I'm interested in talking to anyone who has or had a National Semiconductor PACE or INS8900 system, or documentation or software for one. In order to have something halfway interesting to run on the homebrew IMP-16 system John List designed and built, I decided to start from PACE software, since the PACE architecture is derived from (but not binary-compatible with) the IMP-16, which itself was inspired by the Data General Nova. A few years ago a friend gave me a copy of the fig-FORTH listing for the PACE, which turned out to be missing a page. The listing is on Bitsavers, but a complete listing is now available on the fig-FORTH implementations page on forth.org: http://www.forth.org/fig-forth/contents.html Over the course of the last week, I typed in the fig-FORTH listing (both source and object code), wrote a PACE cross-assembler, assembled fig-FORTH and compared the generated object to what I typed in, fixed the errors, wrote a PACE simulator, and fixed the fatal bug in the "U/" word of the fig-FORTH listing. (Maybe no one other than the author ever actually ran PACE fig-FORTH?) Now that it's working I've just started trying to translate it for the IMP-16, which doesn't have the RADC and SUBB instructions of the PACE, and which has somewhat different shift, rotate, and flag instructions. Google doesn't turn up much about the PACE other than the few manuals and datasheets already on Bitsavers. I know that a paper tape based resident assembler existed, as well as a disk operating system with a resident assembler. There may have also been a BASIC interpreter. Eric