476 lines
22 KiB
Plaintext
476 lines
22 KiB
Plaintext
Linux Information Sheet
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0.1 Introduction to Linux
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Linux is a completely free reimplementation of the POSIX spec,
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with SYSV and BSD extensions (which means, it looks like unix,
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but does not come from the same source code base), which is
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available in both source code and binary form. It is copyrighted
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by Linus B. Torvalds (torvalds@kruuna.helsinki.fi) and other
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contributors and is freely redistributable under the terms of
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the GNU Public License. Linux runs only on 386/486 machines with
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an ISA or EISA bus. MCA (IBM's proprietary bus) is not currently
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supported because there is little available documentation. Some
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people have started support for PCI, but it is currently not
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ready for the standard distribution on Linux.
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Porting to other CPU's is likely to be difficult, as the kernel
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makes extensive use of 386 memory management and task
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primitives. However, this is becoming easier as the kernel
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becomes more general, and there is a port in progress for
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multiple Motorola 680x0 platforms, and ports are being
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considered to other platforms as well. Don't hold your breath,
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but if you are interested and able to contribute, you may find
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other developers who wish to work with you.
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Linux is still considered to be in beta testing. There are still
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bugs in the system, and since Linux develops rapidly (new
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versions come out about once every two weeks), new bugs creep
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up. However, these bugs are fixed quickly as well. Most versions
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are quite stable, and you can keep using those if they do what
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you need and you don't want to be on the bleeding edge. One site
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has had a computer running version 0.97 patchlevel 1 (dating
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from last summer) for over 136 days without an error or crash.
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(It would have been longer if the backhoe operator hadn't
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mistaken a main power transformer for a dumpster...)
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One thing to be aware of is that Linux is developed using an
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open and distributed model, instead of a closed and centralized
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model like much other software. This means that the current
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development version is always public (with up to a week or two's
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delay) so that anybody can use it. The result is that whenever a
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version with new functionality is released, it almost always
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contains bugs, but it also results in a very rapid development
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so that the bugs are found and corrected quickly, often in
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hours, as many people work to fix them. Furthermore, the bugs
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are generally discovered within hours of a kernel release,
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especially those which might endanger a user's data, so it is
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easy for an end-user to avoid these bugs.
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In contrast, the closed and centralized model means that there
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is only one person or team working on the project, and they only
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release software that they think is working well. Often this
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leads to long intervals between releases, long waiting for bug
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fixes, and slower development. Of course, the latest release of
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such software to the public is often of higher quality, but the
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development speed is generally much slower.
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As of October 25, 1993, the current version of Linux is 0.99
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patchlevel 13.
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0.2 Linux Features
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* multitasking: several programs running at once.
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* multiuser: several users on the same machine at once (and NO
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two-user licenses!).
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* runs in 386 protected mode.
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* has memory protection between processes, so that one program
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can't bring the whole system down.
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* demand loads executables: Linux only reads from disk those
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parts of a program that are actually used.
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* shared copy-on-write pages among executables. This means that
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multiple process can use the same memory to run in. When one
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tries to write to that memory, that page (4KB piece of
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memory) is copied somewhere else. Copy-on-write has two
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benefits: increasing speed and decreasing memory use.
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* virtual memory using paging (not swapping whole processes) to
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disk: to a separate partition or a file in the filesystem, or
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both, with the possibility of adding more swapping areas
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during runtime (yes, they're still called swapping areas). A
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total of 16 of these 16 MB swapping areas can be used at
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once, for a total 256 MB of useable swap space.
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* a unified memory pool for user programs and disk cache (so
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that all free memory can be used for caching, and the cache
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can be reduced when running large programs).
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* dynamically linked shared libraries (DLL's)(static libraries
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too, of course).
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* does core dumps for post-mortem analysis, allowing the use of
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a debugger on a program not only while it is running but also
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after it has crashed.
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* mostly compatible with POSIX, System V, and BSD at the source
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level.
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* all source code is available, including the whole kernel and
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all drivers, the development tools and all user programs;
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also, all of it is freely distributable.
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* POSIX job control.
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* pseudoterminals (pty's).
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* 387-emulation in the kernel so that programs don't need to do
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their own math emulation. Every computer running Linux
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appears to have a math coprocessor. Of course, if your
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computer already contains an FPU, it will be used instead of
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the emulation, and you can even compile your own kernel with
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math emulation removed, for a small memory gain.
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* support for many national or customized keyboards, and it is
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fairly easy to add new ones.
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* multiple virtual consoles: several independent login sessions
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through the console, you switch by pressing a hot-key
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combination (not dependent on video hardware).
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* Supports several common filesystems, including minix-1 and
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Xenix, and has an advanced filesystem of its own, which
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offers filesystems of up to 4 TB, and names up to 255
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characters long.
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* transparent access to MS-DOS partitions (or OS/2 FAT
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partitions) via a special filesystem: you don't need any
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special commands to use the MS-DOS partition, it looks just
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like a normal Unix filesystem (except for funny restrictions
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on filenames, permissions, and so on). MS-DOS 6 compressed
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partitions do not work at this time.
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* CD-ROM filesystem which reads all standard formats of
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CD-ROMs.
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* TCP/IP networking, including ftp, telnet, NFS, etc.
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0.3 Hardware Issues
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0.3.1 Minimal configuration
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The following is probably the smallest possible configuration
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that Linux will work on: 386SX/16, 2 MB RAM, 1.44 MB or 1.2 MB
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floppy, any supported video card (+ keyboards, monitors, and so
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on of course). This should allow you to boot and test whether it
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works at all on the machine, but you won't be able to do
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anything useful.
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In order to do something, you will want some hard disk space as
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well, 5 to 10 MB should suffice for a very minimal setup (with
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only the most important commands and perhaps one or two small
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applications installed, like, say, a terminal program). This is
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still very, very limited, and very uncomfortable, as it doesn't
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leave enough room to do just about anything, unless your
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applications are quite limited. It's generally not recommended
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for anything but testing if things work, and of course to be
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able to brag about small resource requirements.
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0.3.2 Usable configuration
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If you are going to run computationally intensive programs, such
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as gcc, X, and TeX, you will probably want a faster processor
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than a 386SX/16, but even that should suffice if you are
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patient.
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In practice, you need at least 4 MB of RAM if you don't use X,
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and 8 MB if you do. Also, if you want to have several users at a
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time, or run several large programs (compilations for example)
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at a time, you may want more than 4 MB of memory. It will still
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work with a smaller amount of memory (should work even with 2
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MB), but it will use virtual memory (using the hard drive as
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slow memory) and that will be so slow as to be unusable.
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The amount of hard disk you need depends on what software you
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want to install. The normal basic set of Unix utilities, shells,
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and administrative programs should be comfortable in less than
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10 MB, with a bit of room to spare for user files. For a more
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complete system, SLS reports that a full base system without X
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fits into 45 MB, with X into 70 MB (this is only binaries), and
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a complete distribution with everything takes 90 MB. MCC
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provides a much sparser, smaller, and perhaps cleaner
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installation. Add the whatever space you want to reserve for
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user files to these totals. With today's prices on hard drives,
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if you are buying a new system, it makes no sense to buy a drive
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that is too small. Get at least 200 MB, and you will not regret
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it.
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Add more memory, more hard disk, a faster processor and other
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stuff depending on your needs, wishes and budget to go beyond
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the merely usable. In general, one big difference from DOS is
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that with Linux, adding memory makes a large difference, whereas
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with dos, extra memory doesn't make that much difference. This
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of course has something to do with DOS's 640KB limit.
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0.3.3 Supported hardware
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CPU: Anything that runs 386 protected mode programs (all models
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of 386s and 486s should work; 286s don't work, and never will).
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Architecture: ISA or EISA bus. MCA (mostly true blue PS/2's)
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does not work. Local bus works.
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RAM: Theoretically up to 1 GB. This has not been tested. Some
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people (including Linus) have noted that adding ram has slowed
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down their machine extremely without adding more cache at the
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same time, so if you add memory and find your machine slower,
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try adding more cache.
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Data storage: Generic AT drives (IDE, 16 bit HD controllers with
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MFM or RLL) are supported, as are SCSI hard disks and CD-ROMs,
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with a supported SCSI adaptor. Generic XT controllers (8 bit
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controllers with MFM or RLL) are now also supported. Supported
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SCSI adaptors: Adaptec 1542, 1522, and 1740 in extended (not
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1542 compatible) mode, Seagate ST-01 and ST-02, Future Domain
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TMC-88x series (or any board based on the TMC950 chip) and
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TMC1660/1680, Ultrastor 14F, 24F and 34F, and Western Digital
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wd7000. SCSI and QIC-02 tapes are also supported. Support for
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QIC-80 tapes is now in ALPHA testing.
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Video: VGA, EGA, CGA, or Hercules (and compatibles) work in text
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mode. For graphics and X, there is support for (at least) normal
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VGA, some super-VGA cards (most of the cards based on ET3000,
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ET4000, Paradise, and some Trident chipsets), some S3 cards (not
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Diamond Stealth, because the manufacturer won't tell how to
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program it), 8514/A, and hercules. (Linux uses the Xfree86 X
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server, so that determines what cards are supported.)
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Networking: Western Digital 80x3, ne1000, ne2000, 3com503,
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3com509, Allied Telliesis AT1500 (said to be some of the
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fastest, as well as quite cheap), d-link pocket adaptors, SLIP,
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CSLIP, PLIP (Parallel Link IP), and more I have forgotten at the
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moment.
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Other hardware: SoundBlaster, ProAudio Spectrum 16, Gravis
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Ultrasound, AST Fourport cards (with 4 serial ports), several
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models of Boca serial boards, the Usenet Serial Card II, several
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flavours of bus mice (Microsoft, Logitech, PS/2).
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0.4 An Incomplete List of Ported Programs and Other Software
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Most of the common Unix tools and programs have been ported to
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Linux, including almost all of the GNU stuff and many X clients
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from various sources. Actually, ported is often too strong a
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word, since many programs compile out of the box without
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modifications, or only small modifications, because Linux tracks
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POSIX quite closely. Unfortunately, there are not very many
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end-user applications at this time. Nevertheless, here is an
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incomplete list of software that is known to work under Linux.
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Basic Unix commands: ls, tr, sed, awk and so on (you name it,
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we've probably got it).
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Development tools: gcc, gdb, make, bison, flex, perl, rcs, cvs,
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gprof.
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Graphical environments: X11R5 (Xfree86), MGR.
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Editors: GNU Emacs, Lucid Emacs, MicroEmacs, jove, epoch, elvis,
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joe, pico, jed.
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Shells: Bash (POSIX sh-compatible), zsh (include ksh
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compatiblity mode), pdksh, tcsh, csh, rc, ash (mostly
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sh-compatible), and many more.
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Telecommunication: Taylor (BNU-compatible) UUCP, kermit, szrz,
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minicom, pcomm, xcomm, term/slap (runs multiple shells over one
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modem line), and Seyon.
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News and mail: C-news, trn, nn, tin, smail, elm, mh.
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Textprocessing: TeX, groff, doc.
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Games: Nethack, several Muds and X games.
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All of these programs (and this isn't even a hundredth of what
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is available) are freely available.
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0.5 Who uses Linux?
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Linux is freely available, and no one is required to register
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their copies with any central authority, so it is difficult to
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know how many people use Linux. Several businesses are now
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surviving solely on selling and supporting Linux, and very few
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Linux users use those businesses, relatively speaking, and the
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Linux newsgroups are some of the most heavily read on the
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internet, so the number is likely in the hundreds of thousands,
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but hard numbers are hard to come by. However, one brave soul,
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Harald T. Alvestrand, has decided to try, and asks that if you
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use Linux, you send a message to linux-counter@uninett.no with
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one of the following subjects: ``I use Linux at home'', ``I use
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Linux at work'', or ``I use Linux at home and at work''. He is
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also counting votes of ``I don't use Linux'', for some reason.
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He posts his counts to comp.os.linux.misc.
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0.6 Getting Linux
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0.6.4 Anonymous FTP
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New information: Matt Welsh has written a 150 page guide on
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getting, installing, and setting up Linux. It is available from
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tsx-11.mit.edu:/pub/linux/docs/LDP/install*, and is available as
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LaTeX source as well as DVI, PostScript, and text files. It is
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also sold by some people in hard copy, and may be published as a
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book soon. Also, the Linux documentation project (the LDP) has
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put out several other books in various states of completion, and
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these are available at sunsite.unc.edu:/pub/Linux/docs/LDP. Stay
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tuned to comp.os.linux.announce.
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At least the following anonymous ftp sites carry Linux.
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Textual name Numeric address Linux directory
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============================= =============== ===============
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tsx-11.mit.edu 18.172.1.2 /pub/linux
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sunsite.unc.edu 152.2.22.81 /pub/Linux
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nic.funet.fi 128.214.6.100 /pub/OS/Linux
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ftp.mcc.ac.uk 130.88.203.12 /pub/linux
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src.doc.ic.ac.uk 146.169.2.1 /packages/linux
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fgb1.fgb.mw.tu-muenchen.de 129.187.200.1 /pub/linux
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ftp.informatik.tu-muenchen.de 131.159.0.110 /pub/Linux
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ftp.dfv.rwth-aachen.de 137.226.4.105 /pub/linux
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ftp.informatik.rwth-aachen.de 137.226.112.172 /pub/Linux
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ftp.ibp.fr 132.227.60.2 /pub/linux
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kirk.bond.edu.au 131.244.1.1 /pub/OS/Linux
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ftp.uu.net 137.39.1.9 /systems/unix/linux
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wuarchive.wustl.edu 128.252.135.4 mirrors/linux
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ftp.win.tue.nl 131.155.70.100 /pub/linux
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ftp.stack.urc.tue.nl 131.155.2.71 /pub/linux
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srawgw.sra.co.jp /Linux
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ftp.ibr.cs.tu-bs.de 134.169.34.15 /pub/os/linux
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cair.kaist.ac.kr /pub/Linux
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ftp.denet.dk 129.142.6.74 /pub/OS/linux
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tsx-11.mit.edu and fgb1.fgb.mw.tu-muenchen.de are the official
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sites for Linux' GCC. Some sites mirror other sites. Please use
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the site closest (network-wise) to you whenever possible.
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If you are lost, try looking at
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SunSite.unc.edu:/pub/Linux/distributions/, where several
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distributions are offered.
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0.6.5 Other methods of obtaining Linux
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There are many BBS's that have Linux files. A list of them is
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occasionally posted to comp.os.linux.announce. Ask friends and
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user groups, or order one of the commmercial distributions. A
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list of these is contained in the Linux distribution HOWTO,
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available as
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sunsite.unc.edu:/pub/Linux/docs/HOWTO/distribution-HOWTO, and
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posted regularily to the comp.os.linux.announce newsgroup.
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0.6.6 Getting started
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As mentioned at the beginning, Linux is not centrally
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administered. Because of this, there is no ``official'' release
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that one could point at, and say ``That's Linux.'' Instead,
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there are various ``distributions,'' which are more or less
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complete collections of software configured and packaged so that
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they can be used to install a Linux system.
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The first thing you should do is to get and read the list of
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Frequently Asked Questions (FAQ) from one of the FTP sites, or
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by using the normal Usenet FAQ archives (e.g. rtfm.mit.edu).
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This document has plenty of instructions on what to do to get
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started, what files you need, and how to solve most of the
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common problems (during installation or otherwise).
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0.7 Legal Status of Linux
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Although Linux is supplied with the complete source code, it is
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copyrighted software, not public domain. However, it is
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available for free under the GNU Public License. See the GPL for
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more information. The programs that run under Linux each have
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their own copyright, although many of them use the GPL as well.
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X uses the MIT X copyright, and some utilities are under the BSD
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copyright. In any case, all of the software on the FTP site is
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freely distributable (or else it shouldn't be there).
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0.8 News About Linux
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There are several Usenet newsgroups for Linux discussion, and
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also several mailing lists. See the Linux FAQ for more
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information about the mailing lists (you should be able to find
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the FAQ either in the newsgroup or on the FTP sites).
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The newsgroup comp.os.linux.announce is a moderated newsgroup
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for announcements about Linux (new programs, bug fixes, etc).
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The newsgroup comp.os.linux.admin is an unmoderated newsgroup
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for discussion of administration of Linux systems.
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The newsgroup comp.os.linux.development is an unmoderated
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newsgroup specifically for discussion of Linux kernel
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development. The only application development questions that
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should be discussed here are those that are intimately
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associated with the kernel. All other development questions are
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probably generic UNIX development questions and should be
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directed to a comp.unix group instead.
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The newsgroup comp.os.linux.help is an unmoderated newsgroup for
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any Linux questions that don't belong anywhere else.
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The newsgroup comp.os.linux.misc is the replacement for
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comp.os.linux, and is meant for any discussion that doesn't
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belong elsewhere.
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In general, do not crosspost between the Linux newsgroups. The
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only crossposting that is appropriate is an occasional posting
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between one unmoderated group and comp.os.linux.announce. The
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whole point of splitting comp.os.linux into many groups is to
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reduce traffic in each. Those that do not follow this rule will
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be flamed without mercy...
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For the current status of the Linux kernel and a summary of the
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most recent versions, finger torvalds@kruuna.helsinki.fi
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0.9 The Future
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Work is underway on Linux version 1.0, which will close some of
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the gaps in the present implementation. Documentation is also
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sorely missing, but is being worked on by those on the ``Linux
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Documentation Project'' (the DOC channel of the
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linux-activists@niksula.hut.fi mailing list). Over 600 pages of
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documentation in book form have been released by the LDP alone,
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plus a large group of man pages. More to come! Movie at six!
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Stay tuned...
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0.10 This document
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This document is maintained by Michael K. Johnson,
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johnsonm@Sunsite.unc.edu. Please mail me with any comments, no
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matter how small. I can't do a good job of maintaining this
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document without your help. A more-or-less current copy of this
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document can always be found as
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tsx-11.mit.edu:/pub/linux/docs/INFO-SHEET, and a DVI version can
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be found as INFO-SHEET.dvi, in the same directory.
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0.11 Legalese
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Trademarks are owned by their owners. There is no warranty about
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the information in this document. Use and distribute at your own
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risk. The content of this document is in the public domain, but
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please be polite and attribute any quotes.
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