Glossary (DRAFT)

"The Librarian of the Unseen University had unilaterally decided to aid comprehension by producing an Orang-utan/Human Dictionary. He'd been working on it for three months. It wasn't easy. He'd got as far as `Oook.'" (Terry Pratchett, ``Men At Arms'')

This is a short list of word definitions for concepts relating to Linux and system administration.


The act of writing funny sentences in the hope of getting them into the Linux cookie file.

application program

Software that does something useful. The results of using an application program is what the computer was bought for. See also system program, operating system.


A process lurking in the background, usually unnoticed, until something triggers it into action. For example, the update daemon wakes up every thirty seconds or so to flush the buffer cache, and the sendmail daemon awakes whenever someone sends mail.

file system

The methods and data structures that an operating system uses to keep track of files on a disk or partition; the way the files are organized on the disk. Also used about a partition or disk that is used to store the files or the type of the filesystem.


A list of words and explanations of what they do. Not to be confused with a dictionary, which is also a list of words and explanations.


Part of an operating system that implements the interaction with hardware and the sharing of resources. See also system program.

operating system

Software that shares a computer system's resources (processor, memory, disk space, network bandwidth, and so on) between users and the application programs they run. Controls access to the system to provide security. See also kernel, system program, application program.

system call

The services provided by the kernel to application programs, and the way in which they are invoked. See section 2 of the manual pages.

system program

Programs that implement high level functionality of an operating system, i.e., things that aren't directly dependent on the hardware. May sometimes require special privileges to run (e.g., for delivering electronic mail), but often just commonly thought of as part of the system (e.g., a compiler). See also application program, kernel, operating system.