Core System Libraries

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As discussed in Chapter 1, Linux is merely the kernel of an operating system; the system libraries are what give an operating system the majority of its functionality. In this section, you will learn a bit about the core libraries used by Red Hat Linux 7.3.

Generally, users don't have to pay much attention to system libraries; they tend to be pretty static for the life of a release. That is, most bug fixes and similar upgrades occur in the userspace applications rather than in the system libraries. However, it is still important to know what system libraries are installed on your system, what they do, and any issues they might have.

Table 4-9 lists the most important RPM packages for Red Hat Linux 7.3 and some brief comments. This list includes not only the shared libraries that other programs link against, but also some of the key utility programs, such as the bash command shell and the fileutils package. Table 4-9 is actually organized by RPM package name—each entry in the table is packaged as its own RPM. Each RPM package, meanwhile, also contains many actual libraries (which are files with an extension of ".so") and related support files. This table should be viewed as a starting point rather than a comprehensive reference. The hardest part of learning about the core system libraries is just figuring out which libraries are the most important; that's what this table is providing. Readers should check the web sites, man pages, and other documentation to learn about the actual libraries.

Table 4-9: Red Hat Linux 7.3 Core Library Packages

PACKAGE

VERSION

COMMENT

XFree86

4.2.0

X Window System; v4 contains 3-D acceleration and new rendering extensions

glibc

2.2.5

Core runtime system libraries; contains linker/loader, math libraries, security libraries, network libraries, and multithreading libraries

bash

2.05a

Bourne Again SHell; primary system shell (used by root)

util-liunx

2.10s

Linux-specific disk, process management, and user tools

PAM

0.75

Pluggable Authentication Modules; used to log users in against various data stores (e.g., LDAP, RADIUS, and so forth)

gdbm, db2, db3

1.8.0, 2.4.14, 3.3.11

File database libraries; used by other programs to index and store data

fileutils

4.1

Binary utilities; contains basic programs such as ‘ls’, ‘cp’, ‘rm’, and so forth

It's worth noting the origins of some of these packages. As you know from reading Chapter 1, the Free Software Foundation's GNU project provided much of the software that made Linux usable. Linux, meanwhile, provided the kernel that GNU lacked. Libraries and programs such as these are concrete examples of the GNU contribution. The gdbm, fileutils, bash, and glibc packages are all GNU software. Notably, XFree86 is not; the GNU project still lacks its own X Window implementation. (XFree86 is discussed in more detail in the next section.)



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Tuning and Customizing a Linux System
Tuning and Customizing a Linux System
ISBN: 1893115275
EAN: 2147483647
Year: 2002
Pages: 159

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