[Info-vax] Unexpected error using ZIP for OpenVMS

[AEF]

On Dec 22, 9:56 am, Steven Schweda <sms.antin... at gmail.com> wrote:
> > From the programming point of view, [...]
>
>    Good luck with that argument.  You're up against a fellow
> who seems to believe that a car which runs out of fuel and a
> car whose engine bursts into flame are essentially
> equivalent.  (Personally, I expect one of those events to
> happen in some ordinary circumstances, but not the other.)

OK, you're using "unexpected" to mean "very unlikely". Fair enough.
But when you strand yourself by running out of gas, I don't think
you're going to say you expected it!

> > An *unexpected error* from the programming point of view is
> > usually caused by a hardware fault or human error (disk
> > getting full). [...]
>
>    I wouldn't call a disk-full condition an unexpected error.
> If a program complained about a disk-full condition when the
> disk wasn't actually full, then _that_ would be unexpected.
> For example, some old versions of Zip on some system types
> might create a temporary archive on the wrong device or file
> system (typically in the current directory, instead of in the
> user-specified archive destination directory), so the user
> might get a disk-full complaint about a disk which the
> program shouldn't have been using.  The program might put out
> an accurate complaint about a condition which the program's
> author anticipated, but the condition occurred only because
> of a defect in the program, so an ordinary user would not
> expect the error.  Just as a user might not expect an error

The ordinary user would be puzzled. This would be a puzzling error.

When I encounter errors like this, I don't say to myself, "I wasn't
expecting that." I would instead say, "Why is this happening?"

> when Zip tries to read a perfectly normal Stream or Stream_CR
> file.

Also a puzzling error. First check the file. If the file is okay,
check the code.

OK, the muon was an unexpected discovery. (At that time, Nobel
laureate I. I. Rabi famously quipped, "Who ordered that?") The
analogous case in programming would be finding that a program could do
something you weren't expecting it to!

AEF