wouldn't you do well to ask Dave? He's
probably got images of the
 s/w. 
 I did, and he wrote Superbrain's disk drives wrote data in some
 "inverted" fashion and it is complicated to write them using usual PC
 floppy drives, so that's why he didn't put images on website. 
 
  The data is inverted, but the address marks are normal.  By and
 large 10-sector formats.  I am aware of about 5 different Superbrain
 formats:  The exception is the 30x128 byte sector MFM format, which
 can be written with a controller that uses the National DP8473
 controller (common on ISA SCSI+Floppy controllers, particularly
 Future Domain and DTC).
 Here is what I have samples of:  (sector size/sectors per
 track/sides/cylinders):
 1. 512*10*1*35 MFM
 2. 512*10*1*40 MFM
 3. 512*10*2*35 MFM1
 4. 512*10*2*80  MFM
 5. 128*30*1*40 MFM
 The Wren Executive shares the second format with the Superbrain. 
 
BTW, is it possible to replace Superbrain's drives to something
different? Maybe it would be easier to boot it then and copy image from
replaced drive to original? (My Superbrain has two drives).