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.
Linux runs mainly on 386/486/586-based PCs, using the hardware facilities of the 386 processor family (TSS segments, et al.) to implement these features. Ports to other architectures are underway. (See `` What ports to other processors are there? '')
See the Linux INFO-SHEET for more details. (See ``
Where can I get the HOWTOs and other documentation?
'')
The Linux kernel is distributed under the GNU General Public License. (See, `` Is Linux public domain? Copyrighted? '')
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There are a handful of different Linux distributions. For information about them, and how they are installed, see Matthew Welsh's Installation and Getting Started, or IGS for short. It's located at the Linux Documentation Project Home Page, http://sunsite.unc.edu/LDP.
There is also an Installation HOWTO at the LDP Home Page.
Most of the distributions are available via anonymous FTP from various Linux archive sites. See `` Where can I get Linux material by FTP? '' There are also a large number of other releases which are distributed less globally, which suit special local and national needs.
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Linux supports GCC, Emacs, the X Window System, all the standard Unix utilities, TCP/IP (including SLIP and PPP), and all the hundreds of programs that people have compiled or ported for it.
There is a DOS emulator (available at
tsx-11.mit.edu/pub/linux/ALPHA/dosemu) which can run DOS
itself and some (but not all) DOS applications. Be sure to look at
the README file to determine which version of dosemu you
should get. Also, see the DOSEMU-HOWTO (slightly dated at
this point--it doesn't cover the most recent version of the
program), which is located at
sunsite.unc.edu/pub/Linux/docs/HOWTO.
Work has been progressing on an emulator for Microsoft Windows binaries. (See `` Can I run Microsoft Windows programs under Linux? '')
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. See the file tsx-11.mit.edu/pub/linux/BETA/ibcs2/README.
For more information see the INFO-SHEET, which is one of the
the HOWTOs (See ``
Where can I get the HOWTOs and other documentation?
'' See also ``
How do I port XXX to Linux?
''
Some companies have commercial software available, including Motif. They announce their availability in comp.os.linux.announce--try searching the archives. (See `` Are the newsgroups archived anywhere? '')
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You need a 386, 486 or 586, with at least 2Mb of RAM and a single floppy, to try Linux. To do anything useful, more RAM is needed. (`` How much memory does Linux need? '')
VESA Local Bus and PCI are supported.
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, http://glycerine.itsmm.uni.edu/mca.
Linux runs on 386 family based laptops, with X on most of them. There is a relevant Web page at http://www.cs.utexas.edu/users/kharker/linux-laptop/.
For details of exactly which PC's, video cards, disk controllers, etc.
work see the INFO-SHEET and the Hardware-HOWTO.
(See ``
Where can I get the HOWTOs and other documentation?
'')
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 http://www.linux.org.uk/Linux8086.html 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.
Linux supports multiprocessing with Intel MP architecture. See the
file Documentation/smp.tex in the Linux kernel source code
distribution.
See the next question for a (probably incomplete) list of hardware platforms that Linux has been ported to.
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There is a reasonably complete list of Linux ports at http://www.ctv.es/USERS/xose/linux/linux_ports.html, and at http://www.linuxhq.com/dist-index.html.
A project has been underway for a while to port Linux to suitable 68000-series based systems such as Amigas and Ataris. The Linux/m68K FAQ is located at www.clark.net/pub/lawrencc/linux/faq/faq.html. The URL of the Linux/m68k home page is www.linux-m68k.
There is a linux-680x0 mailing list. (See `` What mailing lists are there? '')
There is (or was) a FTP site for the Linux-m68k project on ftp.phil.uni-sb.de/pub/atari/linux-68k, but this address may no longer be current.
Debian GNU/Linux is being ported to Alpha, Sparc, PowerPC, and ARM. There are mailing lists for all of these platforms. See http://www.debian.org/MailingLists/subscribe.
One of the Linux-PPC project pages has moved recently. Its location is http://www.linuxppc.org, and the archive site is ftp.linuxppc.org/linuxppc.
There is a Linux-PPC support page at www.cs.nmt.edu/~linuxppc/. There you will find the kernel that is distributed with Linux.
Apple now supports MkLinux development on Power Macs, based on OSF and the Mach microkernel. See http://www.mklinux.apple.com.
A port to the 64-bit DEC Alpha/AXP is at http://www.azstarnet.com/~axplinux/. There is a mailing list at vger.rutgers.edu. (See `` What mailing lists are there? '')
Ralf Baechle is working on a port to the MIPS, initially for the R4600 on Deskstation Tyne machines. The Linux-MIPS FTP sites are ftp.fnet.fr/linux-mips and ftp://ftp.linux.sgi.com/pub/mips-linux. Interested people may mail their questions and offers of assistance to linux@waldorf-gmbh.de.
There is also a MIPS channel on the Linux Activists mailserver and a linux-mips mailing list. (See `` What mailing lists are there? '')
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.
For more up-to-date information, watch the newsgroup
comp.sys.acorn.misc. There is a FAQ at
http://www.arm.uk.linux.org
The Linux SPARC project is a hotbed of activity. There is a FAQ available from Jim Mintha's Linux for SPARC Processors page, http://www.geog.ubc.ca/sparclinux.html. The SPARC/Linux archives are at vger.rutgers.edu/pub/linux/Sparc.
There is also a port (``Hardhat'') to SGI/Indy machines. The URL is http://www.linux.sgi.com.
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About 10Mb for a very minimal installation, suitable for trying it out and not much else.
You can squeeze a more complete installation including X, into 80Mb. Installing almost all of Debian GNU/Linux takes around 500Mb, including kernel source code, some space for user files, and spool areas.
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At least 4MB, and then you will need to use special installation procedures. Linux will run comfortably in 4MB of RAM, although X Windows Apps will run slowly because they need to swap out to disk.
Some recent applications, like Netscape, require 64MB of physical memory.
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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:
append="mem=XXM"Where "XX" is the amount of memory, specified as megabytes, for example, '128M'. For further details see the lilo manual page.
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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.
This is not the same as Public Domain. See the Copyright FAQ, rtfm.mit.edu/pub/usenet/news.answers/law/copyright, for details.
Full details are in the file COPYING in the Linux kernel
sources (probably in /usr/src/linux on your system).
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.
Note that discussion about the merits or otherwise of the GPL should
be posted to gnu.misc.discuss and not to the
comp.os.linux groups.
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