DEC KS10 implementation - was CDC 6600 emulation

Rob Doyle radioengr at
Tue Jun 21 12:46:45 CDT 2016

On 6/21/2016 8:15 AM, Lee Courtney wrote:
> "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.

I don't know. I suspect it wouldn't be very different. The KS10 FPGA
CPU is about 4x faster than the DEC KS10.

Having said that, the RP06 Disk can be conditionally compiled in one
of two modes: "fast and loose" and "slow but accurate".

The "slow but accurate" mode is required to pass many of the DSRPA
diagnostics. The FPGA simulates head motion (seek times), disk
rotation (search times), and data transfer rates.

I'm guessing that the physical delays in the disk drive dominate the
timing of the DSRPA diagnostic - and those delays should be pretty accurate.

The RP06 uses a Secure Digital Card (SDHC) as media. The "fast and
loose" mode just uses the SD Card with very little external delays.
That seems to be good enough for everything but everything except
the diagnostics and is consistent with the SIMH implementation.


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