Drums

From: allisonp_at_world.std.com <(allisonp_at_world.std.com)>
Date: Tue Apr 18 10:09:15 2000

> Hi,
> I think I heard somewhere that magnetic drums are somewhat like core memory,
> i.e. they retain their contents when shut off... I believe I read this in

Actually they are cylindrical disks with multiple heads in parallel so
that you can write a word or read one rather than serializing the bits.

Drums were used on PDP-8s, PDP-10s and likely others for small storage or
more commonly swapping out contents of memory. Think of this if you can
read or write a word in 1/1800(or 2400rpm) or a block of core eaqually as
fast swapping is viable to expensive and hard to get memory.


> getting, which are from Vermont Research and are approximately 256K or so..
> Also, does anyone know what other computer companies used drums from Vermont
> Research? They're for my Interdata 7/32, but I know at least Varian used
> Vermont Research drums... any others?

Oh, I'd love to get one. the last time I played with drum was 23+ years
ago and it was a small 14bit wide by 8192 word affair I used as a fast
disk till it died mechanically.

Allison
Received on Tue Apr 18 2000 - 10:09:15 BST