The Digital Storage Systems Interconnect (DSSI) is a computer bus developed by Digital Equipment Corporation for connecting storage devices and clustering VAX systems. It was designed as a smaller and lower-cost replacement for the earlier DEC Computer Interconnect that would be more suitable for use in office environments. DSSI was superseded by Parallel SCSI.[1]
It was introduced in 1988 and has a bandwidth of 32 Mbit/s (4 MB/sec) and was typically limited to a length of 25 metres (82 ft). DSSI support was later extended to MIPS-based DECsystems and DEC Alpha-based AlphaServer systems.
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.