ALTAIR stuff (was Re: E-Over Pay strikes again! originalAltairdisk sells for... )

From: Richard Erlacher <edick_at_idcomm.com>
Date: Sun Feb 14 08:54:51 1999

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_at_world.std.com>
> To: Discussion re-collecting of classic computers
<classiccmp_at_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
Received on Sun Feb 14 1999 - 08:54:51 GMT