SCSI

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SCSI

[′skəz·ē]
(computer science)

SCSI

SCSI

(Small Computer System Interface) Pronounced "scuzzy," SCSI is a hardware interface for up to 15 peripherals connected to one PCI or PCI Express card ("SCSI host adapter") on the motherboard. Introduced in 1986 by Shugart Associates (see SASI), this original parallel architecture was largely replaced by a serial version (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, and they were initially the only ones used in RAID configurations (see RAID). Eventually, less-costly IDE drives became highly reliable (see IDE and SATA).

SCSI Is a Mini-LAN
The SCSI bus is like a mini-LAN connecting 15 devices; actually 16 but the host counts as one. 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 connect to one host adapter and take up only one slot in the computer. Devices included two ports to form a daisy chain.
References in periodicals archive ?
Differential SCSI along with its single ended alternative had reached the limits of what would be physically reliable in transfer rates, even though the flexibility of the SCSI protocol allowed for implementing much faster communications.
Low Voltage Differential SCSI (LVD) is the answer to both problems associated with the physical SCSI interface.
Example: There is a requirement to upgrade the speed and capacity of a drive package in a differential SCSI based system, but the fastest and highest capacity hard disk drives have only come out in LVD SCSI.
The LVD/Wide Ultra2 offers longer system cable lengths, higher noise immunity and creates less heat than previous high voltage differential SCSI interfaces.
Support for new low voltage differential SCSI (LVDS) enables remote drive placement -- The HP SureStore DAT40 drive can be placed wherever convenient, not just directly adjacent to the server as required by previous SCSI specifications.
Supporting the most advanced storage options available, such as hot-swap drives and RAID-capability, the Magnia 3010 and 5010 also provide compatibility with industry-standard technologies including low voltage differential SCSI (LVDS).
The IQstor(tm) line will support Single or Dual Loop Fibre Channel, Ultra Wide Differential SCSI, LVD Ultra2 SCSI and Ethernet, as well as have SAN compatibility.
Available with Single or Dual Loop Fibre Channel as well as Ultra Wide Differential SCSI, LVD Ultra2 SCSI or Ethernet, the R1500 comes equipped with a JAVA-based GUI for easy network management.

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