Bubble memory devices - test-drb@ccmp.vtda.org

20 Feb 2008

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Subject: Re: Bubble memory devices
   From: "Chuck Guzis" <cclist at sydex.com>
   Date: Tue, 19 Feb 2008 13:44:53 -0800
     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>

A bit of curiosity on my part...

If one wanted to replace a whole bubble memory card (i.e. complete 
with support chips and decoders), would MRAM or FRAM be considered a 
suitable substitute?  It'd be one heckuva lot faster and drink less 
power. 
Yes and no.  yes you can use ram (or flash) as "disk" but the bubble
system was addressed and generally run like a FDC with a command-status
register and a data register.  To have ram look like that you's need 
some controller and/or hardware.  IT would also impact software that 
was designed to talk to it.

Bubble was not RAM is was block accessable storage.

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 In the same vein, how about MRAM as a core memory
substitute? 
Yes, it's been done.  I had an 8E with a ram card, It stayed with
the machine when I passed to to someone else.  Also PDP-11s (early) 
could ahve ram or core and I ahve a 16k core stack for a Qbus LSI-11.

Allison

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 Cheers,
Chuck