ALTAIR stuff (was Re: E-Over Pay strikes again! original Altairdisk sells for... ) - test-drb@ccmp.vtda.org

13 Feb 1999

There's good reason for that, namely, that the 8" FDD, for which a standard
then existed, used a 50-pin cable, while there seemed to be several
variations early in the mini-floppy game.  The 37-pin cable you see on the
IBM-PC FDC is certainly not the same, nor was it ever very important.  

The cable between the FDC in an S-100 box and the drives, normally 8"
drives, normally packaged externally to the cardcage, was most often a
50-pin flat cable, though a 37 could have handled the task if you didn't
mind that there was not a ground for every signal.  The early FDD's were
typically hard sectored and used more signals than were required by the
later models.

The insides of the ALTAIR FDD box were not simple and clean like their
successors.

Dick

----------
...
  From: Don Maslin &lt;donm(a)cts.com&gt;
 To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
...
  Subject: Re: ALTAIR stuff (was Re: E-Over Pay strikes
again! original Altairdisk sells for... )
...
  Date: Saturday, February 13, 1999 12:49 PM

 Well, I would not venture to suggest just where it originated, but the
 37-pin D-sub connector has pretty much (there have been exceptions) been
 the standard for connecting external floppy drives of all sizes.  Almost
 all PC (ISA) FDCs that support external drives use it, and the Xerox 820
 (CP/M) series used it.  Most S-100 crates did not, as they typically ran
 the ribbon cable direct from the card to the drive.

 						 - don

 On Sat, 13 Feb 1999, Richard Erlacher wrote:

 > What I find odd about the MITS FDD is that they used a 37-pin "D"
connector
...
  > and cable as opposed to the 50-pin more commonly
seen on the 8" types.  I
...
  > found one among a set of enclosures I bought
about 20 years ago.  While
 > this is already promised out (once I find the top of the box), I do know
...
  > that there's an ALTAIR hard disk controller
box, apparently with a drive
...
  > inside, judging from the weight, at Gateway
Electronics in Denver, (303)
...
  > 458-5444, if anyone's interested.  It's
the same size as the ALTAIR FDD
 > box.
 > 
 > Dick
 > 
 > ----------
 > > From: Allison J Parent &lt;allisonp(a)world.std.com&gt;
 > > To: Discussion re-collecting of classic computers
 > &lt;classiccmp(a)u.washington.edu&gt;
 > > Subject: RE: E-Over Pay strikes again! original Altair disk sells for 
...
  > > Date: Friday, February 12, 1999 6:34 PM
 > > 
 > > 
 > > <True enough I'm sure.  MITS also produced a "mini"-floppy
controller
 > that
 > > <was also a two board TTL set.  The first board (computer interface)
was
...
  > th
 > > <same board as in the 8" set (except for different RC values), the
second
...
  > > 
 > > Well heres where I stand on it.  Never seen one, I was there, and never 
...
  > > seen an advert for one, I have back issues. 
Was it possible, sure.  The
...
   8" 
  design with some tweeks would certainly do
minifloppy.

 Allison 