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From: ccplumb@watmath.UUCP
Newsgroups: comp.arch
Subject: Brain-Clogging Decimal (Was: Re: Wirth's challenge (Was Re: RISC))
Message-ID: <15782@watmath.waterloo.edu>
Date: Tue, 8-Dec-87 18:57:49 EST
Article-I.D.: watmath.15782
Posted: Tue Dec  8 18:57:49 1987
Date-Received: Sun, 13-Dec-87 05:36:03 EST
References: <6901@apple.UUCP>
Reply-To: ccplumb@watmath.waterloo.edu (Colin Plumb)
Organization: U of Waterloo, Ontario
Lines: 35
Confusion: U(Waterloo), Ontario

In article <6901@apple.UUCP> baum@apple.UUCP (Allen Baum) writes:
>A small addendum: while the 801 may not have played an enormous role,
 [In the design of the HP precision architecture]
>System/370 certainly did! Many of the design decisions in Spectrum were in
>reaction to problems we saw (& measured & were told about) in the 370 
>architecture, from both IBM and Amdahl.

This got me thinking (with apologies for ever uttering anything faintly
resembling praise for IBM), that the 360/370/whatever architecture isn't
all that bad.  (Perhaps you can tell me via mail what the problems are.
I'm interested, but it would probably be ancient headgear to others.)

With the exception, of course, of all the packed decimal divide stuff.

The most recent processor family I know of that still faintly supports
BCD math is the 68000.  Hooray!  It seems people are finally realizing
that, while for simple procesing (say, adding up a payroll), the work
of binary <-> decimal conversion far exceeds the processing that's done
on the binary numbers, it isn't worth jumping through hoops in hardware
and software to avoid the translation.  The overhead is fixed and won't
kill your system.  Optimize somewhere else.  Surely you can improve the
disk buffering algorithm to detect sequential access and do read-ahead
and purge-behind.

Does anyone else have any ideas about COBO* (I can't bring myself to
say "Langauge") support in architectures?  Is is just hanging on like
bad smells and MS-DOS, or is it worth anything at all?
--
	-Colin (watmath!ccplumb)

(To the tune of "I don't know why she swallowed the fly")
I don't know why the process won't die.
Perhaps it's a BUG.

Verses, anyone?