FPGA VAX update

[Tony Duell]

> ...and DIP-based TTL (and CMOS) is more "harvestable".   Before I toss out
> an old board with lots of DIPs on it, I think really hard about getting out
> the propane torch and removing the chips on it.  If the chips are SMT, it
> goes into the trash without a second thought.

Why? Although the manufacturers don't recomend it, I've had no problems 
removing and re-using SOICs, PLCCs, etc.

> 
> A friend, after retirement, has made a small career of working on Ruffatti
> pipe organs.  Instruments made in the 70's and 80's rely on a bunch of TTL
> and an MPU (I think it's 8086, but not sure) for the adjustable combination
> stop mechanism.  The outfit that designed it for Ruffatti and did the
> programming is long gone, not having left any documentation.  Fortunately,
> the logic's made of standard parts, the MPU has a well-documented
> instruction set and it's not hard to get a probe on pins to figure out
> what's going on--and one can purchase replacements.  I shudder to think of
> what would have happened if these things had been FPGAs.  An instrument
> like this can have a life of several hundred years and go more than 100
> years between renovation.

I am sure most of us here would much rather repair a board of TTL than 
something based around essentially undocumented parts. That's one reason 
I stick to classic computers, of course.

-tony