> 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...


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