Digital Storage Systems Interconnect

The Digital Storage Systems Interconnect (DSSI) is a bus developed by Digital Equipment Corporation for connecting storage devices and clustering VAX systems and support was extended to MIPS based DECsystem and later to Alpha processor based AlphaServer systems.

It was introduced in 1988 and has a bandwidth of 32 Mbit/s and was typically limited to a length of 25 meters.

DSSI peripherals could be distinguished from narrow SCSI devices by their characteristic five conductor power connector featuring an extra lead intended for Battery/UPS connection to power critical components in the event of a power failure.

The major characteristics of the DSSI bus are:

Other companies, such as CMD and Symbios Logic made DSSI compatible chipsets or peripherals, for example, CMD manufactured various models of the CDI-4000 which would allow SCSI peripherals to be used on a DSSI bus.

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