[SOLVED] Google-Earth stopped working ...

[GreyGeek]

and gave the message "can find libfontconfig1.so.1".

It seems that during the last update apt-get left a message listing a dozen or so packages, saying that they were no longer used, and recommended using "sudo apt-get autoremove".

I did.

All seemed well until I needed to run Google-Earth. I ran "sudo apt-get install libfontconfig1:i386" (because the 64 bit version was installed but not useful to GE). It complained about configuration problems from a lot of packages I recognized as being in the list of "no longer used" packages. I did "sudo apt-get -f install and that brought everything back in. GoogleEarth began running again.

[NickStone]

I believe that when you use apt-get to update it performs a check of existing packages in its database and if it discoveres packages which have not been used that often it will tell the user that it is longer required and advises the user to use the auto-remove feature to get rid of all "not required" packages.

However, I believe that this is one of the flaws of the Debian APT system, because not all packages it reports as being "not required" are still required by some programs, especially libraries. It is quite "dangerous" to automatically remove all packages that APT informs you that are not required. I have had it in the past where APT had told me that libdvdcss was not required but I know that it was still required by my video player in order to play encrypted dvd's so I didn't use the auto-remove function in APT to get rid of it.

So a word of warning, don't blindly use the auto-remove feature in apt-get unless you know 100% that all packages in its list is not required.

[GreyGeek]

... So a word of warning, don't blindly use the auto-remove feature in apt-get unless you know 100% that all packages in its list is not required.

Could it be a recent regression?

Since I began using Kubuntu with 9.04 in January of 2009 I have always done the "autoremove" when apt-get said to use it. This was the first time it recommended that I remove active libraries. It may have been because I installed the 64 bit Debian package from the Google website (using qapt) instead of building it from the google-earth package builder in the repository and then running the dpkg command as instructed.

[GreyGeek]

GE had given me lots of problems for two or three years. Even though it would install, and the globe would appear and zoom in, when ever I put a term in the search box and clicked the search button I'd always get "malformed html". Could never find a fix. KWheezy, which I ran for two months (Nov & Dec of last year) ran GE just fine. When I switched back to Kubuntu it, too, ran GE fine ... until this "autoremove" problem. However, it is back to working great.

[SteveRiley]

I believe that when you use apt-get to update it performs a check of existing packages in its database and if it discoveres packages which have not been used that often it will tell the user that it is longer required and advises the user to use the auto-remove feature to get rid of all "not required" packages.

No, it's nothing so subjective as APT evaluating whether a package has or has not "been used that often."

Say you install package foo. If foo depends on bar, then APT will install bar first, then install foo. For each package installed on a system, APT sets a flag to indicate whether it was installed manually or automatically. Manual packages are those you intended to install; in the example here, foo is marked manual. Automatic packages are those installed to meet dependences; in the example here, bar is marked auto.

The command apt-get autoremove evalutes all currently installed packages and looks for any that are marked auto but lack an installed ancestor. Continuing with the example, if you removed foo, bar would still remain installed. If nothing else in the system needs bar, then autoremove will remove it.

However, I believe that this is one of the flaws of the Debian APT system, because not all packages it reports as being "not required" are still required by some programs, especially libraries. It is quite "dangerous" to automatically remove all packages that APT informs you that are not required. I have had it in the past where APT had told me that libdvdcss was not required but I know that it was still required by my video player in order to play encrypted dvd's so I didn't use the auto-remove function in APT to get rid of it.

autoremove will never remove a package that's a hard dependency of any other installed package. You are correct that libdvdcss2 is required for watching DVDs. However, for legal reasons, no distribution based on Debian can package this file. Therefore, no media player package can declare a hard dependency on it. In *buntu, a number of packages carry a hard dependency for libdvdread4, however. When you install this package, you can run the script sudo /usr/share/doc/libdvdread4/install-css.sh to download and install the libdvdcss2 package from Videolan.org. On my system, that package is marked manual:

steve@t520:~/junk$ apt-mark showmanual | grep libdvd
libdvdcss2

Thus, autoremove would never consider it to be a candidate for removal. I am unsure why on your system it would appear as a candidate for automatic removal. You can change its flag thusly: sudo apt-mark manual libdvdcss2.

[GreyGeek]