FPGA VAX update

[Chuck Guzis]

On 11/3/2005 at 11:40 AM Paul Koning wrote:

>The rumor has it that the NSA asked for it.  Certainly that makes
>sense.

...and perhaps accounts for why the instruction that was so fast on the
6600 also was one of the slowest on the 6400.  Clearly, it was implemented
with a view toward the high-end customers.  I'd pretty much only seen it
used as part of some fancy hashes and for counting bits in allocation
tables. 

>It was also used extensively in the PLATO system.  If you want to do
>fuzzy matches (i.e., accept misspellings for words), a nice way to do
>that is to encode the words in a clever way, XOR the intended word
>with the supplied one, bitcount the difference, and accept it if the
>number of bits that differ is less than N.

Of course, on the Star-100, we already had an instruction to do fuzzy
matches.

>Sure was.  600 timesharing terminals on a pair of 10 MHz processors is
>pretty slick.  (Come to think of it, over 9000 timesharing terminals
>on a single Alpha-based descendant of that system is mighty
>impressive, too.)

Wasn't the standard Plato hookup 2000 baud?  My last exposure to the
terminals was back when they still had plasma screens.  Very cool, those--I
wonder if there are any still around.

Cheers,
Chuck