Last updated: January 26th, 1998
I've been at this since 1972, when,
as a U.S. Air Force Computer Maintenance Technician, I worked
on a team of technicians that kept the AN/FSQ-31V SACCS DPC
operational. The AN/FSQ-31V SACCS DPC (usually just called the
"DPC") was the data processing and data base storage element
of the SAC Automated Command & Control System (SACCS) and
was comprised of a second-generation, i.e., transistorized,
version of the IBM 7090 mainframe computer. It had a 2.5us.
instruction cycle time, a 48-bit instruction/data word, 65K
words of "core" memory that was split between 4 16K banks that
were immersed in an oil bath, 15 magnetic tape drives, a 26MB
disk file system that was the size of a small car (Geo Metro)
and had 125 heads mounted on a hydraulicly operated head bar
that read and wrote to the 25 39" in diameter disks. The disks
were spun at 500 RPM by a 5HP electric motor, and the head
positioning system required a 50 gallon reservoir of aircraft
type hydraulic fluid. There were also 2 139K word capacity
vertical magnetic drums. The operator's console was something
like 18 feet long, and had a neon light for each flip-flop in
the cpu, high-speed I/O, low-speed I/O, memory, tape adapter,
disk adapter, drum interface, and miscellaneous devices. The
DPC was designed and installed around 1959, but because the
military typically keeps it's equipment for a long time, the
system wasn't replaced until 1977, when the WMCCS became
operational.
By that time, however, I had been re-assigned to a unit that
operated the ground station equipment that performed the command,
control, and communication functions for the Defense Meteoralogical
Satellite Program (DMSP) weather satellites. The whole thing was
very heavily computerized, and was based on Data General mini-computers
of the Nova-800J type, although there were a few Eclipse S230s around.
I eventually ended up at the Headquarters at Offutt AFB, near Omaha,
Nebraska, and got into writing telemetry analysis programs in
FORTRAN 5.
I finally got out of the Air Force in 1981, moved to Southern California,
and got a job writing software for the upgraded ground systems for the
DMSP. These were based on newer, more powerful multi-user systems,
predominatly 
MV8000s and MV10000s, using AOS/VS and
FORTRAN 77. I worked at various companies in the Southern California
Aerospace industry, on
VAXes,
PDP-11s, military computers,
microcprocessors, and test equipment. I also began building personal
systems around that time, starting with an IBM-PC XT type computer,
Intel Multibus systems configured
as personal development
boxes (running the iRMX-86 operating system and using PL-M/86 programming
language), as well as had my first exposure to C. So, over the span of
24 years I have maintained, programmed, operated, and built computers
of all different types, and have even taught computer systems
operation and electronic assembly.
Besides my hobby and professional interest in computers, I am interested
in electronics in general, and also claim
amateur (ham) radio as another
avocation, especially the marriage between the two - packet radio. Although
I haven't yet gotten a packet system up on the air, I have been busy collecting components
to construct an interface between my home PC, currently a 486-DX/66 based
system that runs Linux
the free Unix for the rest of us!
most of the time, although that is always subject to
change, and my RF equipment, currently just a
Radio Shack HTX-202.
� 1996 Chuck Harding 
charding at iguard dot com
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