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

From: allisonp_at_world.std.com <(allisonp_at_world.std.com)>
Date: Tue Apr 20 09:13:36 1999

> Can you translate that to a size? I can imagine the size of a #4 nut
> (I have several). I can't clearly picture how big the O.D. of a #2 would be.
>
Roughly .1375 across the hex faces.

> > ...A good material for this is hypersil commonly used for transformers.
>
> Used for the windings or the core laminations?

Hypersil is a silicon steel alloy and is used for laminations. Copper, is
the wire.

> On the topic of core size vs switching speed, I'd always assumed the drive
> to minaturize core was driven by the economics of memory density. I never
> considered memory speed.

That is only part of the picture. Core size affects switching speed and
current needed to switch. Compounding this is more wire means
resistance, heat and inductance all influencing how fast you can switch.
Core is where magnetics, analog and digital intersect.

Allison
Received on Tue Apr 20 1999 - 09:13:36 BST