Front panel switches - what did they do?

Jon Elson elson at
Thu May 26 11:35:57 CDT 2016

On 05/26/2016 05:02 AM, Noel Chiappa wrote:
> In addition to reading/writing memory locations, and basic machine control
> (boot, start, stop, continue, single-step, etc), some machines had additional
> functionality, but what it was (if any) varied widely from machine to machine.
Most IBM 360's had "ripple tests".  You could select local 
store (register set), main store or control store.
Then, when you pressed start, you could read every location 
of control store and optionally halt if a parity error 
occurred.  For local or main store, it would write 
alternately all ones and all zeros and read back and check 
This was a quick check that major components of the machine 
were in operating order.  (I don't recall if you needed the 
CE key to do these tests.)


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