Path: utzoo!attcan!uunet!husc6!bu-cs!buengc!bph
From: bph@buengc.BU.EDU (Blair P. Houghton)
Newsgroups: comp.lsi
Subject: Re: memories
Message-ID: <391@buengc.BU.EDU>
Date: 9 Jul 88 20:44:32 GMT
References: 
Reply-To: bph@buengc.bu.edu (Blair P. Houghton)
Followup-To: comp.lsi
Organization: Boston Univ. Col. of Eng.
Lines: 29

In article  grzybows@math.rutgers.edu (grzybowski) writes:
>
>What about really high capacity memories?

Look up "Bloch Line Memory" in current and ancient literature.

I heard about it only a few months ago, and the guy who gave the seminar
said something about 300Meg per chip; 'course, your mileage may vary :-)

It's a variant on bubble-memories (still the highest-density working
technology) in which, rather than the existence of a domain wall being
the "bit", one puts half-twists in the wall and calls that a "bit".
The bubbles get stretched out like rubber bands, and twisted like
screwy macaroni.

Come to think of it, a thick rubber band might be a good visual aid
for teaching that these things are indeed stable states of the
domain wall...not physically parallel, maybe, but visually
mnemonic.

Actually, that number worries me; check it out; my brain cells have been
ASL for a while, and I don't have my notes from the lecture.  Still,
with the Mil running all over themselves, and the Fed running down the
Japanese, trying to get 1MB DRAM up to speed, a little slow, para-serial
Library-storage device may be a kick in the pants...

					--Blair

(p.s. old 6502 programmers know what ASL is.)