Magtape write rings [Was: Re: Full immersion emulation]

Chuck Guzis cclist at
Sun Mar 5 14:37:42 CST 2017

On 03/05/2017 12:18 PM, Jon Elson via cctalk wrote:
> Mention above about the vacuum capstans. Some really old drives had
> two continuously counterrotating capstans with slots in them. Valves
> applied either air pressure, to make the tape float over the capstan,
> or vacuum, to make the capstan grab the tape.

Doesn't feel "really old" to me, at least. :)

In the CDC drives, there was a voice-coil type valve for switching the
vacuum around.  I understood that the 65x units had a "cost reduced"
version of the valve, from the 60x units.   All in all, I much preferred
the big orange 60x drives to the gray metal and blue glass of the 65x
one--the 60x drives just felt more sturdy.


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