Fairchild FST-2?

From: Neil Macmillan <neil.macmillan_at_freeuk.com>
Date: Mon Dec 24 09:16:33 2001

The Fairchild FST-2 computer was used to control a family of
Semiconductor ( chip ) testers I guess from sometime in the mid 1970s to
around the mid 1980s. The family of testers were branded as "Sentry",
"Sentinel" and "Series10" ( maybe some others ).

The FST-2 was a 24-bit machine with its memory interleaved between odd
and even addreses. When the CPU was reading/writing to an odd address, a
peripheral could address an even address and vice-versa using DMA. Early
machines were booted from tape, but newer machines had a PROM boot board
which allowed booting from 8" floppy, hard-disk, tape ( and possibly a
network. ) Early machines had 25 bit wide memory with a parity bit,
while the later machines had 30 bit wide memory which provided error
detection and correction. Control of the tester was via two busses known
as the long-register bus and the short-register bus.

If you come across an FST-2 which can be powered up, set the console
switches ( piano keys ) to 06760000 in octal and press STOP, RESET, LDP,
LDC and START. The machine should waken up. There are a few stand-alone
FST-2s kicking around without any tester hardware. These were used as a
FACTOR compiler co-processor for a development system which was based on
the HP1000. Most FST-2s will be part of a chip tester. If the chip
tester is still working, the whole system is still quite valuable. Even
as a source of spares.

Although the tester has a lot of different power supplies the FST-2
probably ony needs 5.0V and the RS-232 voltages to get running.

The FST-2 ran an OS named M3 ( "M Cubed" ) and was programmed using a
FORTRAN-like language named FACTOR, ( Fairchild Algorithmic Compiler
Tester ORiented. ) Most Sentry testers could test digital chips with 60
pins up to 10 MHz. Some later Sentrys could test up to 120 pins at 20
MHz. I remember FST-2s being very slow to compile FACTOR programs. Most
users ended up compiling their program and test patterns (
Vectors/Truth-Tables ) on a VAX.

Fairchild ( and later Schlumberger ) provided really good in-depth
training and documentation for the CPU and the testers for hardware
maintenance and programming. The manuals which were up for grabs were
either manuals/schematics which were shipped with a tester, or training
manuals which some engineer picked up in San Jose or Munich.
Received on Mon Dec 24 2001 - 09:16:33 GMT