Emulators of Classic Computers

From: Tom Jennings <tomj_at_wps.com>
Date: Thu Jan 22 16:55:14 2004

On Tue, 2004-01-20 at 15:50, William Donzelli wrote:

> Have you obtained all of the tubes you need? I noticed on your websight
> you mention using "Red Series" tubes. As you probably figured out, those
> (RCA Red Line or Bendix Red Bank) are pretty expensive.

THe electronic design was abandoned for now. Basically I was to
(will...?) build a 4 x 4 switched cap memory which will be a nice
reality check on flops, tubes, etc.

Also, I chased down and read the exhaustive life-testing book the US Mil
sponsored (forget the title) in the early 60's re: tube reliability.
Though it applied specifically to subminis, it quantified what the
computing people knew: derate, derate, derate. They got easily 16,000
hours from selected devices. The suspected more was easily possible, but
that was the extend of their testing. It was interesting that some
devices worked better/longer at slightly elevated Vff.

Also, if you look at general tube electronic environments throughout the
50's, excepting the smartest stuff (Tek scopes etc) the power supplies
are total crap. Unregulated and unsequenced. That did a lot of harm. It
was fine for radios but not for "high speed" switching where margins
started to matter.
Received on Thu Jan 22 2004 - 16:55:14 GMT