Product Description
More and more businesses are turning to Linux as a cost-effective, rock-solid solution for Internal networks and Internet connectivity. This is the first book that systematically teaches Linux system administrators the real- world skills they'll need to succeed. Coverage includes everything you need to know to manage Linux networking, file service, E-mail, security, print sharing, Web, FTP and NetNews. Learn the latest practical information on configuring hardware and peripherals, customizing the kernel, tuning Linux performance, handling upgrades, and choosing among Linux distributions. Get more productive with the book's extensive practical scripts and automation techniques. There's nothing "academic" in this comprehensive guide: every word was written by expert system administrators who work with Linux every day -- and love it!
From the Inside Flap
Introduction
Get into Linux.
This chapter is the first to get you into it. Linux is probably one of the fastest growing operating systems around. It has about 5 million worldwide users, and that number is growing each day. For something that started as an idea by a college student in Finland in 1991, that is pretty darn good.
Linux is now used everywhere there is a need for a good, robust operating system. Companies run their businesses on Linux, but many may not know it. It is used for e-mail servers, WWW servers, to provide file and printer access for Microsoft and Apple machines and even other UNIX machines.
This is a guide to give you (the reader) as much knowledge as we (the authors) have attained in our years of Linux administration. The kinds of projects that administrators have to go through are varied, but they all have a common base -- managing users, e-mail, the network, hardware, and making sure that you don't mess up anything too badly while trying to make an improvement.
Oh no! Not another Linux book
This is not just a Linux book. This is the Linux book. Anyone can write some theoretical book about the way networks should run, but how many of these authors are actually the administrators of networks? How many are stuck in the trenches, reading the cryptic man pages to “printcap” while users are complaining about their printouts? We've been there, we are there, we will be there. We enjoy it.
The proof of this exists throughout the book. While everyone else goes on about IDE drives, we personally and professionally recognize the power of the SCSI bus and use it in our systems. It's more expensive and, at times, a pain to work with, but the benefits are enormous. Anyone can tell you how a program like samba is set up, but what happens in the real world, where things aren't quite the same as they are in the manual pages?
Linux Theory
The UNIX theory is “Do it your way” . But Linux is more than a chain of hamburgers. Linux allows you to not only choose what you want on your hamburger, but what's in it, how the cow is grown, what spices you add to the mixture, and how long you cook it. Linux gives you all the same abilities that commercial UNIX packages (such as Solaris or AIX) give, plus so much more.
Is it really free?
Yes and no. The GNU Public Licence (which is how Linux is licensed) says that you can charge for a binary distribution, but the source code must be either included or available for the cost of duplication. In the days of the Internet and CD-ROMs, the cost for duplicating is low indeed.
Note that this really only covers the Linux kernel, and the GNU utilities included with most distributions. This does not prevent a company like Walnut Creek, WorkGroup Solutions, or RedHat from assembling all these programs, adding a few special ones (installation and administration scripts for example), producing a CD-ROM and charging you $30 for it. The Linux kernel and source code are there. The source code to all the other GNU utilities are either also available or pointers to the source co de exist. Thus, these companies have met their end of the GNU licence. Many of these also sponsor Linux-related events or offer free CD-ROMs to software contributors. Companies such as RedHat have a more expensive product, but they add things that may not be covered by the GPL. For example, RedHat sells a copy of their distribution for three different architectures for about $30. Or you can get a copy specifically for any of the three (Alpha, Sparc, and Intel) for about $50 and get copies of commercial software, such as MetroX, along with customer support - which the $30 version doesn't offer. Companies like Caldera take this another step further and have a f ull Linux system for Intel, complete with custom software to talk to NetWare networks, for about $100.
Why Linux?
So why would you (or your company) want to use Linux in a personal or business setting? The answer goes past the short-sighted “anti-Microsoft” response. Microsoft makes a fair product for a new user. But so does Apple. Linux gives you things that Windows 95 can only dream about:
Source code for the entire kernel
Full configurability of the operating system
Ability to turn on and off features of the system without rebooting
Full 32-bit operating system. This is 64-bit for the Alpha series processors, and by the time you read this, the Sun UltraSparc will probably also be supported and 64-bit.
Access to the 25 years of software that makes up the UNIX world. This includes compilers, web servers, editors, games, and Internet tools.
As an inexpensive web server, Linux will beat NT hands down for performance on equivalent hardware. As a network server, a Linux machine hidden in the corner of an office can handle a small workgroup or a large office with months between reboots (usually to either upgrade the kernel or add new hardware). With the emergence of Java as a truly portable language, applications such as Corel's Office For Java will bring commercial applications to Linux just as fast as applications for NT or Windows 9 5. Many commercial applications (Netscape, Word Perfect, Applix, Motif, Flagship) are already available for Linux, with more being added.
Is Linux SYSV or BSD?
The simple answer to this is “Yes” . Linux takes the best of SYSV (like startup files) and the best of BSD (ps aux, getty) and combines it together. As a downside, some features of each are missing (like streams) and you should make yourself a ware of what features of each are in Linux.
Support
Contrary to popular belief, commercial support for Linux is available. While there is seldom a need for it, companies such as RedHat have telephone and e-mail support for their Linux distribution. Caldera is distributing a “MS Windows killer” in their OpenLinux product. Support contracts and shrink-wrapped packages are available. With the number of users that have Linux on their machines, devices from the latest S3-based video cards to the Mattel PowerGlove have drivers available, and everything in between. The support is often somewhat better than from other operating systems, as the author of a particular driver is sometimes available via e-mail and is often willing to help if your driver is not behaving properly. Some hardware drivers have released patches within 24 hours to users.
What you need
So what do you need in order to run Linux? It varies greatly depending on what you want to do with it. If you're going to use Linux to dialup to the Internet, a low-end 486 with 8MB of memory will suffice just fine. If you want to have a dial-in pool to give access to traveling engineers or sales people, a 100 Mhz 486 is great. If you want a killer development system or something to write a book with, a Pentium or K6 will do just fine.
What's that? A spare SparcStation 1 with nothing better to do? Turn it into a Linux samba server. Let the people running Windows 3.1, 95, or NT access NFS partitions without having all that messy NFS software installed on the PCs. While it's doing that, it could also handle POP e-mail for the same group of people.
You just bought that great new Alpha machine and NT is having trouble with it? Slap Linux on there and be up and running before you remember what NT stands for.
Here's the bare minimum suggestions for running Linux:
386 or better (or Sparc or Alpha or Macintosh)
8MB of memory
300MB of hard drive space - IDE, MFM, or SCSI
ISA, VESA, or PCI bus (Linux doesn't work on MCA quite yet)
Ethernet card or graphics card, monitor and keyboard
Once you have these items assembled, you can use the instructions with the Linux distribution to install Linux on your system. See our appendix on installing the included CD-ROM on your system.
