SCSI

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SCSI

[′skəz·ē]
(computer science)

SCSI

SCSI

(Small Computer System Interface) Pronounced "scuzzy," SCSI is an earlier hardware interface for up to 15 peripherals connected to one expansion card, called a "SCSI host adapter." Introduced in 1986 by Shugart Associates (see SASI), this parallel architecture was replaced by its serial successor (see serial attached SCSI).

SCSI hard drives were used in mainframes, servers and storage arrays in the late 1980s and 1990s because they were very robust. Initially the only kind chosen for multi-drive RAID configurations, less-costly IDE drives were eventually used (see RAID, IDE and SATA).

SCSI Was a Mini-Network
The SCSI bus connects up to 15 devices in a daisy chain topology, and any two can communicate at one time: host-to-peripheral and peripheral-to-peripheral. For more details, see SCSI Architecture Model, SCSI signaling, SCSI connectors and SCSI switch.


A "Scuzzy" Daisy Chain
SCSI enabled multiple peripherals to take up only one expansion slot in the computer.







SCSI Ports
To enable the daisy chain, all SCSI devices had one "in" and one "out" port plus a dial to set the device number. These SCSI-1 sockets are on the back of a 1990s disk drive. See SCSI connectors.
References in periodicals archive ?
These environments combine financial account applications with Windows 2000-based hardware, and require the world-class support only available with Adaptec's Ultra2 SCSI RAID card.
A: Ultra2 SCSI, Ultral60 SCSI, or Ultra32O SCSI devices are backward compatible with the; single ended (SE) SCSI bus as long as the interface is the multimode LVD (also called LVD/MSE) interface.
A: Yes, the cables and terminators from Ultra2 SCSI can be used in Ultra160 SCSI.
Ultra2 SCSI drives in multimode, which are the previous generation but still widely used and sold in the market place, run 80MB/sec.
The Ultra2 SCSI drives do not have termination, so therefore you must have termination in the cable system.
Wide Ultra2 SCSI was defined by STA to use the LVD, 16-bit bus and 40megatransfers/sec data rate options of SPI-2.
The new product features hot swap, active/active, dual redundant RAID controllers with two 100MB/sec Fibre Channel host interfaces, eight Ultra2 SCSI LVD drive channels, and 1GB of cache memory.
Multi-channel Ultra2 SCSI systems can produce 80MB per channel.