They do seem to talk specifically about IO processes!

Hmm. As a phrase "IO processes" doesn't make a lot of sense.

The lines you see, and the numbers in the first column under the heading "#" in Filemon, are IO events, not processes. The process IDs are appended to the filenames in the third column under the heading "Process". The best I can suggest to you is that you ask them by what measure they are deciding that you are using to much resource.

File::ReadBackwards isn't a standard module, but it is pure perl, so it is easy to install it in the same place as your scripts live, and use use lib './lib'; to allow it to be found. Assuming your scripts live in a subdirectory /cgi-bin, the you would create a directory structure and copy Backwards.pm from CPAN into it as follows:

/cgi-bin/lib/File/Backwards.pm
[download]

Then in your script you would have

use lib './lib';
use File::Backwards;
[download]

I seem to remember someone posting a more thorough explanation of this somewhere, but I could not find it via supersearch. Maybe someone else remembers it and will post a link.