SCSI (pronounced SKUH-zee and sometimes colloquially
known as "scuzzy"), the Small Computer System Interface, is
a set of evolving American National Standards Institute (ANSI) standard
electronic interfaces that allow personal computers to communicate with
peripheral hardware such as disk drives, tape drives, CD-ROM drives, printers,
and scanners faster and more flexibly than previous interfaces. Developed
at Apple Computer and still used in the Macintosh, the present set of
SCSIs are parallel interfaces. SCSI ports are built into most personal
computers today and supported by all major operating systems.
In addition to faster data rates, SCSI is more flexible than earlier
parallel data transfer interfaces. The latest SCSI standard, Ultra-2 SCSI
for a 16-bit bus can transfer data at up to 80 megabytes per second (Mbps).
SCSI allows up to 7 or 15 devices (depending on the bus width) to be connected
to a single SCSI port in daisy-chain fashion. This allows one circuit
board or card to accommodate all the peripherals, rather than having a
separate card for each device, making it an ideal interface for use with
portable and notebook computers. A single host adapter, in the form of
a PC Card, can serve as a SCSI interface for a "laptop," freeing
up the parallel and serial ports for use with an external modem and printer
while allowing other devices to be used in addition.
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