The term "legacy" HAS been misused in the recent past to imply
"outdated", but generally this was by those pushing non-mainframe server
platforms that didn't yet run any commercial applications that had been
productive for an extended period.
The correct usage of "legacy" is to describe that which is bequeathed to
the next generation (of users, application programmers, etc.). When
applied to computer software or applications, if the application is
still being used successfully, it is because it is regarded as an asset
to the company, not a liability. Every computer application system that
is put into production at that point becomes legacy code that will be
passed on as a corporate asset until it is replaced by another
application or can no longer be made to do useful work for the company
and is discarded. At that point the old code ceases to be part of the
corporate software legacy and simply becomes "obsolete". Using the
correct definition of legacy, IEFBR14 is most definitely legacy code.
As pointed out in the article, the advent of the S/360 and the
subsequent philosophy of upward compatibility made it possible for
legacy applications to persist for a much longer time. Prior to that
there was minimal compatibility for running the same applications on
faster hardware, and legacy applications had to be thrown out and
redesigned every year or so when you outgrew your existing computer
system and migrated to a new one. Computing would be much less
pervasive, much more expensive to use, and require massive application
programming support just to maintain fewer existing applications, if
mainframes had not made it possible to run legacy applications for
decades with minimal maintenance.
JC Ewing
Lindy Mayfield wrote:
Great article, and nice picture, too.
<rant>
I happen to disagree with the author's use of the word legacy in some places.
If I understand correctly, legacy means outdated. Hardware, such as an IBM 360
or a PDP-9 can be legacy. A file format, such as ISAM which is no longer
supported, I would think of as legacy. You could have legacy data on punch
cards or paper tape.
I'm talking about legacy the adjective, not the noun as in "IBM Mainframes have a
long legacy."
I would contend that if you have, for example, some assembler payroll modules
that were written in 1988 and still run today, then they aren't legacy until
you stop using them. Is IEFBR14 legacy code? I don't think so.
Is this just nit picking? I don't think so because using legacy as an adjective has a very negative connotation and is used so often to bash the mainframe. Now I don't think for a second in this article that is being done. Even the title Legacy Matters is an excellent description of what IBM has accomplished.
I cannot prove it, but I'm quite sure that the reason when I see written legacy machines, legacy data and the mainframe all mentioned together I automatically think it implies that they are at this time busy migrating everything over to windows servers, and this is all due to clever marketing that happened 10 years ago or more.
I'm not picking on this article. The only thing that they said that I thought
was illogical was referring to legacy software, and I think that if it is old
but still used it shouldn't be considered legacy. That's a nit.
What I am not happy with is how many times I see in technical literature,
powerpoints and other places the words legacy and mainframe used together. What
about, say, the software program I bought for Windows 98 that doesn't run on
XP? Now that's legacy!
Ok, sorry, I had to get that out of my system.
</rant>
Lindy
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED]
Sent: 12. heinäkuuta 2007 2:53
To: [email protected]
Subject: Legacy matters
FYI.
Interesting article:
Legacy matters: why the IBM mainframe continues to thrive
http://arstechnica.com/news.ars/post/20070711-legacy-matters-why-the-ibm-
mainframe-continues-to-thrive.html
...
--
Joel C. Ewing, Fort Smith, AR [EMAIL PROTECTED]
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