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From: scottl@convergent.com (Scott Lurndal)
Newsgroups: comp.arch
Subject: Re: Computers for users not programmers
Message-ID: <2975@risky.Convergent.COM>
Date: 15 Feb 91 23:41:40 GMT
References: <3159:Feb1213:56:3091@kramden.acf.nyu.edu> <1991Feb12.192725.21029@Think.COM> <2922@risky.Convergent.COM> <1991Feb14.151831.15426@linus.mitre.org>
Sender: root@risky.Convergent.COM
Reply-To: scottl@convergent.com (Scott Lurndal)
Organization: Unisys Network Computing Group
Lines: 41

In article <1991Feb14.151831.15426@linus.mitre.org>, bs@linus.mitre.org (Robert D. Silverman)
writes:
|> In article <2922@risky.Convergent.COM> scottl@convergent.com (Scott Lurndal) writes:
|> :In article <1991Feb12.192725.21029@Think.COM>, barmar@think.com (Barry Margolin) writes:
|>  
|> stuff deleted.
|> 
|> :If you look at some of the dedicated COBOL engines (such as the UNISYS V-Series
|> :(old Burroughs Medium Systems) line), you will find that the instruction set
|> :will not support C with any efficiency at all, and FORTRAN is marginal.
|> :
|> :The point?  You cannot design a processor which is all things to all people
|> :(the swiss army knife processor - (well the B1900 was a good start)).  If you 
|> :design a processor around any particular language, you have reduced the 
|> :overall usefullness of that processor.   Some of the current risc chips are
|> :quite fast with scientific/systems applications (using C/Fortran/Pascal, et. al.);
|> :but performance falls rapidly when you start running COBOL applications which
|> :require translation from BCD<->binary before and after each arithmetic op.
|> :
|>  
|> Yes. However, if DOUBLE PRECISION integer arithmetic were supported, the
|> need for BCD would totally disappear. Not only that, the integer arithmetic
|> would be at least an order of magnitude FASTER. There is no inherent reason
|> why the dollars and cents calculations [read: extended precison] cannot be
|> done in integer arithmetic.
|>
What about all the data files, and millions of 9-track tapes which contain
BCD data?   There is conversion cost involved here if you cannot just read and
use it as is.  

On architectures which support BCD, the programmer understands the layout
of data items in memory, and via the 88 level items, redeclares (a la union)
a section of memory in another form (e.g. to split dollars and cents, et. al.)
This clearly would require more than just a recompile to work at all.  88-level
items are heavily used in COBOL applications.

|> Bob Silverman
|> #include <std.disclaimer>
|> Mitre Corporation, Bedford, MA 01730
|> "You can lead a horse's ass to knowledge, but you can't make him think"
Scott Lurndal, UNISYS Corporation  - I can't even speak for myself....