Who collects (reads the mailing list...?) vintage computers

From: ajp166 <ajp166_at_bellatlantic.net>
Date: Mon Oct 16 21:27:04 2000

From: Richard Erlacher <richard_at_idcomm.com>


>Was that uPD 372 the version that handled hard-sectored diskettes as
well?


It could.

>I remember they had a uPD 371 as well, but I'm not remembering whether
it
>was a tape controller or a hard-sectored disk interface controller. I
seem
>to remember something of that sort being available in the mid-late
'70's.


All the way up to 1980. I have some 371s too. makes a fair tape
controller.
Though I found using a 765 or 1793 far easier to use as the old 37x parts
were three voltage nmos and two phase clocks. They were ok with
systems that had 8080s.

>I remember Robert Suding once telling me that the reason they couldn't
do
>any better with their FDC's was because the 74S124 (VCO) was too
expensive.
>Now, I used it from time to time and don't rmember ever paying more than
$2
>for one. Of course, you never know how long before then the DG people
were
>trying to buy the things.


the 74124 was fast enough and pretty cheap. PLLs using it were a pita.
If you used it there was a lot of other TTL around it so it was not the
cheapest
way to go and often the flakeyest. A good design with oneshots worked
well enough. Later one when people figured out how to do a digital
oneshot
or digital PLL then it got real cheap.

Allison
Received on Mon Oct 16 2000 - 21:27:04 BST