I'm using Slack 10.1 with new kernel 2.6.13, so far I understood that
if I want some modules to load/unload at boot, I need to edit
/etc/modprobe.conf or rc.modules.
What confuses me is that if I do 'lsmod' I get a list of some modules
, which I want to remove, that are not present in those two files.
For example I want to remove nvsound, orinoco_pci and so on
for some reason but they do not exist in modprobe.conf nor in
rc. modules.

Is there another file that I should be aware of?

Yes, they may be loaded by hotplug (/etc/rc.d/rc.hotplug) you could add those modules to hotplug's blacklist at /etc/hotplug/blacklist to avoid it load them.

Should I make blacklist executable?

I would also like to know where to find a list of those modules since I can't find them anywhere except in /lib/modules/2.6.13/modules.alias.
Is that the right list which loads them while system is booting?

No.

Hotplugging does not use a list. On the initial startup, it just collects al PCI/USB/Cardbus device IDs, and looks up if there is any module associated with a device ID. If this is the case, the module is loaded. After booting the system hotplugging is automatically triggered when a device is plugged. The kernel runs the hotplug binary that is set in /proc/sys/kernel/hotplug (normally /sbin/hotplug) with information about the event as environment variables. The same procedure is then repeated for this device (the ID is looked up, modules are loaded if needed).

If you want to have full control over what modules should be loaded, you can disable hotplug with

chmod a-x /etc/rc.d/rc.hotplug

Or just list any module you do not want to load in /etc/hotplug/blacklist .

even the module name is (for exemple) "ide-scsi", it's included in rc.modules as "ide_scsi" I don't know why but maybe you have the same problem

You can both use an underscore and a normal dash with the module tools.

When you use 'modprobe', it figures out if a module needs other modules loaded and loads them all in the right order. 'insmod', on the other hand, loads only the module that you specify.
If you want to load everything manually, do as suggested abbove and make /etc/rc.d/rc.modules non-executable and also empy out the modprobe.conf file or rename it.

I believe you can also use the "alias" statement in "/etc/modules.conf" to alias the module name being loaded to the correct module name (that you want to be loaded). If hotplug detects the device it will load the driver you specified in the "alias".

The ALSA sound drivers use that technique to load generic driver names and then alias the driver names to the correct driver names for the sound card.

I was quite confused about modules too.

rc.modules loads modules that are not automatically loaded.

modules.conf is used to specify options to always use when loading a module, or to alias a module name to a different name.

For example, if you use "insmod abcd" and there is an alias in "modules.conf" plus options specified there, you may actually end up with something like this.

insmod xyz irq=6 port=0x3fc

In this example "abcd" was aliased to "xyz" and there was an options statement specifying the "irq=6" and "port=0x3fc".

Since hotplug, modprobe (and other things?) load modules automatically, it's important to know what's in "modules.conf". Mine was empty when I installed Linux.