1 Dec
2014
1 Dec
'14
12:47 p.m.
From: Eric Smith
Sent: Monday, December 01, 2014 4:05 AM
On Mon, Dec 1, 2014 at 4:57 AM, Lars Brinkhoff
<lars at nocrew.org> wrote:
> Rich Alderson <RichA at
LivingComputerMuseum.org> writes:
>> I worked at XKL for 10 years before coming to
my present job 11
>> years ago. Putting the Toad-1 into an FPGA was an experiment when I
>> left.
> It was? During my stint at XKL, I was told the
Toad-1 I was working
> with was an FPGA implementation. Maybe it was an experiment, but it
> seemed to work pretty well. But then, I was a telecommuter, so maybe
> some information was jumbled in long-distance transmission.
You guys probably have more information about this
than I do, but my
understanding was that the Toad-1 CPU required multiple FPGAs, CPLDs,
and other logic, while the Toad-2 CPU is a single FPGA.
Lars, Eric is correct. The Toad-1 is a multi-board computer system (at
minimum, the XKL-1 CPU, one XMG-1 memory, one XNI-1 Ethernet interface,
and one XRH-1 SCSI interface, in a 7-slot backplane). Each board used
several programmable parts, from Altera and Xilinx. In particular, the
CPU was a pair of Xilinx parts for the microcode engine, with an AMD
2900 family sequencer (I forget the particular part number).
The Toad-2 (and the 1U rack mount unit is *not* a Toad-2, but it does
contain two of them, thus the label) is a single FPGA implementation of
the Toad-1 (mutatis mutandis: no SCSI, but it talks to SD cards, for
example).
Rich
Rich Alderson
Vintage Computing Sr. Systems Engineer
Living Computer Museum
2245 1st Avenue S
Seattle, WA 98134
mailto:RichA at LivingComputerMuseum.org
http://www.LivingComputerMuseum.org/