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From: fouts@orville.nas.nasa.gov (Marty Fouts)
Newsgroups: comp.arch
Subject: Re: myths & magazines
Message-ID: <3425@ames.arpa>
Date: Tue, 17-Nov-87 12:27:12 EST
Article-I.D.: ames.3425
Posted: Tue Nov 17 12:27:12 1987
Date-Received: Thu, 19-Nov-87 20:59:45 EST
References: <56700004@ada-uts> <6745@apple.UUCP> <916@winchester.UUCP>
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Reply-To: fouts@orville.nas.nasa.gov.UUCP (Marty Fouts)
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In article <916@winchester.UUCP> mash@winchester.UUCP (John Mashey) writes:
>
>0) At the rate of speed this business moves, writers and editors
>are hard-pressed to keep up, even when they try very hard.

I would feel for these editors, except they do a generally bad job,
including both articles such as those cited and the way in which they
handle news releases.  Daily papers, which have a less than 24 hour
deadline handle news release rewrites with more accuracy than most
industry monthly or weekly papers.  It wouldn't bother me if it
happened occasionally, but every press release I've seen about my
organization has come out badly garbled.  Knowing the lack of accuracy
about what I can check, I've forced myself to doubt everything I read
in these magazines, which makes me like the man with two clocks.

>Since many of the trade rags are controlled circulation, you
>can't usefully threaten to cancel your subscription!
>

Actually you can, it just takes a lot more threats for them to do
something.  Controlled circulation magazines make their money off of
their advertisers, and the advertising rate depends heavily on
how well the market is targeted.  If enough people quit reading a bad
trade magazine, it will quit being published.

>5) In general, it is hopeless to improve some of the rags, which are
>little above the National Enquirer.  Some of the magazines try very hard,
>even to having their own benchmark suites which they want to watch
>running on a real machine.

A word about magazine benchmarking suites.  Byte magazine had an
article in the July 1987 issue which contained a benchmark comparison
of the 80386 and the 68020 which consisted of  a suite of five benchmarks.
They were all flawed in ways that the readership of this group is well
familiar with, but my favorite is one called float which contained
code like:

#define CONST1 3.141597E0
#define CONST2 1.7839032E4
#define COUNT 10000
double a, b, c;
int i;
a = CONST1;
b = CONST2;
for (i = 0; i < COUNT; ++i) {
  c = a * b;  /* These two statements are repeated a total of 12 times */
  c = c / a;  /* "So that the loop overhead is dominated by work" */
}

where the for loop is suppose to measure the C libraries ability to do
double precision floating point.  Over half the compilers I have tried
this code on recognize the loop invariance and constant propagation
and generate code to either statically allocate a, b and c or simple
store instructions at run time, making the code three runtime
instructions. (Which happen outside the timing loop . . .)