MPI-52 as replacement for SA400?

[Don Maslin]

On Thu, 1 Jan 1998, Bill Richman wrote:

> Is the SA-400 the standard Northstar floppy drive?  I've been running
> a Northstar floppy controller in my IMSAI, using just a couple of
> plain old IBM-XT floppy drives.  I was clued in by someone else on
> this list that they would work, and they seem to be fine; even
> handling the original hard-sectored diskettes!  I was under the
> impression that the sectoring was at least in part determined by the
> drive, but have been told (and have seen for myself) that this is not
> so; it's determined by the controller.  Hope this helps!

You are correct, Bill.  I have substituted a half-high 720k 5.25" drive 
for the full high 100tpi drive on a 16-hard-sector Vector Graphics quite 
successfully.

> On Tue, 30 Dec 1997 19:37:37 -0600 (CST), you wrote:
> 
> >
> >I've got a Northstar Horizon that I'm starting to restore.  The Northstar
> >manual indicates that the Northstar disk controller wants to talk to one
> >or two SA400s, which sounds about right considering the time period.
> >
> >Problem is the only SA400s, or similar, that I have are in my SWTPC 6800
> >and I don't want to pull them.  I know that the SWTPC will accept an 
> >MPI-51 as a replacement for an SA400 (but not an SA400 on a controller 
> >that expects to see MPI-51s since they have a slightly higher step rate).
> >
> >Could I use an MPI-52, and under what conditions, as a replacement for
> >the SA400s that the Northstar wants to see?  If so, why?  If not, why not?
> >
> >Thanks...
> >
> >Anthony Clifton - Wirehead
> 
> 
>                             -Bill Richman
>                              bill_r at inetnebr.com
>                              http://incolor.inetnebr.com/bill_r
>                             
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>
						 - don
    donm at cts.com
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    Don Maslin - Keeper of the Dina-SIG CP/M System Disk Archives
         Chairman, Dina-SIG of the San Diego Computer Society
       Clinging tenaciously to the trailing edge of technology.
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