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From: Q4071@pucc.Princeton.EDU (Interface Associates)
Newsgroups: comp.sys.atari.st,comp.sys.ibm.pc
Subject: Re: (Yes my) SW Make it to the year 2000?
Message-ID: <8820@pucc.Princeton.EDU>
Date: 1 Jul 89 16:02:00 GMT
References: <382@amms4.UUCP> <754@mitisft.Convergent.COM>
Reply-To: Q4071@pucc.Princeton.EDU
Organization: Princeton University, NJ
Lines: 55
Disclaimer: Author bears full responsibility for contents of this article

In article <754@mitisft.Convergent.COM>, dold@mitisft.Convergent.COM (Clarence Dold) writes:

>This has degenerated into a discussion of whether 2000 is a leap year or not,
>but the real question of 'will your package survive' was addressed rather
>lightly.
>...
>I only know that I was rather surprised to find a former customer of mine
>calling for conversion assistance on a program that he has been using,
>unmodified, since 1979....
>Particularly if you have distributed source (which I did not), some pieces
>of your code will likely exist well into the future.

I had regarded the following story as computer folklore, until I spoke
with some people from a large, blue, company.

In 1961, a computer department, somewhere, wrote a package in assembler
(what else?) for an SOA machine, the IBM 704.

A couple of years later, the company converted to a 1401.  Because of the
high cost of conversion, an emulator was obtained so that critical code
could be run in emulation until it can be converted.  When the System/360
came out, one particular package had not yet been converted.  Since the
source code (some of which could not be found) was in a language that the
line programmers could not read, and since a 1401 emulator was being
obtained anyway, the still-functioning software was put up on the 704
emulator, which was run on the 1401 emulator running on the 360.  The
code in question survived the conversion to S/370 by the fact that
a) BC-mode is an emulation of S/360, and b) VM/370 emulates a 360 to
a virtual machine with EC-mode off.

As I said, I regarded the story as apocryphal, until, working on an
XA conversion project for a client, I came into contact with an IBMer
who claimed to have received a request for advice about running a
1401 emulator undre VM/XA/SP, using the MACHINE=370 option to emulate
a 370 (emulating a 360 (emulating a 1401 (emulating a 704))).

His advice?  CONVERT ALREADY!

Another possible source of this story is the fact that much code for
the Census Bureau, IRS and air traffic control were written for
machines of that era.  Given budgetary constraints, much old code HAS
been emulated on newer machines, and I have little doubt that some of
it made it through two levels of emulation.

In fact, the number of programs which are designed to run, still, in 360
mode which have yet to be converted to XA (or even to 370-EC mode),
while XA is itself in the process of being superceded by ESA, even as
we read this, is testimony the the enduring nature of
software, epsecially in a commercial environment.


=========================================================================
Robert A. West c/o Interface Associates, Inc.    (Q4071@PUCC)
US Mail: 666 Plainsboro Rd. Office Commons, Suite 1A, Plainsboro NJ 08536
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