[GreenKeys] paper tape variants

[Randy and Sherry Guttery]

Chris Elmquist wrote:
> Very impressive and thanks for the link on that!
Glad you found it of interest.
> Amazing to see what appears to be the rough equivalent of a 5.25" hard
> drive in the Verdan.  The rest of us didn't see such a thing until,
> what, 25 yrs later?
>   
As noted - while it is indeed a rotary disk device - it's primary use 
was as the "circulating registers" of the arithmetic unit(s), rather 
than as permanent storage; although there was some "storage"... The 
power supplies were "stout" enough that if the unit sensed a power loss 
- the contents of the circulating registers were "frozen" in their 
tracks; and the contents of the flip-flops were stored in some special 
register areas.  When power was restored - everything would re-load - 
and then the machine would pick back up at the precise point it left off 
- and continue right along.  The MARDAN's disk was double-sided,  but 
still used primarily as working registers - and integrators - just more 
of them.
> Pretty cool.
>
>   

Yeah - for us youngsters right out of school - where they were still 
teaching tubes and  B&W TV as the most advanced electronics - yeah 
pretty cool!
best regards...

-- 
randy guttery 

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