Difference between revisions of "Digital Storage Systems Interconnect"
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| − | The '''Digital Storage Systems Interconnect''' (usually given as '''DSSI''') is a [[mass storage]] [[bus]] from [[Digital Equipment Corporation|DEC]]. It can also be used to create loosely- | + | The '''Digital Storage Systems Interconnect''' (usually given as '''DSSI''') is a [[mass storage]] [[bus]] from [[Digital Equipment Corporation|DEC]]. It can also be used to create loosely-coupled [[multi-processor]]s by sharing a number of [[disk drive]]s between two systems. Such shared drives are termed 'Integrated Storage Elements' (ISEs). |
[[File:The SCA Model.png|thumb|right|350px|Systems Communication Architecture]] | [[File:The SCA Model.png|thumb|right|350px|Systems Communication Architecture]] | ||
Revision as of 14:34, 25 March 2023
The Digital Storage Systems Interconnect (usually given as DSSI) is a mass storage bus from DEC. It can also be used to create loosely-coupled multi-processors by sharing a number of disk drives between two systems. Such shared drives are termed 'Integrated Storage Elements' (ISEs).
Description from the 'Digital's Storage System Interconnect' protocol specification document:
"The DSSI, supporting the needs of low-end and mid-range systems, is one in a family of high-performance computer-to-computer interconnects (CI's) that combine a common host interface and port layer with an implementation-specific datalink and physical interconnect.
CI-class interconnects provide the transmission services required by Digital's Systems Communication Architecture (SCA) - a four-tiered set of protocols and interfaces as shown [to the right]."
The QBUS DSSI peripheral was the KFQSA. Some VAX CPU's had built-in DSSI peripherals, called 'Embedded DSSI Adapters' (EDAs); one such was the KA640 CPU of the MicroVAX 3300/3400. The VAX 4000 series also supported the DSSI.
External Links
- DSSI - DSSI and related documents at Bitsavers
- Digital's Storage System Interconnect - protocol specification document
- MicroVAX Dual-Host Systems (EK-338AC-DH-003) - contains a clear description of how a DSSI can be used to create a loosely-couple multi-processor
