Re: Y2K Issues

[dewarr@my-dejanews.com]

In article <F22tqs.3q@jvdsys.nextjk.stuyts.nl>,
  jerry@jvdsys.nextjk.stuyts.nl (Jerry van Dijk) wrote:
> Most financial software that I am aware of was at that
> time not
> written in COBOL but PL/1. One reason this is stil done
> is to take
> advantage of it's 22 digits accuracy.


Of course this statement may be true, but it simply means
that your experience was by no means representative. PL/1
even at its most successful point, never held a very large
share of the financial software market, and was always
hugely overshadowed by COBOL.

There are many reasons for writing in PL/1 rather than
COBOL, but in practice the difference between the 18 vs 22
digits of accuracy is not a very significant one, and of
course certainly not relevant to the subject material of
this post.

Of course PL/1 does have much better data abstraction than
COBOL, so one might hope that PL/1 programs would be less
sensitive to Y2K problems. Unfortunately, many PL/1
programs were written in COBOL style, and PL/1 goes out of
its way to accomodate this style (e.g. allowing completely
general use of anonymous types as in COBOL). Thus most PL/1
programs are in practice as bad as COBOL when it comes to
Y2K problems, at least that is my experience.

Language can make a difference, but often it is not *just*
the language, but the general style and approach of the
programmers in that language that is as significant. In the
case of Ada (let's get back on topic :-) it is most
certainly true that the data abstraction in Ada encourages
writing programs that are either less likely to have Y2K
problems in the first place, or be much easier to correct
if such problems exist. However, the important point is
that the Ada culture is such that programmers are likely to
take full advantage of these abstraction capabilities.
COBOL style code in PL/1 does not seem horrible at all,
COBOL style code in Ada would be rather disgusting (I am
talking now specifically about the style of data
declaration and data abstraction).

Robert Dewar

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