Date:  Sun, 28 Jan 1996 13:54:25 -0700

From:  William King <WFKING[AT SYMBOL GOES HERE]CCIT.ARIZONA.EDU>

Subject: legacy



I've always associated the term "legacy" with software. The businesses

that implemented computer systems in the 1960's were typically huge with

huge data bases. Rather than replace earlier programs, they updated them.

There are problems with this. The earlier programs were written with the

limitations of the hardware in mind. Earlier programs made use of commands

such as "goto" which, by the time I was studying IBM COBOL in the early '80s,

was considered a command of last resort. Another problem was that code

was written for equipment that was replaced (air traffic control apparently

does not have this problem) by programmers who had since left with the

logic that motivated the code. Later code could be incompatible with

earlier code, or earlier code that was deemed a problem would be deleted

only to result in other problems six months later.

The biggest problem coming up with legacy software is not Windows '95

but rather the year 2000. Many really big systems out there interpret

the last two numbers of the year as the year. The 00 of 2000 for many

computers will be read as 1900 unless this is corrected. "The date of

birth of the individual you have claimed as a deduction on line...

etc." I think that this usage will prevail given the circumstances.

Bill King