Documentation/scsi/scsi.txt - linux - Git at Google

 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://web.archive.org/web/*/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 .
	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://web.archive.org/web/*/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 .