diff options
Diffstat (limited to 'sag-0.6.1-www/Invisible/sag-0.6/node6.html')
| -rw-r--r-- | sag-0.6.1-www/Invisible/sag-0.6/node6.html | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/sag-0.6.1-www/Invisible/sag-0.6/node6.html b/sag-0.6.1-www/Invisible/sag-0.6/node6.html new file mode 100644 index 0000000..2255946 --- /dev/null +++ b/sag-0.6.1-www/Invisible/sag-0.6/node6.html @@ -0,0 +1,78 @@ +<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> +<!--Converted with LaTeX2HTML 96.1-h (September 30, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds --> +<HTML> +<HEAD> +<TITLE>Various parts of an operating system</TITLE> +<META NAME="description" CONTENT="Various parts of an operating system"> +<META NAME="keywords" CONTENT="sag"> +<META NAME="resource-type" CONTENT="document"> +<META NAME="distribution" CONTENT="global"> +<LINK REL=STYLESHEET HREF="sag.css"> +</HEAD> +<BODY LANG="EN" > + <A NAME="tex2html363" HREF="node7.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="./next_motif.gif"></A> <A NAME="tex2html361" HREF="node5.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="./up_motif.gif"></A> <A NAME="tex2html355" HREF="node5.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="./previous_motif.gif"></A> <A NAME="tex2html365" HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="./contents_motif.gif"></A> <A NAME="tex2html366" HREF="node114.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="./index_motif.gif"></A> <BR> +<B> Next:</B> <A NAME="tex2html364" HREF="node7.html">Important parts of the </A> +<B>Up:</B> <A NAME="tex2html362" HREF="node5.html">Overview of a Linux </A> +<B> Previous:</B> <A NAME="tex2html356" HREF="node5.html">Overview of a Linux </A> +<BR> <P> +<H1><A NAME="SECTION00310000000000000000">Various parts of an operating system</A></H1> +<P> + A UNIX operating system consists of a <b>kernel</b> and some + <b>system programs</b>. There are also some <b>application + programs</b> for doing work. The kernel is the heart of the operating + system<A NAME="tex2html5" HREF="footnode.html#125"><IMG ALIGN=BOTTOM ALT="gif" SRC="./foot_motif.gif"></A>. It keeps track + of files on the disk, starts programs and runs them + concurrently, assigns + memory and other resources to various processes, receives packets + from and sends packets to the network, and so on. The kernel does + very little by itself, but it provides tools with which all + services can be built. It also prevents anyone from accessing + the hardware directly, forcing everyone to use the tools it provides. + This way the kernel provides + some protection for users from each other. The tools provided + by the kernel are used via <b>system calls</b>; see manual page + section 2 for more information on these. +<A NAME="127"> </A> +<A NAME="128"> </A> +<A NAME="129"> </A> +<A NAME="130"> </A> +<A NAME="131"> </A> +<P> + The system programs use the tools provided by the kernel to + implement the various services required from an operating system. + System programs, and all other programs, run `on top of the kernel', + in what is called the <b>user mode</b>. + The difference between system and application programs is one + of intent: applications are intended for getting useful things + done (or for playing, if it happens to be a game), whereas + system programs are needed to get the system working. A word + processor is an application; <tt>telnet</tt><A NAME="305"> </A> is a system program. + The difference is often somewhat blurry, however, and is important + only to compulsive categorizers. +<A NAME="134"> </A> +<P> + An operating system + can also contain compilers and their corresponding libraries (GCC and + the C library in particular under Linux), although not all + programming languages need be part of the operating system. + Documentation, and sometimes even games, can also be part of it. + Traditionally, the operating system has been defined by the + contents of the installation tape or disks; with Linux it is + not as clear since it is spread all over the + FTP sites of the world. +<A NAME="135"> </A> +<A NAME="136"> </A> +<A NAME="137"> </A> +<A NAME="138"> </A> +<A NAME="139"> </A> +<P> +<HR><A NAME="tex2html363" HREF="node7.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="./next_motif.gif"></A> <A NAME="tex2html361" HREF="node5.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="./up_motif.gif"></A> <A NAME="tex2html355" HREF="node5.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="./previous_motif.gif"></A> <A NAME="tex2html365" HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="./contents_motif.gif"></A> <A NAME="tex2html366" HREF="node114.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="./index_motif.gif"></A> <BR> +<B> Next:</B> <A NAME="tex2html364" HREF="node7.html">Important parts of the </A> +<B>Up:</B> <A NAME="tex2html362" HREF="node5.html">Overview of a Linux </A> +<B> Previous:</B> <A NAME="tex2html356" HREF="node5.html">Overview of a Linux </A> +<P><ADDRESS> +<I>Lars Wirzenius <BR> +Sat Nov 15 02:32:11 EET 1997</I> +</ADDRESS> +</BODY> +</HTML> |