Program abends - Computers for Smart People - page 23

6. Program abends
While studying computers at the State University of New York at Binghamton,
one of my classmates had a cat name Abend. Some other people I met had a cat name Cat
and a dog named Dog, which probably didn't take much thought. I thought Abend was
an appropriate name since we were studying computers. The word abend is a contraction
of the phrase abnormal end , which many programs and systems do and with which not
many people are happy. It means working overtime and on the weekend. If you read my
topic, Tick Tock, Don't Stop: A Manual For Workaholics , you probably know that
working more than thirty five hours a week doesn't thrill me too much. My second topic
on work, This Page Intentionally Left Blank - Just Like The Paychecks Of The
Workers , advocates a thirty-hour workweek, which I think is a better idea. You may have
heard of Timothy Ferriss's, The 4-Hour Workweek , but that may be a bit drastic and
cause a few headaches. I doubt that management would approve.
In information technology there are quite a few ways for abends to occur. A
program could encounter bad data when it is looking for a numeric field and instead finds
letters of the alphabet. The result is the program terminates. A system could run into a
space problem and the result is an abend. There could be an I/O problem in that a
program is reading a file on magnetic tape when the read fails. The cause may be
something as simple as the fact that the tape drive missed its normal maintenance
cleaning, but it could be something else.
There could be a disk crash or you could run into bad sectors on the disk and the
results could be really annoying. I had the hard drive on my personal computer replaced a
few summers ago and it wasn't much fun. The word crash seems to be another way of
saying that we had an abend because they are one and the same. I was editing a page of
this topic on my word processor when I tried to save what I had added and couldn't. The
only way out was shutting down and restarting, which resulted in my recent changes
being lost. And I thought computers were supposed to make our life easier.
Each of these possible scenarios has to be controlled. If not, there is no sense in
having a system because reliability is compromised. You might be spending more time
with your computer than if you had a manual system. Obviously there will be difficulties
from time to time and you will have to put up with the problems, but you need to do
everything possible to limit these troubles.
To avoid space problems you have to maintain files, eliminating those that are out
of date or redundant. It may be as simple as backing up these questionable files to a tape
so that if they are needed, they can be retrieved. This leads to valuable space being saved.
Another kind of maintenance has to do with backing up a file and then redefining it and
restoring it from the backup. What this does is eliminate fragmentation, which happens to
files when they happen to have gaps in the data or be on multiple disk packs. One of the
maintenance tasks on PCs is checking for fragmentation on the disk from time to time
and taking action if necessary. Another way of helping alleviate the space problem is
eliminating duplicate data on a file, which I will get into later. There's much that can be
done and it will depend on your environment.