ch01.htm

linux-unix130.linux.and.unix.ebooks130 linux and unix ebookslinuxLearning Linux - Collection of 12 E

such support, however, the assumption is that the software comes with no such warranty.

If you use a piece of software that is covered by the GPL, and that software goes

haywire and wipes out everything on your system, neither the authors nor those who

distributed the software to you are liable for any damage under any circumstances.</P>

<P>An item as covered by the GPL is not shareware, nor is it in the public domain.

Neither of these two terms correctly describes what free software really is. The

complete GNU GPL is included in Appendix E. To sum it all up, you can freely distribute

Linux as much as you like, and you can even modify, copy, sell, and distribute your

own version of Linux (and its associated files). But, in doing so, you can't take

away any rights of others who want to copy and distribute it further, even if for

money. This also applies to the HOWTO documents on the CD-ROM with this book. If

you distribute any document, you must do so in its entirety (as it is found on the

CD-ROM at the back of the book). The original authors of all Linux software and documentation

will always hold copyrights to what they have done.



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	<DD>

<HR>

<A NAME="Heading14<FONT COLOR="#000077"><B>CAUTION: </B></FONT>Note that there

	are absolutely no warranties with any of the software you get with Linux. If an application

	goes awry and wipes out your disk, you have no one's neck to wring. Unless someone

	explicitly gives you a warranty in writing for the software, do not assume any warranty

	whatsoever.

<HR>



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<H3 ALIGN="CENTER"><A NAME="Heading15<FONT COLOR="#000077">Hardware Requirements</FONT></H3>

<P>Now that you know a little about the good and bad points of Linux, let's see what's

required in terms of hardware. Keep the following statement in mind:





<BLOCKQUOTE>

	<P>There are no guarantees that the version of Linux on the CD-ROM at the back of

	the book, or any free Linux version for that matter, will work with your system.



</BLOCKQUOTE>



<P>Due to the popularity of Linux, many hardware vendors can provide support for

using their cards with Linux. Ask the manufacturers for help with Linux drivers,

and ask whether they support X Window under Linux. &quot;No-name&quot; or generic

hardware compatibility in Linux is still limited to the hardware that the developers

themselves have access to. For instance, if none of the Linux developers has access

to the WhizBang Slice-O-Matic T3222 Ethernet card from a no-name manufacturer, chances

are that it isn't supported. Few Linux developers are motivated to support hardware

that is not common.</P>

<P>Unlike some other versions of UNIX for the PC, Linux is very small. You can run

an entire system from a single high-density 5[dieresis]-inch floppy. To run a complete

Linux system, however, there are other hardware requirements. For example, you need

device drivers to be able to use certain types of devices under Linux. Fortunately,

there are many generic drivers for the IDE disk driver for Linux. These generic drivers

should work with all IDE hard drives and adapters. Most internal tape drives are

supported, but external tape drives that run off the parallel printer port are generally

not supported.</P>

<P>A good place to look on the CD-ROM is in the <TT>/docs</TT> directory for the

<TT>Hardware-HOWTO</TT> file. This file lists many of the supported hardware devices

for Linux.</P>

<P>If your favorite peripheral isn't supported by Linux, all that's required is to

write a kernel driver for it. This might be easy or difficult, depending on the hardware

and the technical specifications that are available. For example, some hardware developers

prefer to write their own drivers for MS-DOS and Windows, and not release specifications

for third parties to write their own. Therefore, writing drivers for Linux can be

difficult, if not impossible.</P>

<P>If after trying four or five different kernels, your CD-ROM, Ethernet card, or

sound card does not work, look in the <TT>Hardware-HOWTO</TT> file to see whether

your hardware is even supported. If your hardware is not listed, it might not be

supported. Easiest solution: Get new hardware that is supported. Search the Internet

for drivers. Do not try to jury-rig whatever software comes with the CD-ROM unless

you know UNIX well enough to write your own drivers. For example, if your Phillips

CD-ROM drive is not supported (it probably isn't), get another CD-ROM drive from

the list in the <TT>Hardware-HOWTO</TT>. It's bound to save you time and prevent

frustration in the future.</P>

<P>The best approach, in the case of incompatibility, is to stay with the most commonly

used hardware and hope for the best. Chances are greater for your system to work

with Linux. Plus, you will find yourself with more time to play with Linux!</P>

<P>The following bulleted list is a rough guideline of some hardware requirements

for Linux. You do not have to follow the guidelines exactly, but this list should

give you a general idea of what is required.



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	<DD>

<HR>

<A NAME="Heading16<FONT COLOR="#000077"><B>TIP: </B></FONT>If you're in the

	market for a new system, you should heed the following recommendations.

<HR>



</DL>





<UL>

	<LI>You need an Intel 80386, 80486, or Pentium-based system. You don't need a math

	coprocessor, although I strongly recommend that you have one. A Pentium processor

	will be the best choice for the future. For those with an 80386 chip, 80387 math

	coprocessors are available separately and are installed in a socket on your motherboard.

	For those with an 80486 processor, the math coprocessor is on the 486 chip itself.

	(The exception is the 80486SX, which is a 486 chip with the coprocessor disabled.)

</UL>





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	<DD>If you don't have a math coprocessor, the Linux kernel emulates floating-point

	math for you. If you do have one, however, floating-point math is handled by the

	hardware, which is a real plus in speed for some applications.<BR>

	The 386SX, the 486SX, the accelerated 486DX and 486DX2, and other clone chips are

	all reported to work without any problems.

</DL>





<UL>

	<LI>Users of DEC Alpha, Motorola processor-based systems, and Macintosh should check

	the FTP site <TT>sunsite.unc.edu</TT> for versions that reflect their own hardware.

	The DEC Alpha version is perhaps the most stable version of Linux at this time. In

	general, be prepared to work with slightly older versions of Linux if you are not

	on an Intel platform.

	<P>

	<LI>Your system must be an ISA, EISA, or PCI architecture machine. These terms specify

	how the CPU communicates with hardware and are a characteristic of your motherboard.

	Most existing systems use the ISA bus architecture. Pentiums with PCI bus video cards

	do not pose any problems either. PCI architecture is often the fastest of the three,

	because it allows the CPU to communicate directly to video and drive adapters.

</UL>





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	<DD>

<HR>

<A NAME="Heading17<FONT COLOR="#000077"><B>NOTE: </B></FONT>MicroChannel architecture

	(MCA) machines, such as the IBM PS/2 line, are still not supported.

<HR>



</DL>





<UL>

	<LI>A minimum of 4MB of RAM is required to run Linux. Do not attempt to run Linux

	on any less memory.

</UL>





<DL>

	<DD>Memory is speed, so if you have more physical RAM, you'll thank yourself for

	it later. If you're a &quot;power user,&quot; 8MB should be more than enough for

	most applications. More than 8MB of RAM definitely speeds up some applications. In

	fact, if you want to use X Window with any hope of getting some work done, install

	at least 8MB of RAM.

	<DT></DT>

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	<DD>

<HR>

<A NAME="Heading18<FONT COLOR="#000077"><B>NOTE: </B></FONT>Linux uses the

	first 640KB for kernel text, data, and buffer caches. Your motherboard might also

	use up an additional 384KB because of the chip set. While Linux is running, it uses

	up memory for processes such as init/login, a shell, and possibly other background

	processes. Compiling programs takes up more memory in the system. Such requests for

	extra memory are satisfied by paging from a swap file on disk. A disk is much slower

	than memory. So if you don't have enough real memory, you have to resort to paging

	contents of memory to and from disk.

<HR>



</DL>





<UL>

	<LI>An AT standard-compatible hard-drive controller is required. This includes MFM,

	RLL, ESDI, and IDE controllers. Many SCSI controllers are also supported. These terms

	specify the means used to communicate with the hard drive through the controller

	card; most controllers are either IDE or SCSI.

</UL>



<H4 ALIGN="CENTER"><A NAME="Heading19<FONT COLOR="#000077">Disk Space Requirements</FONT></H4>

<P>You need a hard drive with adequate space available for installing Linux. The

amount of space required depends on the amount of software you're installing and

how much free space you want to leave yourself to store your own data and programs.</P>

<P>If you install only a small amount of software, about 10MB is required. If, however,

you install some optional software packages, including the X Window System, perhaps

100MB or more (including space for users) is required.</P>

<P>In addition, you probably want to set aside some amount of space on your drive

as a swap partition, used for virtual memory.</P>

<P>In general, you should look for about 100MB of disk space for your use, and an

additional 16MB or so of disk space for a swap space. The swap space is an area on

the disk that is a repository in which Linux can store images of running programs

when memory is tight. Usually, the amount of swap space is twice that of physical

memory in the system. For example, if you have a 16MB system, you will probably want

to have 32MB of swap space on your system. Again, having twice the size is a rule

of thumb, nothing more.</P>

<P>Linux supports almost all hard drive/controller combinations that are register-compatible

with a Western Digital WD1003 MFM disk controller. This controller was the original

and most common PC-AT disk controller. Most AT MFM, RLL, ESDI, and IDE setups look

like this. IDE and MFM drives seem to work with no problem. Linux also works for

some ESDI drives, and for almost all SCSI devices, with no problems. As before, the

<TT>Hardware-HOWTO</TT> file lists the latest compatible hardware. The <TT>Hardware-HOWTO</TT>

file is located in the <TT>docs</TT> directory on the CD-ROM at the back of this

book.</P>

<P>Generally, the rule is this: If you have the disk configured into the CMOS setup

of your machine, it will work, because if your computer's BIOS is communicating with

a WD 1003- compatible board, Linux will too.



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