Loadable Modules

$ lsmod

Module ide-cd cdrom soundcore parport_pc lp parport autofs smc-ultra 8390

nls_iso8859-1 nls_cp437

Size Used by 27072 0 (autoclean) 28512 0 (autoclean) [ide-cd]

25600 1 (autoclean) [parport_pc lp] 11520 0 (autoclean) (unused) 5792 1

4464 0 (autoclean) 14768 1 (autoclean) 6416 0 (autoclean)

6752 0 [smc-ultra] 2832 1 (autoclean) 4352 1 (autoclean)

vfat fat ext3 jbd

9584 1 (autoclean)

32384 0 (autoclean) [vfat]

64624 3

40992 3 [ext3]

Loadable modules perform a variety of tasks. Some modules are hardware device drivers, such as the smc-ultra module for the SMC Ultra Ethernet card. Other modules provide support for the wide array of filesystems available in Linux, such as the ISO8859 filesystem used on CD-ROMs or the DOS FAT filesystem with long filename support (vfat).

Each entry in the listing produced by the lsmod command begins with the name of the module followed by the size of the module. As the size field indicates, modules are small. Often, they work together to get the job done. The interrelationships of modules are called module dependencies, which are an important part of properly managing modules. The listing tells you which modules depend on other modules. In our sample, the smc-ultra driver depends on the 8390 module. You can tell that from the 8390 entry, but not from the smc-ultra entry. The 8390 entry lists the modules that depend on it under the heading Used by.

Most of the lines in Listing 1.7 contain the word autoclean. This means that a module can be removed from memory automatically if it is unused. autoclean is only one of the module options. You can select different options when manually loading modules.

Was this article helpful?

0 0

Post a comment