Archive-name: linux-faq/info-sheetăLast-modified: 19 Mar 93ăVersion: 3.00ăă Linux Information Sheet ăăă 0.1 Introduction to Linux ăă Linux runs only on 386/486 machines with an ISA or EISA bus. MCA ă (IBM's proprietary bus) is not currently supported because there ă is little available documentation. However, support for MCA is ă being added at this time. Porting to other architectures is ă likely to be difficult, as the kernel makes extensive use of 386 ă memory management and task primitives. However, despite these ă difficulties, there are people successfully working on a port to ă the Amiga. ăă Linux is still considered to be in beta testing. There are still ă bugs in the system, and since Linux develops rapidly (new ă versions come out about once every two weeks), new bugs creep ă up. However, these bugs are fixed quickly as well. Many versions ă are quite stable, and you can keep using those if they do what ă you need and you don't want to be on the bleeding edge. Some ă sites have been running Linux systems continuously doing real ă work for more than 50 days, without a single reboot, crash, or ă error message. Note that this figure was collected with a ă version of Linux that dates from last June: Linux has become ă significantly better since then. ăă One thing to be aware of is that Linux is developed using an ă open and distributed model, instead of a closed and centralized ă model like much other software. This means that the current ă development version is always public (with up to a week or two's ă delay) so that anybody can use it. The result is that whenever a ă version with new functionality is released, it almost always ă contains bugs, but it also results in a very rapid development ă so that the bugs are found and corrected quickly, often in ă hours, as many people work to fix them. Furthermore, the bugs ă are generally discovered within hours of a kernel release, ă especially those which might endanger a user's data, so it is ă easy for an end-user to avoid these bugs. ăă In contrast, the closed and centralized model means that there ă is only one person or team working on the project, and they only ă release software that they think is working well. Often this ă leads to long intervals between releases, long waiting for bug ă fixes, and slower development. Of course, the latest release of ă such software to the public is often of higher quality, but the ă development speed is generally much slower. ăă As of March 17, 1993, the current version of Linux is 0.99 ă patchlevel 7. ăăă 0.2 Linux Features ăăă * multitasking: several programs running at once. ăă * multiuser: several users on the same machine at once (and NO ă two-user licenses!). ăă * runs in 386 protected mode. ăă * has memory protection between processes, so that one program ă can't bring the whole system down. ăă * demand loads executables: Linux only reads from disk those ă parts of a program that are actually used. ăă * shared copy-on-write pages among executables. ăă * virtual memory using paging (not swapping whole processes) to ă disk: to a separate partition or a file in the filesystem, or ă both, with the possibility of adding more swapping areas ă during runtime (yes, they're still called swapping areas). A ă total of 16 of these 16 MB swapping areas can be used at ă once, for a total 256 MB of useable swap space. ăă * a unified memory pool for user programs and disk cache (so ă that all free memory can be used for caching, and the cache ă can be reduced when running large programs). ăă * dynamically linked shared libraries (DLL's)(static libraries ă too, of course). ăă * does core dumps for post-mortem analysis (using a debugger on ă a program after it has crashed). ăă * mostly compatible with POSIX, System V, and BSD at the source ă level. ăă * all source code is available, including the whole kernel and ă all drivers, the development tools and all user programs; ă also, all of it is freely distributable. ăă * POSIX job control. ăă * pseudoterminals (pty's). ăă * 387-emulation in the kernel so that programs don't need to do ă their own math emulation. Every computer running Linux ă appears to have a math coprocessor. ăă * support for many national or customized keyboards, and it is ă fairly easy to add new ones. ăă * multiple virtual consoles: several independent login sessions ă through the console, you switch by pressing a hot-key ă combination (not dependent on video hardware). ăă * Supports several common filesystems, including minix-1 and ă Xenix, and has an advanced filesystem of its own, which ă offers filesystems of up to 4 TB, and names up to 255 ă characters long. ăă * transparent access to MS-DOS partitions (or OS/2 FAT ă partitions) via a special filesystem: you don't need any ă special commands to use the MS-DOS partition, it looks just ă like a normal Unix filesystem (except for funny restrictions ă on filenames, permissions, and so on). ăă * CD-ROM filesystem which reads all standard formats of ă CD-ROMs. ăă * TCP/IP networking, including ftp, telnet, NFS, etc. ăăă 0.3 Hardware Issues ăăă 0.3.1 Minimal configuration ăă The following is probably the smallest possible configuration ă that Linux will work on: 386SX/16, 2 MB RAM, 1.44 MB or 1.2 MB ă floppy, any supported video card (+ keyboards, monitors, and so ă on of course). This should allow you to boot and test whether it ă works at all on the machine, but you won't be able to do ă anything useful. ăă In order to do something, you will want some hard disk space as ă well, 5 to 10 MB should suffice for a very minimal setup (with ă only the most important commands and perhaps one or two small ă applications installed, like, say, a terminal program). This is ă still very, very limited, and very uncomfortable, as it doesn't ă leave enough room to do just about anything, unless your ă applications are quite limited. It's generally not recommended ă for anything but testing if things work, and of course to be ă able to brag about small resource requirements. ăăă 0.3.2 Usable configuration ăă If you are going to run computationally intensive programs, such ă as gcc, X, and TeX, you will probably want a faster processor ă than a 386SX/16, but even that should suffice if you are ă patient. ăă In practice, you need at least 4 MB of RAM if you don't use X, ă and 8 MB if you do. Also, if you want to have several users at a ă time, or run several large programs (compilations for example) ă at a time, you may want more than 4 MB of memory. It will still ă work with a smaller amount of memory (should work even with 2 ă MB), but it will use virtual memory (using the hard drive as ă slow memory) and that will be so slow as to be unusable. ăă The amount of hard disk you need depends on what software you ă want to install. The normal basic set of Unix utilities, shells, ă and administrative programs should be comfortable in less than ă 10 MB, with a bit of room to spare for user files. For a more ă complete system, the SLS documentation reports that a full base ă system without X fits into 20 MB, and with X into 40 MB (this is ă only binaries). Add the whatever space you want to reserve for ă user files. ăă Add more memory, more hard disk, a faster processor and other ă stuff depending on your needs, wishes and budget to go beyond ă the merely usable. In general, one big difference from DOS is ă that with Linux, adding memory makes a large difference, whereas ă with dos, extra memory doesn't make that much difference. This ă of course has something to do with DOS's 640KB limit. ăăă 0.3.3 Supported hardware ăă CPU: Anything that runs 386 protected mode programs (all models ă of 386s and 486s should work; 286s don't work, and never will). ăă Architecture: ISA or EISA bus (you still need an ISA-bus hard ă disk controller, though). MCA (aka PS/2) does not work. Local ă bus works. ăă RAM: Theoretically up to 1 GB, but using more than 16 MB ă requires that the kernel be recompiled. ăă Data storage: Generic AT drives (IDE, 16 bit HD controllers with ă MFM or RLL) are supported, as are SCSI hard disks and CD-ROMs, ă with a supported SCSI adaptor. Generic XT controllers (8 bit ă controllers with MFM or RLL) need a special driver which is not ă currently part of the standard kernel. Supported SCSI adaptors: ă Adaptec 1542 (but not 1522), 1740 in extended (not 1542 ă compatible) mode, Seagate ST-01 and ST-02, Future Domain TMC-88x ă series (or any board based on the TMC950 chip) and TMC1660/1680, ă Ultrastor 14F, and Western Digital wd7000. SCSI and QIC-02 tapes ă are also supported. ăă Video: VGA, EGA, CGA, or Hercules (and compatibles) work in text ă mode. For graphics and X, there is support for (at least) EGA, ă normal VGA, some super-VGA cards (most of the cards based on ă ET3000, ET4000, Paradise, and some Trident chipsets), some S3 ă cards (not Diamond Stealth, because the manufacturer won't tell ă how to program it), 8514/A, and hercules. (Linux uses the ă Xfree86 X server, so that determines what cards are supported.) ăă Other hardware: SoundBlaster, AST Fourport cards (with 4 serial ă boards), several flavours of bus mice (Microsoft, Logitech, ă PS/2). ăăă 0.4 An Incomplete List of Ported Programs and Other Software ăăă Most of the common Unix tools and programs have been ported to ă Linux, including almost all of the GNU stuff and many X clients ă from various sources. Actually, ported is often too strong a ă word, since many programs compile out of the box without ă modifications, or only small modifications, because Linux tracks ă POSIX quite closely. Unfortunately, there are not very many ă end-user applications at this time. Nevertheless, here is an ă incomplete list of software that is known to work under Linux. ăă Basic Unix commands: ls, tr, sed, awk and so on (you name it, ă we've probably got it). ăă Development tools: gcc, gdb, make, bison, flex, perl, rcs, cvs, ă gprof. ăă Graphical environments: X11R5 (Xfree86), MGR. ăă Editors: GNU Emacs, Lucid Emacs, MicroEmacs, jove, epoch, elvis, ă joe, pico. ăă Shells: Bash, zsh (include ksh compatiblity mode), tcsh, csh, ă rc, ash. ăă Telecommunication: Taylor (BNU-compatible) UUCP, kermit, szrz, ă minicom, pcomm, xcomm, term/slap (runs multiple shells over one ă modem line), and Seyon. ăă News and mail: C-news, trn, nn, tin, smail, elm, mh. ăă Textprocessing: TeX, groff, doc. ăă Games: Nethack, several Muds and X games. ăă All of these programs (and this isn't even a hundredth of what ă is available) are freely available. ăăă 0.5 Getting Linux ăăăă 0.5.4 Anonymous FTP ăă At least the following anonymous ftp sites carry Linux. This ă list is taken from the Meta-FAQ list, which is posted every week ă to the comp.os.linux newsgroup (the Meta-FAQ is updated more ă often than this information sheet, so the list below may not be ă the most current one). ăăăă Textual name Numeric address Linux directoryă ============================= =============== ===============ă tsx-11.mit.edu 18.172.1.2 /pub/linuxă sunsite.unc.edu 152.2.22.81 /pub/Linuxă nic.funet.fi 128.214.6.100 /pub/OS/Linuxă ftp.mcc.ac.uk 130.88.200.7 /pub/linuxă fgb1.fgb.mw.tu-muenchen.de 129.187.200.1 /pub/linuxă ftp.informatik.tu-muenchen.de 131.159.0.110 /pub/Linuxă ftp.dfv.rwth-aachen.de 137.226.4.105 /pub/linuxă ftp.informatik.rwth-aachen.de 137.226.112.172 /pub/Linuxă ftp.ibp.fr 132.227.60.2 /pub/linuxă kirk.bu.oz.au 131.244.1.1 /pub/OS/Linuxă ftp.uu.net 137.39.1.9 /packages/linuxă wuarchive.wustl.edu 128.252.135.4 mirrors/linuxă ftp.win.tue.nl 131.155.70.100 /pub/linuxă ftp.stack.urc.tue.nl 131.155.2.71 /pub/linuxă srawgw.sra.co.jp /Linuxă ftp.ibr.cs.tu-bs.de 134.169.34.15 /pub/os/linuxă cair.kaist.ac.kr /pub/Linuxă ftp.denet.dk 129.142.6.74 /pub/OS/linuxăăăă tsx-11.mit.edu and fgb1.fgb.mw.tu-muenchen.de are the official ă sites for Linux' GCC. Some sites mirror other sites. Please use ă the site closest (network-wise) to you whenever possible. ăăă 0.5.5 Other methods of obtaining Linux ăă There are several BBS's that have Linux files. A list of them is ă maintained by Zane Healy; he posts it to the comp.os.linux ă newsgroup around the beginning and middle of the month, please ă see that post for more information. comp.os.linux is echoed on ă the LINUX echoid on fidonet. ăă There is also at least one organization that distributes Linux ă on floppies, for a fee. Contact ăăă Softlanding Softwareă 910 Lodge Ave.ă Victoria, B.C., Canadaă V8X-3A8ă +1 608 360 0188ăă for information on purchasing. There is also an organization ă which sells Linux on CD-ROM --- contact ăăă Yggdrasil Computing, Incorporatedă CDROM salesă PO Box 8418ă 94707--8418ă 510--526--7531ăă for information on purchasing the CD-ROM. Also, don't forget ă about friends and user's groups, who are usually glad to let you ă make a copy. ăăă 0.5.6 Getting started ăă As mentioned at the beginning, Linux is not centrally ă administered. Because of this, there is no ``official'' release ă that one could point at, and say ``That's Linux.'' Instead, ă there are various ``distributions,'' which are more or less ă complete collections of software configured and packaged so that ă they can be used to install a Linux system. The most important ă one is currently the SLS release. ăă SLS is put together by Peter MacDonald, and is the more ă full-featured one. It contains much of the available software, ă and includes X. I really recommend SLS to anyone who's serious ă about getting started with Linux. ăă The first thing you should do is to get and read the list of ă Frequently Asked Questions (FAQ) from one of the FTP sites, or ă by using the normal Usenet FAQ archives (e.g. ă pit-manager.mit.edu). This document has plenty of instructions ă on what to do to get started, what files you need, and how to ă solve most of the common problems (during installation or ă otherwise). ăăă 0.6 Legal Status of Linux ăăă Although Linux is supplied with the complete source code, it is ă copyrighted software, not public domain. However, it is ă available for free under the GNU Public License. See the GPL for ă more information. The programs that run under Linux have each ă their own copyright, although much of it uses the GPL as well. ă All of the software on the FTP site is freely distributable (or ă else it shouldn't be there). ăăă 0.7 News About Linux ăăă There is a Usenet newsgroup, comp.os.linux, for Linux ă discussion, and also several mailing lists. See the Linux FAQ ă for more information about the mailing lists (you should be able ă to find the FAQ either in the newsgroup or on the FTP sites). ăă The newsgroup comp.os.linux.announce is a moderated newsgroup ă for announcements about Linux (new programs, bug fixes, etc). ăă For the current status of the Linux kernel and a summary of the ă most recent versions, finger torvalds@kruuna.helsinki.fi ăă There is also a more or less weekly ``newsletter,'' Linux News, ă which summarizes the most important announcements and uploads, ă and has occasional other articles as well. Look in ă comp.os.linux.announce for a sample issue. ăăă 0.8 Future Plans ăăă Work is underway on Linux version 1.0, which will close some of ă the gaps in the present implementation. The major functionality ă shortcomings are advanced interprocess communication ă (semaphores, shared memory), closer compatibility with POSIX, ă and a lot of tweaking. Documentation is also sorely missing, but ă is being worked on by those on the ``Linux Documentation ă Project'' (the DOC channel of the linux-activists@niksula.hut.fi ă mailing list). By April 1993 there should be a complete ă installation and getting started manual for Linux. ăăă 0.9 This document ăăă This document is maintained by Michael K. Johnson, ă johnsonm@stolaf.edu. Please mail me with any comments. A current ă copy of this document can always be found as ă tsx-11.mit.edu:/pub/linux/docs/INFO-SHEET, and a .dvi version ă can be found as INFO-SHEET.dvi, in the same directory. ăăă 0.10 Legalese ăăă Trademarks are owned by their owners. There is no warranty about ă the information in this document. ă