8 Aug
2025
8 Aug
'25
2:26 p.m.
On 2025-08-08 2:23 p.m., Paul Koning wrote:
I need to read that.
I like IBM's book, on the 7030,
and Bell's Books,on the PDP computers.
Three totaly different views, on computing.
On Aug 8, 2025, at 2:14 PM, ben
<bfranchuk(a)jetnet.ab.ca> wrote:
On 2025-08-08 11:52 a.m., Paul Koning wrote:
You should spend some time looking at old machine architectures, because what you say is
very 21st century centric. An excellent intro is "Design of a computer - the
Control Data 6600" by J. E. Thornton. Available on Bitsavers
https://bitsavers.org/pdf/cdc/cyber/books/DesignOfAComputer_CDC6600.pdf or you can get the
hardcover printed book.
The 6600 max memory was 128k 60-bit words, which
for those days was admittedly quite large. No VM, though it did support relocation (base
address and field length, similar to the DEC KA10). Large RAM is nice but I don't see
what it has to do with RISC.
It was DRAM in SIMM packaging, that let you have a
fast memory bus off the cpu chip set. It's a great machine to study because it does an
amazing job of matching up parts of the design to wring the most performance out of the
available components. To pick one example: the primary clock period is 100 ns, and most
operations take only a few cycles. A new instruction can start every 100 ns, best case.
The memory system is designed so it can push data around at that speed. Process context
switch requires 16 word read/write operations, and that process is skillfully pipelined so
it normally runs in 16 consecutive cycles, spread over the memory banks (16 banks in the
minimal system, 32 in the full memory config). And so on.
It doesn't require SIMMs or a "cpu chip set" to go fast.
paul
All I can say is both RISC and SIMMs came about all at the same
time.That was when you had a mess of 86's, 286's,386, 16 and 32 bit
buses and optional math co-processors.
At my end of the world I was lucky to have a AT clone at that time,
since I spent my money on a COCO III.( OS/9 level II).
Gone in to TTL/PAL/CPLD home brewing for 18 bits of pure
fun/joy/headbanging. Now I am spending all my money on PCB's that don't
work, after the first few minutes.Heat? Noise? Bus? Bad CPLD routing? 5V
wall wart?Poor bypassing. Are there any tricks to using ATF1508's.
Ben.