[personal] UK Computer Museum on TV

Mike Hatch mike at brickfieldspark.org
Thu Jun 5 08:15:45 CDT 2008

TM4's were on the SDS9300, six of them, as I recall they were 10 track but 
something also says 9 track, after all it was 35 years ago !..
There were also TM4's fitted to an ICL (I think a 1901) machine up in London 
but I only visited for service once (dirty contacts on the tape arm 
There were also TM2 drives on a LEO3 #26 at Charles House in London 
maintained by ICL for running gas bills. I gather quite a number of the Leo 
machines used TM drives.


----- Original Message ----- 
From: "Roger Holmes" <roger.holmes at microspot.co.uk>
To: <cctalk at classiccmp.org>
Sent: Thursday, June 05, 2008 9:50 AM
Subject: Re: [personal] UK Computer Museum on TV

>> From: "Mike Hatch" <mike at brickfieldspark.org>
>> Have past experience with Elliott 803b, Digital PDP7 & 11/20,  Scientific
>> Data Systems SDS9300, ASR/KSR 33 & 35, Ampex TM4 tape drives.
> May I ask what machine the Ampex TM4 tape drives were connected to? I 
> have them on my ICT 1301s, and I have a slightly different deck  marked 
> TM4 Leo but if you know of any other machines which used them  it would be 
> interesting. Do you know if they were always ten track  read/write heads 
> or were they different configurations? I guess the  formats were different 
> across different machines, it seems unlikely  anyone else would have 
> chosen to use 4 data bits and 6 CRC bits, and  certainly not in multiples 
> of 12 digits with the digits from each  half of the word interspersed 
> ending at a word of hex FFFFFFFFFFFF.
> Roger

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