26 Jul
2014
26 Jul
'14
3:57 p.m.
On 7/26/2014 1:39 PM, Tony Duell wrote:
[VAX 11/730 is almsot all PALs]
The source equations for the PLDs and the truth tables for the ROM are
included as schematic pages for the 11/780 and the 11/730.
I don't know how ECO's (if any) were managed - and not sure if the
equations on the schematic pages were kept up-to-date. I have a fuzzy
memory that the PLDs were socketed.
Rob.
Interesting point. A friend of mine had both a
725 and a 730 back
around 1990ish (sadly, they were long gone by the time I got interested
in having a VAX to call my own). One had a bad PAL, but he could run
either machine by swapping in the good PAL from the other machine. :)
I cna't rememebr if the PAL equations are in any of tyhe puiblished
manuals, but I am darn sure that DEC relied only on waht H&H call
'security through sodler'.They did not blwo the security fuse of the PALs
in the 11/730. If you were prepared to desolder them and stick them in a
pgoramemr uou coudl read out the fuse map and recreat e the logic
equaitons.
-tony