Hi Ioannis,

> OS: 4.4 i386.
> 
> Some days ago, in the usual local email I am getting with system log,
>  I saw kernel errors mentioning bad sectors. I have a usual 80 GB 
> IDE Western Digital HD.
> 
> Can I expect that the HD moves bad sectors out of circulation, or 
> have I to locate and mark bad sectors explicitly?

It is time you did some analysis.

Use smartmontools. Depending on your distribution this may or may not be 
installed.

Try this:

# smartctl -a /dev/hda

and see what you get. If your drive is recognised (in the smartctl 
database), then run the following:

# smartctl -t short /dev/hda

and see the progress of it using:

# watch "smartctl -l selftest /dev/hda"

it starts at 100% and works it's way down to zero. See how it runs through. 
If a short test passes, try a "long" test.

If your hard drive is not in the smartctl database or the smartctl you're 
using in your distribution is old (v5.33 or less) go to 
smartmontools.sourceforge.net and download the latest (compile or use RPM).

If you have an error on your drive during the short or long tests (read 
error or whatever), then further work can be done to correct this.

If you need more help feel free to email me directly with your smartctl 
output or join the smartmontools mailing list for the most knowledgeable 
people about this. smartmontools also has a "bad block howto" to help you 
recover from disasters.

Regards,

Michael.