SCSI Information
Background
It all started back in 1979 when the diskdrive manufacturer come with the
bright idea to make a new transfer protocol. The protocol was named Shugart
Associates Systems Interface, SASI. This protocol wasn't an ANSI standard,
so NCR join Shugart and the ANSI committee X3T9.2 was formed. The new name
for the protocol was, Small Computer Systems Interface, SCSI.
Common Command Set, CCS, was added in 1985. ANSI finished the SCSI standard
in 1986. SCSI-II devices was released in 1988 and was an official standard
in 1994. SCSI-III is currently not yet official.
Usage
SCSI is used to connect peripherals to an computer. It allows you to connect
harddisks, tape devices, CD-ROMs, CD-R units, DVD, scanners, printers and
many other devices. SCSI is in opposite to IDE/ATA very flexible. Today
SCSI is most often used servers and other computers which require very
good performance. IDE/ATA is more popular due to the fact that IDE/ATA
devices tend to be cheaper.
Definitions
SCSI
Short for Small Computer Systems Interface. The original SCSI protocol.
ANSI standard X3.131-1996. Busspeed 5 MHz. Datawidth 8 bits.
SCSI-II
SCSI-II adds support for CD-ROM's, scanners and tapedrives.
Fast SCSI-II
Uses the busspeed of 10MHz instead of the original 5MHz.
Wide SCSI-II
Uses 16 bits instead of the original 8 bits.
Ultra SCSI-III
Uses the busspeed of 20MHz.