Info about a Mullard Core

Roger Holmes roger.holmes at
Wed Oct 31 19:37:59 CDT 2007


> From: "Gavin Melville" <gavin.melville at>
> Subject: Info about a Mullard Core

> Hi,
> I have had for many years a large core, and while I don't really  
> want to
> part with it, I also see what little pieces of core sell for on  
> ebay....
> I was told when given this about 15 years ago that it was from a
> Burroughs mainframe which was installed at the Cadburys head office in
> New Zealand and that they had paid GBP 20,000 for it in 1960.

20,000 for the core or for the mainframe?

How sure are you about it being Burroughs? Wouldn't they be using  
U.S. components rather than British?

I know Cadburys bought an ICT 1300 series machine around 1963/4, and  
its now in a museum in NZ. It was a 48 bit machine, but I think it  
had a much smaller store of 1200 or 2000 words and would have cost  
around 100,000 GBP. I have read there was an option to replace all  
the 'barn door' core stores with a single store of 4,000 words of 48  
bits, though I've never seen one, nor the logic diagrams. I have  
always wondered whether it used a full binary decode (using 16384  
words to provide 4000 words of usable memory) of the 14 bits rather  
than a BCD decode. The 1300s use lots of Mullard components.

Just a small piece of a jigsaw puzzle, maybe not even the right puzzle!

Roger Holmes.
Owner of the last working ICT 1301.

>   I have
> been unable to find out if this was correct however.   Does anyone on
> the list know anything about it ?
> pictures at
> There are 921600 cores in the array, which is made up of 48x48  
> cores, 4
> to a layer and 100 layers.
> _________________________________
> Regards,
> Gavin Melville
> Senior Engineer
> Acclipse Electronic Ltd

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