14 Feb
1999
14 Feb
'99
12:54 a.m.
Well . . . I'd make the observation that while the ALTAIR was certainly
built in the mid 1970's, several of the other machines to which you refer
were not, not were the "mini-floppy" drives which later became common.
In the mid-'70's, both ribbon cable and IDC connectors were quite costly by
comparison with up-to-then common labor intensive hand wiring. As the
economies of scale took effect, ribbon and the associated connector
mechanisms became both cheaper and more reliable, so that, by the time the
mini-floppies were accepted, the associated ribbon cable hardware was
firmly intrenched in the market. The plastic (T&B Ansley in this case)
ribbon cable connectors were not the best available. The old 8" drives had
enough signals which were used early in the game that the 50-conductor
cable became the standard as opposed to the 34-pin, which could easily
handle the operation of a drive once the later-accepted conventions were in
place.
At the time of the ALTAIR, these conventions were not yet in place.
Dick
----------
From: Allison J Parent <allisonp(a)world.std.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Subject: Re: ALTAIR stuff (was Re: E-Over Pay strikes
again!
originalAltairdisk sells for... )
Date: Saturday, February 13, 1999 10:16 PM
<I'm not sure you're right about the assertion that 37 is enough. Maybe,
<but the old drives used more signals than the later ones.
At this point I'd say this. I was there and used then first products.
I even hand made cables. The oldest 5.25 floppies didn't used the full
34 pins and the 8" drives didn't either. Many of the pins in the 8" case
were used in exchange for others but the odd pins in
both 8" and 5" were
all ground and you didn't have to use all of them. the latter being the
common case.
the best example of this is the DEC VT180 CP/M machine D37 on the back of
the box to a DB25 on the drives. The drives were
SA400L or tandon
TM-100.
<The shielded cables using the DC37 connectors certainly were more
durable
<than the IDC50 types one often sees, but the cable
hardware in the
ALTAIR
<box certainly was the cheapest available. I doubt
it was any more solid
<than the IDC types.
Believe it. The cable was hand wired and IDC in the mid '70s was really
new, expensive and not quite ready for pimetime. IDC was more an early
80s item brought to the party.
I have the small but significant advantage in that I was old enough to
have
been in the engineering business over 6 years before
the altair. So I
got
to "be there and see there" alot. That and
I bought an early Altair
and helped a few business and hardy hackers build and get theirs going.
Allison