> 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
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