[Techtalk] Debugging/ Troubleshooting book

hobbit at aloss.ukuu.org.uk hobbit at aloss.ukuu.org.uk
Thu Aug 1 12:03:07 EST 2002

On Wed, Jul 31, 2002 at 04:50:10PM +0000 or thereabouts, Carla Schroder wrote:
> On Wednesday 31 July 2002 09:22 pm, hobbit at aloss.ukuu.org.uk wrote:
> > > to find the appropriate patch, service pack, or magic combination of
> > > reboots and incantations, because applications are allowed to hose the
> > > OS, thereby introducing a million zillion skillion possible interactions.
> > > Unlike the Unix world, where such interactions are much more limited,
> >
> > I'm not sure about this. I think distros deliberately limit the
> > possible combinations by shipping only one or two or so possible
> > apps out of twenty or so apps which all perform the same function.
> > Examples are MTAs (which send mail between machinces), MUAs (which
> > you use to read mail), window managers, ftp clients, ftp servers,
> > editors and shells... and a billion other things.
> What I meant was, apps on Windows are much more intermingled with the OS, 
> that is why there are so many zillions of unintended consequences and 

Ah, I see. Right.

> botches. The most famous example is .dll hell. For those unfamiliar with 
> Windows shared libraries, differing versions have the same name: foo.dll can 
> actually have a hundred different incarnations, and often does. Applications 

!? Seriously? Knowing nothing about Windows, I never realised that.

> install these at will and overwrite the existing ones, which often breaks 
> other apps.
> Not like the sane Unix world, where different versions of a shared library 
> are named differently: foo.so.1.1, foo.so.1.2, etc. In the sane Unix world, 
> apps are not allowed to modify system files, as they do in Windows.

I understand now, and I see exactly what you mean. From the reaction
in the Linux and UNIX world when someone releases an app with the same 
version number, let alone a revision of a library which doesn't do 
what you said, it never occurred to me that there was any way other
than this so.1, so.2 and so on thing.

> > > Sometimes apps have their own troubleshooting utilities, that check
> > > syntax and file permissions and such.
> >
> > Oooh. I haven't met these. Can you give an example or two?
> Amanda and Postfix, to name two off the top of my head. Apache. Probably 
> others too.

Okay. Sold. For the next back-up run, I shall try Amanda. Just to
try this :) 

> For me, the biggest thing is learning the existing Unix utilities. 
> My gosh, there's a utility for every damn thing in the world! It's 
> a treasure hunt. I browse Running Linux and Linux In A Nutshell just 
> to find new ones. 

I just wait until I make a typo. 

I did not initially discover Usenet by trying to do 'rm' and hitting'
'rn' instead, but I know people who did. I found 'mc' when trying to
move (mv) files. Trying to list a directory, I invoked the linker and
was told I had a bad magic number, which gave me a laugh. (ls/ld)
And then there was the cd/dc mix-up. "Where has my prompt gone?"
Et cetera, et cetera.


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