Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!samsung!emory!tridom!atssc!fang!tarpit!bilver!dandrews
From: dandrews@bilver.uucp (Dave Andrews)
Newsgroups: comp.lang.asm370
Subject: Re: Postholes
Message-ID: <1991Apr16.175718.14777@bilver.uucp>
Date: 16 Apr 91 17:57:18 GMT
References: <1991Apr16.004355.22971@redsox.bsw.com>
Organization: W. J. Vermillion - Winter Park, FL
Lines: 33

In article <1991Apr16.004355.22971@redsox.bsw.com> campbell@redsox.bsw.com (Larry Campbell) writes:
>Why is it (he wonders out loud) that the only machines on which people still
>(in this day and age) seem to use assembly language are IBM 360s?
> [ text deleted ]
>Is it just because IBM doesn't ship any decent compilers?  I mean, what
>am I missing?  Why do people put up with this stuff?

Speaking for some of us MVS persons, there are access methods and supervisor
services and exit points that are ONLY available to assembly language users.
Some of this is because there have been some fairly recent architectural
changes to the S/360 line that the high-level-language guys haven't caught
up on, but mostly it is due to inertia, plain and simple.

SAS Institute has a C compiler that is purported to be suitable for
systems programming, and IBM has announced that their own C compiler
can do the same trick.  Basically, if you use a severely restricted
subset of functions, you don't have to have the runtime libraries
available.

Still and all, it is a trick.  Control blocks have to be interpreted in
your favorite HLL, and their formats are changeable and delivered only
in - you guessed it - assembly language DSECTs.  The SAS product claims
to be able to fairly automatically translate DSECTs into structures, but
I don't think this works very well.  NOTE: I haven't used their system,
but studied the documentation when it first came out.

BTW, assembly language is used elsewhere.  You cannot do systems stuff
for Mess-DOS machines in C without being able to appreciate the code
that is being generated for you.

Yes, it is an unwholesome mess, but it keeps me employed.

- David Andrews       tarpit!bilver!dandrews