ACB-4000 and Micropolis 1325

In old Sun 3/160 and in the shoebox you can often find a QIC-24 tape drive and one or two MFM hard drives. These MFM disks were either Fujitsu M2243AS or Micropolis 1325 with 70 MB. Of course their size was 5.25" and full height.

Here come pictures of a Micropolis 1325:

picture (147 kByte): Micropolis top view picture (150 kByte): Micropolis bottom view

On the top you can see the defect list. This is a (dot matrix) printout. These days hard disks didn't store their defect lists on the media or in a ROM on the controller. You had to type it in before you could low level format the disk! This was necessary if you ran the disk on another controller (in a PC for example) before.

The MFM disks were connected to the SCSI bus via an adapter. Sun used the MFM-SCSI bridge ACB-4000 from Adaptec, which could serve two disks.

picture (213 kByte): ACB-4000

One curiosity of the ACB-4000 is worth mentioning: If two disks are attached, they move their heads syncroneously, not independent.

Copyright 1999-2007 Peter Koch