Any own an 11/725...?

[Don North]

William Donzelli wrote:

>>All I see there is a VAX-11/780 picture, not a VAX-11/725.  I'm not 
>>sure, but I don't believe I've ever seen anything other than a 
>>drawing of the VAX-11/725.
>>    
>>
>I have only seen a few, and used one at school years ago. Painfully slow,
>I remember, even compared to our overworked /780 and 3600.
>
The VAX-11/725 was a repackaged version of the VAX-11/730 (smaller box 
for OEM usage). 11/725 and 11/730 were the same board set, so 
performance was the same, ~1/3 that of an 11/780. Ok for a single user, 
not too spiffy otherwise otherwise.

The machine was implemented with lots of first generation 20pin PALs 
(which just came to market in the late 70s), and 2901 bit slices for the 
main datapath. The '730 was heavily microcoded in a narrow word (24~32b 
wide, 16K deep IIRC) style compared to the existing 11/780 (96b wide 
microword, 1K-2K deep).