From: "r. 'bear' stricklin" <red(a)bears.org> The -FA and -GA models have a SCSI controller board (TZK50) with the drive, in the box which is about 12.5 inch (32 cm) wide. Assuming that the "-D" is the one which is about two-thirds as wide, it is just the raw drive with its ribbon cable going to a (largely idle) 50-pin D connector (as I recall). It connects to a suitable controler, such as the Q-bus TQK50 or the UNIBUS TUK50. I believe that it was most commonly used with big-old UNIBUS machines like the VAX-11/7xx, which had no convenient place for an internally mounted TK50 drive, whereas most Q-bus systems did. Nowadays, the most common use for one is probably as a safe place to keep a spare drive, in case the drive in one's -FA or -GA fails. ------------------------------------------------------------------------ Steven M. Schweda (+1) 651-645-9249 (voice, home) 1630 Marshall Avenue #8 (+1) 612-754-2636 (voice, work) Saint Paul MN 55104-6225 (+1) 612-754-6302 (facsimile, work) sms(a)antinode.org sms(a)provis.com (work)