DEC KS10 implementation - was CDC 6600 emulation

Lee Courtney leec2124 at
Tue Jun 21 10:15:38 CDT 2016

"When run on the target FPGA, the DSRPA diagnostic completes in
slightly less than 9 minutes."

Any idea what the run-time would be a on a real KS10?

Lee C.

On Tue, Jun 21, 2016 at 1:18 AM, Rob Doyle <radioengr at> wrote:

> On 6/20/2016 9:07 PM, ben wrote:
>> On 6/20/2016 9:43 PM, Eric Smith wrote:
>>> On Mon, Jun 20, 2016 at 9:34 PM, ben <bfranchuk at>
>>> wrote:
>>>> My other pet-peave is that every thing is point and click wizard
>>>>  for any useful modules. Need a rom module or adder module, point
>>>>  and click no portable code.
>>> I predominantly use Xilinx, and I don't use much point-and-click
>>> at all. I do all my HDL editing in emacs, including instantiating
>>> any of the Xilinx-provided IP blocks. My main interaction with the
>>>  Xilinx software (whether ISE or Vivado) is to click the "generate
>>>  bitstream" button.  It's even possible to do that from the command
>>>  line or a Makefile, but I haven't bothered.
>>> Do you use Static or Dynamic ram with the FPGA's? Ben.
> Another example -
> The KS10 FPGA uses 36-bit wide 166 MHz synchronous static RAM (SSRAM)
> for main memory. Main memory is as fast as the "Fast ACs". I didn't
> bother to implement cache (why bother?) and the Cache Diagnostic still
> whines that things that should not be cached are being cached...
> Most good tools can infer about everything from a well written HDL
> description. This includes single port and multi-port memory and
> includes RAM and ROM. The less tool-specific things that you use, the
> more portable your design is.
> The only IP block that I regularly use is a phased-locked-loop block.
> The DEC KS10 used a lot of asynchronous parts (memory, FIFOs/SILOs,
> one-shots, delay lines, RC delays, etc) that don't map very well to
> modern components - especially FPGAs. I've elected to redesign circuitry
> as necessary to use the FPGA resources. Others have elected to retain
> the original design as close as possible and accept the consequences.
> The KS10 FPGA is at:
> The ALU out of the KS10 FPGA describes a fairly complex circuit
> containing memory, registers, multiplexers, shifters, adders, including
> an am2901 4-bit slice processor-based ALU all written using generic
> Verilog. Also the HDL description has trace tags back to the card,
> schematic sheet, and reference designators of the original design - if
> you'd like to compare the two.
> The KS10 FPGA ALU design can be viewed at:
> Regarding simulation - a full Verilog simulation of the DEC RP06 disk
> diagnostic (DSRPA) requires about two and a half weeks to complete on my
> fastest computer. That's maybe not suprising because that simulates the
> entire CPU running the diagnostic program, memory, the unibus adapters,
> the RH11 disk controller, the console terminal, and eight RP06 disk
> drives. When run on the target FPGA, the DSRPA diagnostic completes in
> slightly less than 9 minutes.
> Rob.
> doyle (at) cox (dot) net

Lee Courtney
+1-650-704-3934 cell

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