How scarce (valuable) is core for the PDP-8?

From: CLASSICCMP_at_trailing-edge.com <(CLASSICCMP_at_trailing-edge.com)>
Date: Thu Apr 22 07:30:15 1999

Mike wrote:
>> Perhaps a
>> smaller array, but with LARGE cores where the magnetic state could have
>> some visual indicators.

>How would that work? Would you have an LED for each bit or something?

Get a little bit away from magnetic storage, and you can use neon
lamps as storage elements which are self-illuminating :-).

Neon lamps - when powered by DC - have a nice memory property: They
take about 90VDC to light up, but after they light up they'll stay on
until the voltage drops below 60VDC or so. Only problems are:

1. The thresholds can vary greatly from unit to unit.

2. The thresholds will vary depending on ambient light, as well.

Property 2 above can be used to build oscillators out of pairs
of neons, as a matter of fact...

Tim.
Received on Thu Apr 22 1999 - 07:30:15 BST