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<H2><A NAME="Introduction and General Information"></A> <A NAME="s1">1. Introduction and General Information </A></H2>

<P>
<H2><A NAME="What is Linux?"></A> <A NAME="ss1.1">1.1 What is Linux? </A>
</H2>

<P>Linux is the free Unix written from scratch by Linus Torvalds with
assistance from a loosely-knit team of hackers from across the
Internet.  Linux aims towards POSIX compliance, and has all of the
features you would expect of a modern, fully fledged Unix: true
multitasking, virtual memory, shared libraries, demand loading,
shared, copy-on-write executables, proper memory management, and
TCP/IP networking.
<P>Linux runs mainly on 386/486/586-based PC's, using the hardware
facilities of the 80386 processor family (TSS segments, et al.) to
implement these features.  Ports to other architectures are
underway. (See, ``
<A HREF="#What ports to other processors are there?">What ports to other processors are there?</A>
'')
<P>See the Linux <CODE>INFO-SHEET</CODE> for more details.  (``
<A HREF="Linux-FAQ-2.html#Where can I get the HOWTO's and other documentation?">Where can I get the HOWTO's and other documentation?</A>
'')
<P>The Linux kernel is distributed under the GNU General Public
License. (``
<A HREF="#Is Linux public domain?  Copyrighted?">Is Linux public domain?  Copyrighted?</A>
'')
<P>-------------------------------------------------------------------------------
<H2><A NAME="Where do I start?"></A> <A NAME="ss1.2">1.2 Where do I start? </A>
</H2>

<P>There are a handful of major Linux distributions.  For information
about them, and how they are installed, see Matthew Welsh's
<EM>Installation and Getting Started</EM>, or IGS for short.  It's
located at the Linux Documentation Project Home Page, 
<A HREF="http://sunsite.unc.edu/LDP">http://sunsite.unc.edu/LDP</A>.
<P>There is also an Installation HOWTO on the LDP Home Page.  
<P>Most of the distributions are available via anonymous FTP from various
Linux archive sites.  (``
<A HREF="Linux-FAQ-2.html#Where can I get Linux material by FTP?">Where can I get Linux material by FTP?</A>
'') There are also a large number of other releases which are
distributed less globally that suit special local and national needs.
<P>-------------------------------------------------------------------------------
<P>
<H2><A NAME="What software does Linux support?"></A> <A NAME="ss1.3">1.3 What software does Linux support? </A>
</H2>

<P>Linux supports GCC, Emacs, the X Window System, all the standard Unix
utilities, TCP/IP (including SLIP and PPP), and all of the hundreds of
programs that people have compiled or ported to it.
<P>There is a DOS emulator, called DOSEMU.  The latest stable release is
0.98.1.  The FTP archives are at 
<A HREF="ftp://ftp.dosemu.org/dosemu">ftp://ftp.dosemu.org/dosemu</A>.
The Web site is htmlurl url="http://www.dosemu.org"
name="http://www.dosemu.org">. 
<P>The emulator can run DOS itself and some (but not all) DOS
applications.  Be sure to look at the <CODE>README</CODE> file to
determine which version you should get.  Also, see the
<CODE>DOSEMU-HOWTO</CODE> (slightly dated at this point--it doesn't cover
the most recent version of the program), at 
<A HREF="ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO">sunsite.unc.edu/pub/Linux/docs/HOWTO</A>.
<P>Work has been progressing on an emulator for Microsoft Windows binaries.
(``
<A HREF="Linux-FAQ-3.html#Can I run Microsoft Windows programs under Linux?">Can I run Microsoft Windows programs under Linux?</A>
'')
<P>iBCS2 (Intel Binary Compatibility Standard) emulator code for SVR4 ELF and
SVR3.2 COFF binaries can be included in the kernel as a compile-time
option.  There is information at
<A HREF="ftp://tsx-11.mit.edu/pub/linux/BETA/ibcs2/README">tsx-11.mit.edu/pub/linux/BETA/ibcs2/README</A>.
<P>For more information see the <CODE>INFO-SHEET</CODE>, which is one of the
HOWTO's (``
<A HREF="Linux-FAQ-2.html#Where can I get the HOWTO's and other documentation?">Where can I get the HOWTO's and other documentation?</A>
'' and, ``
<A HREF="Linux-FAQ-5.html#How do I port XXX to Linux?">How do I port XXX to Linux?</A>
'')
<P>Some companies have commercial software available, including Motif.  They
announce their availability in comp.os.linux.announce--try searching
the archives.  (``
<A HREF="Linux-FAQ-2.html#Are the newsgroups archived anywhere?">Are the newsgroups archived anywhere?</A>
'')
<P>-------------------------------------------------------------------------------
<P>
<H2><A NAME="Does Linux run on my computer?  What hardware is supported?"></A> <A NAME="ss1.4">1.4 Does Linux run on my computer?  What hardware is supported? </A>
</H2>

<P>Giving Linux a try requires a machine with an Intel '386, '486, or
'586 processor with at least 2Mb of RAM and a single floppy drive.  To
do anything useful, more RAM and disk space is needed.  (``
<A HREF="#How much memory does Linux need?">How much memory does Linux need?</A>
'')
<P>VESA Local Bus and PCI are supported.  
<P>MCA (IBM's proprietary bus) and ESDI hard drives are mostly supported.
There is further information on the MCA bus and what cards Linux
supports on the Micro Channel Linux Web page, 
<A HREF="http://glycerine.itsmm.uni.edu/mca">http://glycerine.itsmm.uni.edu/mca</A>.
<P>Linux runs on '386 family based laptops, with X on most of them.  There
is a Web page at 
<A HREF="http://www.cs.utexas.edu/users/kharker/linux-laptop/">http://www.cs.utexas.edu/users/kharker/linux-laptop/</A>.
<P>For details of exactly which PC's, video cards, disk controllers, etc.
work see the <CODE>INFO-SHEET</CODE> and the <CODE>Hardware-HOWTO</CODE>.
(See ``
<A HREF="Linux-FAQ-2.html#Where can I get the HOWTO's and other documentation?">Where can I get the HOWTO's and other documentation?</A>
'')
<P>There is a port of Linux to the 8086, known as the Embeddable Linux
Kernel Subset (ELKS).  This is a 16-bit subset of the Linux kernel
which will mainly be used for embedded systems.  See 
<A HREF="http://www.linux.org.uk/Linux8086.html">http://www.linux.org.uk/Linux8086.html</A> for more information.
Linux will never run fully on an 8086 or '286, because it requires
task-switching and memory management facilities not found on these
processors.
<P>Linux supports multiprocessing with Intel MP architecture.  See the
file <CODE>Documentation/smp.tex</CODE> in the Linux kernel source code
distribution.
<P>See the next question for a (probably incomplete) list of hardware
platforms Linux has been ported to.
<P>-------------------------------------------------------------------------------
<P>
<H2><A NAME="What ports to other processors are there?"></A> <A NAME="ss1.5">1.5 What ports to other processors are there? </A>
</H2>

<P>There is a reasonably complete list of Linux ports at 
<A HREF="http://www.ctv.es/USERS/xose/linux/linux_ports.html">http://www.ctv.es/USERS/xose/linux/linux_ports.html</A>, and at 
<A HREF="http://www.linuxhq.com/dist-index.html">http://www.linuxhq.com/dist-index.html</A>.
<P>A project has been underway for a while to port Linux to suitable
68000-series based systems like Amigas and Ataris.  The Linux/m68K
FAQ is located at 
<A HREF="http://www.clark.net/pub/lawrencc/linux/faq/faq.html">www.clark.net/pub/lawrencc/linux/faq/faq.html</A>.  The URL of the
Linux/m68k home page is 
<A HREF="http://www.linux-m68k.org">www.linux-m68k</A>.
<P>There is a linux-680x0 mailing list. (``
<A HREF="Linux-FAQ-2.html#What mailing lists are there?">What mailing lists are there?</A>
'')
<P>There is (or was) a FTP site for the Linux-m68k project on 
<A HREF="ftp://ftp.phil.uni-sb.de/pub/atari/linux-68k">ftp.phil.uni-sb.de/pub/atari/linux-68k</A>, but this address may
no longer be current.
<P>Debian GNU/Linux is being ported to Alpha, Sparc, PowerPC, and ARM
platforms.  There are mailing lists for all of them.  See
<A HREF="http://www.debian.org/MailingLists/subscribe">http://www.debian.org/MailingLists/subscribe</A>.
<P>One of the Linux-PPC project pages has moved recently.  Its location
is 
<A HREF="http://www.linuxppc.org">http://www.linuxppc.org</A>, and the archive site is 
<A HREF="ftp://ftp.linuxppc.org/linuxppc">ftp.linuxppc.org/linuxppc</A>.
<P>There is a Linux-PPC support page at 
<A HREF="http://www.cs.nmt.edu/~linuxppc/">www.cs.nmt.edu/~linuxppc/</A>.  There you will find the kernel that
is distributed with Linux.
<P>Apple now supports MkLinux development on Power Macs, based on OSF and
the Mach microkernel.  See 
<A HREF="http://www.mklinux.apple.com">http://www.mklinux.apple.com</A>.
<P>A port to the 64-bit DEC Alpha/AXP is at 
<A HREF="http://www.azstarnet.com/~axplinux/">http://www.azstarnet.com/~axplinux/</A>.  There is a mailing list
at vger.rutgers.edu.  (``
<A HREF="Linux-FAQ-2.html#What mailing lists are there?">What mailing lists are there?</A>
'')
<P>
<P>Ralf Baechle is working on a port to the MIPS, initially for the R4600
on Deskstation Tyne machines.  The Linux-MIPS FTP sites are 
<A HREF="ftp://ftp.fnet.fr/linux-mips">ftp.fnet.fr/linux-mips</A> and
<A HREF="ftp://ftp.linux.sgi.com/pub/mips-linux">ftp://ftp.linux.sgi.com/pub/mips-linux</A>. Interested people may
mail their questions and offers of assistance to 
<A HREF="mailto:linux@waldorf-gmbh.de">linux@waldorf-gmbh.de</A>.
<P>There is also a MIPS channel on the Linux Activists mail server and a
linux-mips mailing list.  (``
<A HREF="Linux-FAQ-2.html#What mailing lists are there?">What mailing lists are there?</A>
'')
<P>There are currently two ports of Linux to the ARM family of
processors.  One of these is for the ARM3, fitted to the Acorn A5000,
and it includes I/O drivers for the 82710/11 as appropriate.  The
other is to the ARM610 of the Acorn RISC PC.  The RISC PC port is
currently in its early to middle stages, owing to the need to rewrite
much of the memory handling.  The A5000 port is in restricted beta
testing.  A release is likely soon.
<P>For more, up-to-date information, read the newsgroup
<CODE>comp.sys.acorn.misc</CODE>.  There is a FAQ at 
<A HREF="http://www.arm.uk.linux.org">http://www.arm.uk.linux.org</A> 
<P>The Linux SPARC project is a hotbed of activity.  There is a FAQ
available from Jim Mintha's Linux for SPARC Processors page, 
<A HREF="http://www.geog.ubc.ca/sparclinux.html">http://www.geog.ubc.ca/sparclinux.html</A>.  The SPARC/Linux
archives are at 
<A HREF="ftp://vger.rutgers.edu/pub/linux/Sparc">vger.rutgers.edu/pub/linux/Sparc</A>.
<P>There is also a port (``Hardhat'') to SGI/Indy machines.  The URL is
<A HREF="http://www.linux.sgi.com">http://www.linux.sgi.com</A>.
<P>-------------------------------------------------------------------------------
<P>
<H2><A NAME="How much hard disk space does Linux need?"></A> <A NAME="ss1.6">1.6 How much hard disk space does Linux need?  </A>
</H2>

<P>About 10Mb for a very minimal installation, suitable for trying Linux, and not
much else.
<P>You can fit an installation that includes X into 80Mb.  Installing
Debian GNU/Linux takes 500Mb--1GB, including kernel source code, some
space for user files, and spool areas.
<P>-------------------------------------------------------------------------------
<P>
<H2><A NAME="How much memory does Linux need?"></A> <A NAME="ss1.7">1.7 How much memory does Linux need? </A>
</H2>

<P>At least 4MB, and then you will need to use special installation
procedures until the disk swap space is installed.  Linux will run
comfortably in 4MB of RAM, although X Windows Apps will run slowly
because they need to swap out to disk.
<P>Some recent applications, like Netscape, require 64MB of physical
memory.
<P>-------------------------------------------------------------------------------
<P>
<H2><A NAME="How much memory can Linux use?"></A> <A NAME="ss1.8">1.8 How much memory can Linux use? </A>
</H2>

<P>A number of people have asked how to address more than 64 MB of
memory, which is the default upper limit.  Place the following in your
lilo.conf file:
<PRE>
append="mem=XXM"    
</PRE>

Where "XX" is the amount of memory, specified as 
megabytes; for example, '128M'.  For further details, see the lilo
manual page.  
<P>-------------------------------------------------------------------------------
<P>
<H2><A NAME="Is Linux public domain?  Copyrighted?"></A> <A NAME="ss1.9">1.9 Is Linux public domain?  Copyrighted? </A>
</H2>

<P>The Linux kernel copyright belongs to Linus Torvalds.  He has placed
it under the GNU General Public License, which basically means that
you may freely copy, change, and distribute it, but you may not impose
any restrictions on further distribution, and you must make the source
code available.
<P>This is not the same as Public Domain. See the Copyright FAQ, 
<A HREF="rtfm.mit.edu/pub/usenet/news.answers/law/copyright">rtfm.mit.edu/pub/usenet/news.answers/law/copyright</A>, for
details.
<P>Full details are in the file <CODE>COPYING</CODE> in the Linux kernel
sources (probably in <CODE>/usr/src/linux</CODE> on your system).
<P>The licenses of the utilities and programs which come with the
installations vary.  Much of the code is from the GNU Project at the Free
Software Foundation, and is also under the GPL.
<P>Note that discussion about the merits or otherwise of the GPL should
be posted to the news group <CODE>gnu.misc.discuss</CODE>, and not to the
<CODE>comp.os.linux</CODE> hierarchy.
<P>===============================================================================
<P>
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