[Simh] VUPs?

[John H. Reinhardt]

Norman Lastovica wrote:
>
> 	The 8650 had a significantly faster clock speed than the 8600
> (55ns vs 80ns cycle time).  Perhaps the microcode did get some tweaks
> as well.  I believe that at the time the 8600 was supposed to be a flag
> ship and I suspect probably didn't have many feet burdened by ball and
> chain.
> 	The story that I am aware of had to do with the 8500.  It was
> released at about the same time as the 8700/8800 but needed to be slower 
> presumably for marketing reasons.  Supposedly it shared the same hardware 
> and clock rate.  I understand that at some point in time there was a new 
> version of the microcode code released to fix or enhance something or
> another.
> Users of the 8500 noticed a performance increase with this new code
> that lacked the foot dragging of the prior code.  So it was then given
> to all of the 8500 customers as an "upgrade".  I do not remember the
> rest of the story though as related to the 8500, 8530 and 8550 (which
> from my memory were more or less the exact same computer).  Perhaps
> they were basically the same machines with different amounts of streamlined 
> microcode?   My memory has been lost to the sands of time.
>
>
>   

Ooooh. Maybe it was the 8500/8550 I was thinking of.  Similar model 
numbers and fading memory cells...  *sigh*