27 Sep
2012
27 Sep
'12
10:39 a.m.
From: Dave McGuire
Sent: Wednesday, September 26, 2012 2:05 PM
On 09/26/2012 03:34 PM, Ethan Dicks wrote:
> I would be happy enough with something small like
an SC-25 - it's just
> going to be a single-user workstation, really. Given the size and the
> scarcity, I think if I ever run native 36-bit hardware, it's going to
> be an FPGA implementation, and to me, at least, that's one step more
> interesting than software emulation. I emulate because I must, but
> I'd love to run the real thing.
Well, XKL's TOAD-1 is "an FPGA
emulation", strictly speaking. It's
much more "grown up", though, than somebody spending a year working on
the VHDL or Verilog, then copping out and squirting it into a friggin'
eval board but never designing any hardware. ;)
Not, strictly speaking, true. The FPGAs + AMD 29xx sequencer in the XKL-1
CPU implement a microcode engine, and the extended PDP-10 architecture is
then implemented in microcode just as in the KL-10 and KS-10 processors.
The later XKL-2 processor, implemented in a single FPGA, is much closer
to what Ethan means, I would think, although still microcoded. The ucode
is part of the overall loadup of the FPGA from ROM at power-up.
Perhaps Ethan has in mind something more like what Neil Franklin attempted
a decade ago, or "dgcx" more recently.
Rich Alderson
Vintage Computing Sr. Systems Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104
mailto:RichA at vulcan.com
mailto:RichA at LivingComputerMuseum.org
http://www.LivingComputerMuseum.org/