An historical nit about FDDs

Jon Elson elson at
Fri Jul 13 23:11:55 CDT 2018

On 07/13/2018 01:04 PM, Tom Gardner via cctalk wrote:
> Jon:
> The 23FD used on most S/370 mainframes had a two solenoid and swash plate actuator, pulse the in  solenoid to go in and the out solenoid to go out.
> IBM SJ in those days was very cost conscious and preferred mechanical parts over electronic, hence this mechanism instead of the stepper motor implement by most (all?) other FDD manufacturers.
Right, this is what I heard and saw on a 370/168.  I THINK 
the 370/145 used the same drive.


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