> On Oct 17, 2016, at 1:42 PM, Clem Cole <cl...@ccc.com> wrote: > > > On Mon, Oct 17, 2016 at 12:35 PM, Paul Koning <paulkon...@comcast.net> wrote: > That doesn't excuse sloppy work. > > Agreed - and you will rarely see me defend Seymour. His systems were fast, > but they were not programmer friendly in any way IMO. Heck the man never had > an assembler - he did not think it was needed, he used programmed in octal. > > As I said, close enough for government work seemed to be his mantra; and as > long as the US National Labs kept buying from him, clearly he was getting > feedback that was an ok way to design. > > Then again our own old employer, DEC took a long time to get around to using > an IEEE FP scheme. While DEC was much better at arithmetic than CDC/Cray ever > was, it was not until the PMAX and Alpha that DEC started to support IEEE. > My old friend and colleague Bob Hanek (whom I used to joke as the Mr. > Floating Point), once said to me at lunch, he thought trying to get correct > results from the Vax FP unit made him lose his hair. Note that Bob was > hardly a great fan of IEEE either, he can regale you with stories of issues > with it also. As I an OS guy, I would smile and just say, I'll thankfully > leave that you guys in the compiler and runtime.
While IEEE is a good design, it clearly is not the only possible good design. I remember that DEC had a math algorithms team that specifically focused on correct (last bit accurate) algorithms for all the various math functions. I forgot the name of the leader of that group; first name Mary. It may be that they couldn't make that work with pre-IEEE DEC float, but I don't know. I tended to avoid floating point. Heck, I rarely used signed integers... I still remember chatting with a former classmate who at DEC one late night was busy testing packed decimal exponentiation algorithms. I asked "why the #$* do you need those?" He replied: for compound interest in COBOL programs. Oh yes... Duh... paul _______________________________________________ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh