ACS Altos 3068

Phill Harvey-Smith afra at
Sat Jan 3 04:25:17 CST 2009

jeff.kaneko at wrote:
> WHat's the approximate vintage of this machine?
> I'm asking because many early designs (pre 1988,

About the 1986-88 time frame.

> or so) used non-standard 'SCSI like' interfaces
> to talk to ST-506 or ESDI drives.

Well the machine's drives are ST-506 MFM drives controled by a WD2010, 
though oddly with 16 sec/trk rather than the more normal 17, that most 
PC MFM interfaces used. It also has a QIC-02 60M tape drive, and a 1.2M 

> The Adaptec ACB-4000 was such a device, for example.
> It was marketed as a SCSI bridge, but in reality it
> was closer to SASI.  OMTI made similar boards,
> and you could almost never sub one for the other
> because of different implementations of SCSI.

Yeah I have an external disk box for the RM-186 that as I believe a 
Xybec SASI to ST-506 board in it, I tried getting that to talk to a 
moden controler and it would not, though I have recently discovered that 
Adaptec SCSI cards don't seem to like really old drive like this which 
may have been part of the problem in that case.

> I saying all of this because if this is true, then
> attaching a modern SCSI drive will get you nowhere.

Indeed, though it is labeled as SCSI on the back of the machine, and I 
remeber there being a similar looking SCSI chip in there to the ones in 
the Sun-3 systems I used to own.



Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.

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