On Sat, 24 May 2008 00:05:16 +0000 (UTC), Rick Jones
wrote:

I am reasonably confident that DEC did not invent RISC. I'm not sure
if IBM invented the concept of RISC, but they did have an early RISC
processor - the 801 IIRC. It was in the IBM "PC-RT" which those enough
"fortunate" to be at CMU ca 1984-1988 could use as an "Andrew"
workstation. They were generally third in preference among users
(well at least me, based on performance) behind Sun 3/80's and DEC
MicroVax II's.

....From http://en.wikipedia.org/wiki/Risc#Early_RISC :

"The first system that would today be known as RISC was not at the
time; it was the CDC 6600 supercomputer, designed in 1964 by Jim
Thornton and Seymour Cray. Thornton and Cray designed it as a
number-crunching CPU (with 74 opcodes, compared with a 8086's 400)
plus 12 simple computers called "peripheral processors" to handle I/O
and most other operating system functions. The CDC 6600 had a
load-store architecture with only two addressing modes
(register+register, and register+immediate constant). There were
eleven pipelined functional units for arithmetic and logic, plus five
load units and two store units (the memory had multiple banks so all
load-store units could operate at the same time). The basic clock
cycle/instruction issue rate was 10 times faster than the memory
access time.

Another early load-store machine was the Data General Nova
minicomputer, designed in 1968.

The earliest attempt to make a chip-based RISC CPU was a project at
IBM which started in 1975. Named after the building where the project
ran, the work led to the IBM 801 CPU family which was used widely
inside IBM hardware. The 801 was eventually produced in a single-chip
form as the ROMP in 1981, which stood for Research OPD [Office
Products Division] Mini Processor. As the name implies, this CPU was
designed for "mini" tasks, and when IBM released the IBM RT-PC based
on the design in 1986, the performance was not acceptable.
Nevertheless the 801 inspired several research projects, including new
ones at IBM that would eventually lead to their POWER system.

The most public RISC designs, however, were the results of university
research programs run with funding from the DARPA VLSI Program. The
VLSI Program, practically unknown today, led to a huge number of
advances in chip design, fabrication, and even computer graphics."

....The bit about RISC essentially originating with the "Cyber" jives
with what I was taught back in '76 when I first got indoctrinated into
what we of my High School's "Brain Trust" were getting into when we
were given accounts to access Texas University's CDC-6600. The catch
is that we were told the term "reduced instruction set", but the
acronym apparently came later. Of course, we were doing BASIC and
Minnesota Northstar Fortran IV in those days, so any reduction in our
instruction sets involved trying to code as fast as we could to keep
the dial-up costs down to a semi-minimum :-P Ironically, I wouldn't
hear the term RISC mentioned again in a computer class until 1985 in a
Pascal class, when bimbo-emeritus "Dr." Nell Dale tried to claim
top-down design would make RISC easier and Pascal the language that
would make BASIC and C obsolete. Pushing bull**** like that explains
why it wasn't until she retired from teaching that Texas U's CS degree
was finally accredited with a BS as opposed to the BA founded on pure
BS that it had been for years.

OM
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