> On May 7, 2021, at 2:34 AM, Al Kossow via cctalk <cctalk@classiccmp.org>
> wrote:
>
> On 5/6/21 7:35 PM, Chris Zach via cctalk wrote:
>
>> Ah well. I don't think it was evil marketing or VAX monsters that killed the
>> KC10, it was simply the fact that the amazing instruction set couldn't be
>> pipelined to make it more efficient for hardware and the memory management
>> system wasn't as efficient as the pdp11/Vax MMU concept.
>
> I've never found any documentation on what System Concepts did to make faster
> systems. Just crank up the clock speed?
> DEC was already using ECL.
Speaking of ECL: DEC did some amazing work with ECL VLSI in the early 1990s.
There was an R&D project called "BIPS" (for "billion instructions per second")
-- which aimed to build a single-chip processor that would run at a gigahertz.
That was way faster than the clock speeds of the time, and the notion was that
to do this you needed to use ECL logic. But there wasn't any large scale
integration with ECL, so DEC set out to create that. Part of the problem was
that each ECL fab had its own design rules, and those fabs were a shaky
business (not enough volume). That meant creating a CAD system which could
adjust the design to a new set of design rules quickly.
They built an interesting hybrid system where you could write the design partly
as geometries (for things like memory cells), partly as transistors, partly as
gates, and partly as C code. I remember an example, where they had a
transistor schematic for a single-bit latch, and then wrapped it in a loop:
"for (i=0; i < 64; i++) { <schematic> }". The magic was that (apart from the
few bits of explicit geometry-level design) it was all parameterized, so they
could regenerate the actual wafer geometry overnight for a new fab. The CAD
system also allowed extracting a behavioral model from the design.
The original plan, if I remember right, was to build an Alpha with this
technology. That morphed into building a MIPS, and I think they might have
gotten that to work.
Another part of the puzzle was figuring out how to feed 100 watts of power to a
chip, and get rid of that amount of heat, neither of which were anywhere close
to what was done at the time. I still have some of the tech reports that
describe that piece (and I contributed a wild idea -- which unfortunately DEC
didn't get around to patenting before the project was shut down).
paul
