Writing error messages? Take II

["Hart, Geoff" <Geoff-H -at- MTL -dot- FERIC -dot- CA>]

Iain observes:

<<I don't think that I have ever seen that message [Abort, retry, fail]
without a preceding line that tells me what has gone wrong. Something like:
Drive a: not ready Abort, retry, fail?>>

Sorry, I was imprecise. Without a _useful_ description of what has gone
wrong. Why isn't the drive ready? Is it broken? Is it busy? Is it not
responding for some unknown reason? Did it complete part of the task I asked
it to do and the fail midway along?

<<Abort = give up this bit of the task, retry = try again, fail = give up
this bit of the task and report the device as not working>>

That's all very well as a starting point, but the logic quickly falls apart
if you dig deeper. The only difference you've noted between abort and fail
is that "fail" reports the device is not working--but I already know that
(either because I'm frustrated by the device's failure to do what I told it
to do or because I've just read the cryptic message that tells me that the
device isn't responding), so why would I want to be told this again? It's
redundant! Plus, which part of the task didn't work: accessing the drive,
preparing it for a copy or read operation, or actually trying to copy or
read from a defective disk? "Retry" is no better: if it didn't work the
first time, why would it work now? I want to know _why_ it didn't work (if
it's possible to know that) and what I can do about it. Worse yet, this
message usually occurs at a very stressful time (e.g., while trying to make
a backup copy that may never get made), and occasionally crashes badly
without giving you a chance to recover if you retry a few times. So yes, it
_is_ as bad a message as I suggested. About the only worse message I've seen
was "This error should never happen", and that one is probably apocryphal.

--Geoff Hart, FERIC, Pointe-Claire, Quebec
geoff-h -at- mtl -dot- feric -dot- ca

Hofstadter's Law: The time and effort required to complete a project are
always more than you expect, even when you take into account Hofstadter's
Law.