Hanging a 2nd disk off a 3b2-310?
Peter Fales
pfales at ttrde.UUCP
Sun Jan 1 08:33:38 AEST 1989
In article <982 at vsi.COM>, friedl at vsi.COM (Stephen J. Friedl) writes:
> In article <7259 at chinet.chi.il.us>, randy at chinet.chi.il.us (Randy Suess) writes:
>
> > Yes, you can get any PC Klone type
> > hard disk [for the 3B2] that is 1024 cylinders - 8 heads or less...
>
> While there does indeed seem to be a limitation on 1024 cylinders,
> the 3B2 is happy to use up to sixteen heads (indeed, the stock CDC
> drives that ship from AT&T have nine heads). Congruent Technologies
> appears to have found a way to format a drive with > 1024 cylinders,
> but we've not been able to do so.
Sorry, this is pretty sketchy, but...
The earliest models of the 3B2/300 (possibly 310?) did only support disks
with eight heads or less. The following simple modification will
allow an early model 3B2/300 to use more than eight heads:
DISCLAIMER: I have done this myself and seen it work, however, NEITHER
I NOR AT&T CAN TAKE ANY RESPONSIBILITY FOR ANY DAMAGE TO YOUR SYSTEM
AS A RESULT OF ATTEMPTING THIS MODIFICATION.
My notes don't indicate what this chip
is, but it is right next to the Hard
Disk controller chip in this physical
location.
|
|
v
--------- -------------
| | | |
| 12|-+ | | <--- NEC Hard Disk Controller Chip
| | | | | 1) Isolate Pin 23
| | | | | 2) Add Wire from pin 27 to pin 12
| | | | |
| | | | |
--------- | | |
| | |
| | |
| | 27|------+
| | | |
| | 23|--X |
| | | |
| ------------- |
| |
+--------------------+
--
Peter Fales AT&T, Room 2F-217
200 Park Plaza
UUCP: ...att!ttrde!pfales Naperville, IL 60566
Domain: pfales at ttrde.att.com work: (312) 416-5357
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