diff options
Diffstat (limited to 'sag-0.6.1-www/sag-0.6.1.html/x83.html')
| -rw-r--r-- | sag-0.6.1-www/sag-0.6.1.html/x83.html | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/sag-0.6.1-www/sag-0.6.1.html/x83.html b/sag-0.6.1-www/sag-0.6.1.html/x83.html new file mode 100644 index 0000000..8f1face --- /dev/null +++ b/sag-0.6.1-www/sag-0.6.1.html/x83.html @@ -0,0 +1,189 @@ +<!DOCTYPE HTML PUBLIC "-//Norman Walsh//DTD DocBook HTML 1.0//EN"> +<HTML +><HEAD +><TITLE +>Important parts of the kernel</TITLE +><META +NAME="GENERATOR" +CONTENT="Modular DocBook HTML Stylesheet"><LINK +REL="HOME" +TITLE="The Linux System Administrators' Guide" +HREF="book1.html"><LINK +REL="UP" +TITLE="Overview of a Linux System" +HREF="c63.html"><LINK +REL="PREVIOUS" +TITLE="Overview of a Linux System" +HREF="c63.html"><LINK +REL="NEXT" +TITLE="Major services in a UNIX system" +HREF="x94.html"></HEAD +><BODY +BGCOLOR="#FFFFFF" +TEXT="#000000" +><DIV +CLASS="NAVHEADER" +><TABLE +WIDTH="100%" +BORDER="0" +CELLPADDING="0" +CELLSPACING="0" +><TR +><TH +COLSPAN="3" +ALIGN="center" +>The Linux System Administrators' Guide</TH +></TR +><TR +><TD +WIDTH="10%" +ALIGN="left" +VALIGN="bottom" +><A +HREF="c63.html" +>Prev</A +></TD +><TD +WIDTH="80%" +ALIGN="center" +VALIGN="bottom" +>Chapter 2. Overview of a Linux System</TD +><TD +WIDTH="10%" +ALIGN="right" +VALIGN="bottom" +><A +HREF="x94.html" +>Next</A +></TD +></TR +></TABLE +><HR +ALIGN="LEFT" +WIDTH="100%"></DIV +><DIV +CLASS="SECT1" +><H1 +CLASS="SECT1" +><A +NAME="AEN83" +>Important parts of the kernel</A +></H1 +><P +>The Linux kernel consists of several important parts: process + management, memory management, hardware device drivers, filesystem + drivers, network management, and various other bits and pieces. + <A +HREF="x83.html#KERNELOVERVIEW" +>Figure 2-1</A +> + shows some of them.</P +><DIV +CLASS="FIGURE" +><P +><B +><A +NAME="KERNELOVERVIEW" +>Figure 2-1. Some of the more important parts of the Linux kernel</A +></B +></P +><P +><IMG +SRC="overview-kernel.gif"></P +></DIV +><P +>Probably the most important parts of the kernel (nothing else + works without them) are memory management and + process management. Memory management takes care of assigning + memory areas and swap space areas to processes, parts of the + kernel, and for the buffer cache. Process management creates + processes, and implements multitasking by switching the + active process on the processor.</P +><P +>At the lowest level, the kernel contains a hardware device + driver for each kind of hardware it supports. Since the world is + full of different kinds of hardware, the number of hardware device + drivers is large. There are often many otherwise similar pieces + of hardware that differ in how they are controlled by software. + The similarities make it possible to have general classes of + drivers that support similar operations; each member of the class + has the same interface to the rest of the kernel but differs in + what it needs to do to implement them. For example, all disk + drivers look alike to the rest of the kernel, i.e., they all + have operations like `initialize the drive', `read sector N', + and `write sector N'.</P +><P +>Some software services provided by the kernel itself have + similar properties, and can therefore be abstracted into classes. + For example, the various network protocols have been abstracted + into one programming interface, the BSD socket library. Another + example is the <I +CLASS="GLOSSTERM" +>virtual filesystem</I +> (VFS) + layer that abstracts the filesystem operations away from their + implementation. Each filesystem type provides an implementation + of each filesystem operation. When some entity tries to use + a filesystem, the request goes via the VFS, which routes the + request to the proper filesystem driver.</P +></DIV +><DIV +CLASS="NAVFOOTER" +><HR +ALIGN="LEFT" +WIDTH="100%"><TABLE +WIDTH="100%" +BORDER="0" +CELLPADDING="0" +CELLSPACING="0" +><TR +><TD +WIDTH="33%" +ALIGN="left" +VALIGN="top" +><A +HREF="c63.html" +>Prev</A +></TD +><TD +WIDTH="34%" +ALIGN="center" +VALIGN="top" +><A +HREF="book1.html" +>Home</A +></TD +><TD +WIDTH="33%" +ALIGN="right" +VALIGN="top" +><A +HREF="x94.html" +>Next</A +></TD +></TR +><TR +><TD +WIDTH="33%" +ALIGN="left" +VALIGN="top" +>Overview of a Linux System</TD +><TD +WIDTH="34%" +ALIGN="center" +VALIGN="top" +><A +HREF="c63.html" +>Up</A +></TD +><TD +WIDTH="33%" +ALIGN="right" +VALIGN="top" +>Major services in a UNIX system</TD +></TR +></TABLE +></DIV +></BODY +></HTML +>
\ No newline at end of file |