Glossary

child process

The process resulting from a fork() and exec() sequence of system calls. The process that initiated the fork() is called the parent.

exec()

A system call that, when invoked, transfers the attributes and resources of the currently executing process to another (presumably different) program specified as a parameter of the system call. In this way new processes are made.

fork()

A system call that creates a near-exact (everything but PID) duplicate of the currently executing process. Used in conjunction with exec() to start up new programs.

gid

Group id. Numeric value associated with some group identity. Specified in /etc/group.

hard link

A second (or third, or fourth ) inode that points to a file.

inode

The data structure used by Linux to store information about files.

jihad

Holy war (e.g., "My operating system can beat up your operating system").

local

When used as an adjective, implies that the associated noun (e.g., drive, printer) is attached to the current actual physical machine, and not accessed via the network.

major device number

Number used by the kernel to specify which device driver is associated with a particular device.

minor device number

Number used by the kernel to distinguish among a group of devices all using the same driver.

parent process

The process that initiates a fork() system call that ultimately results in a child process.

process

An executing program.

PID, process id

Numeric value used by the system to uniquely identify a process.

PPID, process parent id

PID of the process that created the current process.

priority

Numeric value associated with a process used in computing who will next be allocated CPU time. Default is 0, negative values imply higher priority, and positive values lower priority.

recursive

Something that refers to itself is said to be recursive. In the context of computer science, the term is usually used in reference to a function or algorithm that, as part of its execution, calls itself.

sammich

Good, pleasant, useful (e.g., "Linux is very sammich"). Origins obscure.

soft link

A link to another path in the filesystem (aka symbolic link).

standard input

Where a program gets its input. By default, the keyboard, but may be attached to the output of another program.

standard output

Where a program sends its output. By default, the monitor, but may be attached to the standard input of another computer.

superuser

The user with a UID of zero, implying full access (read/write/ execute) to all system resources.

symbolic link

A link to another path in the filesystem.

system call

An invocation of a function provided by the operating system, for example, fork(), exec().

transparent

Not seen by the user. Typically has positive connotations; for example, "transparent access via NFS" means the user doesn't need to care that the filesystem is on a machine three thousand miles away.

uid

Numeric value used by the system to uniquely identify a user. Defined in the /etc/passwd file.

zombie processes

A process that is no longer executing but has not been removed from the table of executing processes.