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Re: Linus Torvalds at the Pearly Gates



On Thu, 1 Apr 1999, Jonathan Hayward wrote:
> 
> 1: XFree86 was downgraded from 3.3.3 to 3.3.2.1.  3.3.3 supports my
> video

Apt will not downgrade any package, I don't believe. You mean that the X
package overwrote your manually installed copy. (Not to nitpick, just
trying to clarify so we are all on the same page.)

> 2: /dev/eth0 no longer exists, and I cannot locate anything in the
>    documentation telling how to regenerate that or some equivalent
>    device.  MAKEDEV, for instance, did not recognize eth0 as a
> parameter.

eth0 is not a /dev/ file, it's a network interface. It is brought up by
scripts in /etc/init.d, specifically /etc/init.d/network. However, you
must have support for your ethernet card in the kernel...

Have a look at the ethernet HOWTO.

> This is really frustrating...  I can see a plausible reason for the
> first
> to have happened (specifically, since I did not install 3.3.3 through
> dpkg, it thought that the files were its own), but that blindness can
> and
> should be avoidable.

This is considered user error. If you want to install unpackaged software,
you have to use /opt or /usr/local or the like. There is no way for Apt or
dpkg to handle any random thing you install, so they don't try. Instead
you are guaranteed that Debian packages will not alter /opt or /usr/local.
Apt's internals require strict control over all dependencies; that's why
it refuses to run if you have broken dependencies.

>  One mechanism I can think of OTOH would be for the database to keep
> checksums of the files for earlier versions, so that it can at least
> ask before clobbering something which does work and replacing it with
> something which doesn't work.  

90% of the time this would just be annoying (not to mention it would slow
things down and fill disk space), and Debian has other means of handling
it, see below...

> If this behavior isn't changed, there
> should at least be an emphatically worded warning so that people don't
> lose their files.
> 

Can't argue with that, documentation could be enhanced. However, you can
get what you want without losing the power of Apt and dpkg.

Checksums are kept for "config files," which roughly means "files you are
allowed to change." So you can always change these safely. If you want to
change any other file, you have to run dpkg-divert to redirect the
packaged copy. You can find documentation on config files in the
"developer's corner" on the web site, and dpkg-divert --help is helpful.

In this particular case: you can get the latest video card support by
simply replacing XF86_SVGA (or your server) with a newer binary available
from www.xfree86.org. You can then dpkg-divert the package's version of
the server binary, or simply remember not to upgrade X.

I think the dpkg-divert command would be:
 dpkg-divert --add /usr/X11R6/bin/XF86_SVGA

Later, when you upgrade your X package to one that supports your card, you
will want to dpkg-divert --remove the same file.

There are also newer unofficial X packages floating around somewhere, but
I don't remember the URL.

HTH,
Havoc



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