Chapter 3 Study Cards Flashcards
Advanced Package Tools (APT)
A package management tool that’s most often used atop Debian packages, although a version for RPM also exists. APT enables package installation and updates from Internet repositories, including automatic dependency resolution.
APT
A package management tool that’s most often used atop Debian packages, although a version for RPM also exists. APT enables package installation and updates from Internet repositories, including automatic dependency resolution.
APT suite
The APT suite of tools includes a program, apt-cache, that’s intended solely to provide information about the Debian package database (known in Debian terminology as the package cache).
Berkeley Internet Name Domain (BIND)
A common Domain Name System (DNS) server for Linux.
BIND
A common Domain Name System (DNS) server for Linux.
Build number
A number identifying minor changes made to a binary package by its maintainer rather than changes implemented by the program’s author, which are reflected in the version number.
Checksum
A simple file integrity check in which the values of individual bits or bytes are summed up and compared to a stored value for a reference version of the file.
Debian package
A package file format that originated with the Debian distribution but is now used on several other distributions. Debian packages feature excellent dependency tracking and easy installation and removal procedures.
Dependency
A requirement of one software package that another one be installed. For instance, most Linux programs include a dependency on the C library.
Dynamic library
A type of library that’s stored as a separate file from an executable program but that’s loaded along with the main program file. Dynamic libraries save disk space and RAM compared to static libraries.
General Public License (GPL)
A common free software license, created and favored by the Free Software Foundation.
glibc
A specific type of C library used on Linux systems since the late 1990s.
GNOME
A common desktop environment for Linux, headquartered at http://www.gnome.org.
GNU C library (glibc)
A specific type of C library used on Linux systems since the late 1990s.
GNU Network Object Model Environment (GNOME)
A common desktop environment for Linux, headquartered at http://www.gnome.org.
GNU’s Not Unix (GNU)
A project sponsored by the Free Software Foundation to create a free implementation of Unix. Linux relies heavily on GNU software-so much so that some people prefer the term GNU/Linux to Linux.
GPL
A common free software license, created and favored by the Free Software Foundation.
Hung
Term used to describe a program that’s stopped responding to user input, network requests, or other types of input to which it should respond. Hung processes sometimes consume a great deal of CPU time.
jobs
The jobs command displays minimal information about the processes associated with the current session.
K Desktop Environment (KDE)
A common desktop environment for Linux, headquartered at http://www.kde.org.
KDE
A common desktop environment for Linux, headquartered at http://www.kde.org.
kernel
The core of an operating system, which provides multitasking (process creation, interprocess protection, interprocess communication), memory management, and basic I/O management.
kill
The kill command is the tool to terminate a process. This program sends a signal (a method that Linux uses to communicate with processes) to a process. The signal is usually sent by the kernel, the user, or the program itself to terminate the process.
libc
A library of standard functions that can be used by all C programs.
Library
A collection of code that’s potentially useful to many programs. This code is stored in special files to save disk space and RAM when running programs that use the library.
Load average
A measure of the demand for CPU time by running programs. A load average of 0 means no demand for CPU time; 1 represents a single program placing constant demand on the CPU; and values higher than 1 represent multiple programs competing for CPU time. (On multi-core CPUs, the load average can equal the number of cores before CPU-time competition begins.) The top and uptime commands both provide load average information.
Logical block addressing (LBA)
A method of accessing data on a disk that uses a single sector number to retrieve data from that sector. LBA contrasts with cylinder/head/sector (CHS) addressing. Some sources refer to LBA as linear block addressing.
Package
A collection of files stored in a single carrier file, ready for installation using a package management system such as RPM or the Debian package system.
Path
A colon-delimited list of directories in which program files may be found. (Similar lists define the locations of libraries, fonts, and other file types.)
Process
A piece of code that’s maintained and run by the Linux kernel separately from other pieces of code. Most processes correspond to programs that are running. One program can be run multiple times, resulting in several processes.
Release number
A number identifying minor changes made to a binary package by its maintainer rather than changes implemented by the program’s author, which are reflected in the version number.
Root Directory
The directory that forms the base of a Linux filesystem (meaning 2). All other directories are accessible from the root directory, either directly or via intermediate directories.
RPM
The most popular package manager in the Linux world is the RPM Package Manager (RPM). RPM is also available on non-Linux platforms, although it sees less use outside the Linux world.
Samba
The standard Windows interoperability suite of programs for Linux and Unix.
Shared library
A type of library that’s stored as a separate file from an executable program but that’s loaded along with the main program file. Dynamic libraries save disk space and RAM compared to static libraries.
Signal
In reference to processes, a code that the kernel uses to control the termination of the process or to tell it to perform some task. Signals can be used to kill processes.
Source code
The version of a program written by a human and typically stored in plaintext (ASCII) file format. A compiler converts source code to a binary form that a computer can run.
Tarball
A package file format based on the tar utility. Tarballs are easy to create and are readable on any version of Linux and on most non-Linux systems. They contain no dependency information, and the files they contain aren’t easy to remove once installed.
Yum
Yum is one of several meta-packagers, it enables you to easily install a package and all its dependencies using a single command line.
