From: terryc on
Old rack mounted hardware, 8 disk drive slots and four female D9 sockets
on back.

So some how, data was through these D9 sockets.
I'm suspecting is was a dual ported hard disk array boxen.
Located in a support cabinet for a Concurrent Corporation Micro Five.
The other two units were SCSI1 plugs(D50).

This was just an unbadged black box and the only part of the label that
made sense was FDI.

Am I correct that it was an early firewire implementation to compete with
SCSI for hard disk access, or is it some proprietary system?

T.I.A.