, it must be the first scsi module
|loaded, and if you unload the modules, it will have to be the last one
|unloaded. In practice the modprobe and rmmod commands (and "autoclean")
|will enforce the correct ordering of loading and unloading modules in
|the SCSI subsystem.
|The individual upper and lower level drivers can be loaded in any order
|once the scsi core is present in the kernel (either compiled in or loaded
|as a module). The disk driver (sd_mod.o), cdrom driver (sr_mod.o),
|tape driver ** (st.o) and scsi generics driver (sg.o) represent the upper
|level drivers to support the various assorted devices which can be
|controlled. You can for example load the tape driver to use the tape drive,
|and then unload it once you have no further need for the driver (and release
|the associated memory).
|The lower level drivers are the ones that support the individual cards that
|are supported for the hardware platform that you are running under. Those
|individual cards are often called Host Bus Adapters (HBAs). For example the
|aic7xxx.o driver is used to control all recent SCSI controller cards from
|Adaptec. Almost all lower level drivers can be built either as modules or
|built into the kernel.
|** There is a variant of the st driver for controlling OnStream tape
| devices. Its module name is osst.o .