Post by Paul Sture Post by David J Dachtera Post by Tim Sneddon
Anyone seen this before? I thought it looked kind of interesting...
RT Logic is re-implementing VAX computer systems in FPGA for Hewlett
Packard. By leveraging HP's VAX intellectual property, RT Logic will
provide VAX single-board computers and peripherals to replace legacy
systems critical to the maintenance of NATO's Air Defense System.
Pardon my butting in...
I'm just dying to know what "FPGA" is.
I'm sure it's not "Female Professional Golf Assoc."
I *think* that these are Field Programmable Gate Arrays, where the
"Field programmable" bit means programmable by the customer.
It would appear to be a VAX processor built using a field
programmable gate array, rather than with fully- or semi-custom
integrated circuitry. That's not going to be a small FPGA, either. :-)
Chip designs can be fully custom semiconductor, semi-custom, or using
generic programmable hardware such as the FPGA. FPGA is the cheapest of
these three and very flexible, but there can be speed and scaling
problems; you won't get gonzo performance, but you do get flexibility.
You can implement the design of the using a chunk of non-volatile
storage loaded into the FPGA, and off you go. Make a mistake or have a
tweak in the design, and you don't need a whole new chip fabrication
pass, you just reprogram the gate array.
The DECvoice DTC04, DTC05 and DTCN5 modules used this technique, as
do many other devices, and the DECvoice boards could have different
microcode loaded into the on-board Xilinx FPGA to completely change the
behavior of the hardware. FPGA has come a whole long way since then.
As for other FPGA stuff, Dave Conroy (worked very briefly with Dave
eons ago, back in DEC VPG) was working on various FPGA versions of old
DIGITAL iron in eons past, but I don't know what happened to that work.
There are other FPGA-related projects, too. Here are some URLs:
Services for OpenVMS