Ultrix-32 supported SCSI disks and tapes and also proprietary Digital Storage Systems Interconnect and CI peripherals employing DEC's Mass Storage Control Protocol, although lacking the OpenVMS distributed lock manager it did not support concurrent access from multiple Ultrix systems.

* Serial SCSI Protocol ( SSP ) – supporting SAS disk drives

Initiator and target terms are applicable not only to traditional parallel SCSI, but also to Fibre Channel Protocol ( FCP ), iSCSI ( see iSCSI target ), HyperSCSI, ( in some sense ) SATA, InfiniBand, DSSI and many other storage networking protocols.

Many expansion boards were produced for Amiga computers to improve the performance and capability of the hardware, such as memory expansions, SCSI controllers, CPU boards, and graphics boards.

Other common categorization systems are based on the buses primary role, connecting devices internally or externally, PCI vs. SCSI for instance.

CD-R recording systems available in 1990 were similar to the washing machine-sized Meridian CD Publisher, based on the two-piece rack mount Yamaha PDS audio recorder costing $ 35, 000, not including the required external ECC circuitry for data encoding, SCSI hard drive subsystem, and MS-DOS control computer.

FireWire's high data bandwidth made it not only a suitable transmission medium for MIDI data, but also a replacement for the SCSI and IDE hard drive buses and ADAT Optical Interface audio transmission.

The icon / logo used for SCSI.

Small Computer System Interface ( SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices.

SCSI is most commonly used for hard disks and tape drives, but it can connect a wide range of other devices, including scanners and CD drives, although not all controllers can handle all devices.

The SCSI standard defines command sets for specific peripheral device types ; the presence of " unknown " as one of these types means that in theory it can be used as an interface to almost any device, but the standard is highly pragmatic and addressed toward commercial requirements.

* Serial attached SCSI, a computer bus technology for the transfer of data to and from storage devices ( e. g., hard disks )

* For high-end users, the LaserWriter II NTX also included a SCSI controller for storage of printer fonts on a hard drive dedicated for use by the printer.

* The LaserWriter IIf had a faster processor than the IINTX, a newer version of PostScript and also HP PCL, and included the SCSI interface for font storage on an external hard drive

Later, the Macintosh II was released which was much more suitable for desktop publishing because of its greater expandability, support for large color multi-monitor displays, and its SCSI storage interface which allowed fast, high-capacity hard drives to be attached to the system.

Therefore MS-DOS and, for example, OS / 2 could have different drive letters, as OS / 2 loads the SCSI driver earlier.

The 540 was unveiled in September 1990, and included higher speed SCSI and provision for connecting Genlock devices.

A number of Amiga peripherals were released by third-party developers for this connector including SRAM cards, CD-ROM controllers, SCSI controllers, network cards, sound samplers and video digitizers.

Although SCSI interfaces soon became available for PCs, they were comparatively expensive and tended to be limited by the speed of the PC's ISA peripheral bus ( although SCSI did become standard on the Apple Macintosh ).

Xenix 2. 3. 1 introduced support for i386, SCSI and TCP / IP.

Typically, this happens in a kernel-resident device driver that uses the existing network card ( NIC ) and network stack to emulate SCSI devices for a computer by speaking the iSCSI protocol.

In SCSI terminology, LUN stands for logical unit number.

Initiators treat iSCSI LUNs the same way as they would a raw SCSI or IDE hard drive ; for instance, rather than mounting remote directories as would be done in NFS or CIFS environments, iSCSI systems format and directly manage filesystems on iSCSI LUNs.

MeikOS had " diskless " and " fileserver " variants, the former running on the seat processor of an M²VCS domain, providing a command line user interface for a particular user ; the latter running on processors with attached SCSI hard disks, providing a remote file service ( called SFS, Surface File System ) to instances of diskless MeikOS.

In this sense all SCSI devices have a SCSI controller built into them, while host adapters ( unlike, for example, a hard disk or CD-ROM ) bear responsibility for transferring data between the SCSI bus and the computer's input / output bus.

The SCSI standards define commands, protocols, and electrical and optical interfaces.

By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances.

The protocol allows clients ( called initiators ) to send SCSI commands ( CDBs ) to SCSI storage devices ( targets ) on remote servers.

In essence, iSCSI simply allows two hosts to negotiate and then exchange SCSI commands using IP networks.

An initiator typically serves the same purpose to a computer as a SCSI bus adapter would, except that instead of physically cabling SCSI devices ( like hard drives and tape changers ), an iSCSI initiator sends SCSI commands over an IP network.

The host adapter usually assumes the role of SCSI initiator, in that it issues commands to other SCSI devices.

At least two models were produced, one with a manual lever that mechanically ejected the disc from the drive, and another with a small pinhole into which a paperclip could be inserted, in case the device rejected or ignored SCSI eject commands.

* SCSI CDB ( Command Descriptor Block ), used when issuing commands to SCSI devices

On the other hand, a SCSI target is the endpoint that does not initiate sessions, but instead waits for initiators ' commands and provides required input / output data transfers.

SCSI support added yet another CPU to interpret the SCSI commands, and track-following servos required analog components that often populated entire circuit boards of their own, thus driving up costs.

* High performance / high capacity data storage: early workstations tended to use proprietary disk interfaces until the emergence of the SCSI standard in the mid-1980s.

Two of these SCSI buses were used to store video data, and the third to store audio.

Two of these SCSI buses were used to store video data, and the third to store audio.

* SCSI Parallel Interface, in physical data transfer, a parallel electrical bus interface

ESDI could handle data rates of 10, 15, or 20 Mbit / s ( as opposed to ST-506's top speed of 7. 5 Mbit / s ), and many high-end SCSI drives of the era were actually high-end ESDI drives with SCSI bridges integrated on the drive.

By 1990, SCSI had matured enough to handle high data rates and multiple types of drives, and ATA was quickly overtaking ST-506 in the desktop market.

Improvements in modern hard drives such as RAM cache, faster platter rotation speed, command queuing ( SCSI TCQ / SATA NCQ ), and greater data density reduce the negative impact of fragmentation on system performance to some degree, though increases in commonly used data quantities offset those benefits.

A self contained unit holding 16 or more disks and connected by SCSI to a host computer, the library required specialized archival software to store indexes of data and select disks.

* Improved SCSI support with faster data throughput.

While the drive controller still addresses data blocks by their CHS address, this information is generally not used by the SCSI device driver, the OS, filesystem code, or any applications ( such as databases ) that access the " raw " disk.

SCSI technology advantages include allowing up to 15 devices on one bus, independent data transfers, hot-swapping, much higher MTBF.