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: http://itpm.msu.su/LDP/LinuxAdministration/linux-admin-made-easy-3.html
Дата изменения: Sun Apr 18 13:35:40 1999 Дата индексирования: Mon Oct 1 21:58:23 2012 Кодировка: |
Welcome to Linux!
Linux is a true 32-bit operating system that runs on a variety of different platforms, including Intel, Sparc, Alpha, and Power-PC (on some of these platforms, such as Alpha, Linux is actually 64-bit). There are other ports available as well, but I do not have any experience with them.
Linux was first developed back in the early 1990s, by a young Finnish then-university student named Linus Torvald's. Linus had a "state-of-the-art" 386 box at home and decided to write an alternative to the 286-based Minix system (a small unix-like implementation primarily used in operating systems classes), to take advantage of the extra instruction set available on the new chip, and began to write a small bare-bones kernel.
Eventually he announced his little project in the USENET group comp.os.minix, asking for interested parties to take a look and perhaps contribute to the project. The result has been phenomenal!
The interesting thing about Linux is, it is completely free! Linus decided to adopt the GNU Copyleft license of the Free Software Foundation, which means that the code is protected by a copyright -- but protected in that it must always be available to others.
Free means free -- you can get it for free, use it for free, and you are even free to sell it for a profit (this isn't as strange as it sounds; several organizations, including Red Hat, have packaged up the standard Linux kernel, a collection of GNU utilities, and put their own "flavour" of included applications, and sell them as distributions. Some common and popular distributions are Slackware, Red Hat, SuSe, and Debian)! The great thing is, you have access to source code which means you can customize the operating systems to your own needs, not those of the "target market" of most commercial vendors.
Linux can and should be considered a full-blown implementation of unix. However, it can not be called "Unix"; not because of incompatibilities or lack of functionality, but because the word "Unix" is a registered trademark owned by AT&T, and the use of the word is only allowable by license agreement.
Linux is every bit as supported, as reliable, and as viable as any other operating system solution (well, in my opinion, quite a bit moreso!). However, due to its origin, the philosophy behind it, and the lack of a multi-million dollar marketing campaign promoting it, there are lot of myths about it. People have a lot to learn about this wonderful OS!
I've been using Linux for several years, and I like to think I know a bit about the operating system and what it can and cannot do. As I'm an avid USENET reader, I follow the latest developments and of course, the various flame-wars that invariably crop up (those darn cross-posting advocacy people! ;-) ). I've seen my share of myths (often called FUD -- "Fear, Uncertainty, Doubt" which seems to be a common tactic used by commercial technology vendors to frighten their market away from competing technologies) that more than a few people believe. So, let me try to run down a few of the more common ones and attempt to shatter them. :-)
Some people seem to have the notion that, because a piece of software was written by volunteers with no profit motive in mind, that the results must clearly be inferior to commercial-grade offerings.
This may have been true in the past (I mean, there was a lot of freeware which was absolute garbage in the DOS and early Windows world), but it is most certainly not true in recent days.
The power of the Internet has made it possible to bring together some of the brightest minds in the globe, allowing collaboration on projects they find interesting. The people who have put a hand into developing Linux or the thousands of GNU utilities and applications packages are from a diverse background, and all of them have different personal reasons for wanting to contribute.
Some are hard-core hackers who develop for the love of coding, others have a need for something (for example, a network traffic monitor for a LAN at work) and decide to write it themselves, others are academics and computer scientists who are using Linux for its research qualities.
Unlike a commercial offering where a package is developed and sold, source code excluded, to the end-user, code used in Linux is scrutinized, debugged, and improved upon by anyone who has the interest and ability. This act of peer-review is one of the reasons that Linux offers the high reliability and high performance that it does.
Don't forget: The Internet itself was built and runs almost exclusively on Open Source projects. The e-mail you exchange on a daily basis with people around the world has an 80% chance of being handled on one or both ends by Sendmail, the web pages you browse while "Surfin' the Web" are served to you by Apache on over 50% of the world's web sites. Reliable enough for you?
Hearing this myth somewhat sickens me. And supposedly the "other" vendors do offer support? I've had personal experience with one very popular commercial operating system, where the vendor's so-called "support" was completely useless.
First of all, there is support for Linux. Yes, commercial support. There are some companies that can provide as much support as you are willing to pay for; offering telephone and e-mail support, many offering to come right to your door to deal with the problem!
However, in 99% of the situations you will run into with Linux, you will be able to accomplish what you wish if you can simply get the answer to a question or two. This is easily accomplished on USENET or on any of the many mailing lists available!
I've never had a problem I couldn't find a solution to, by either searching on http://www.dejanews.com/, or by asking in one of the comp.os.linux.* newsgroups. Normally I can receive an answer to any of the support issues I ask about within three to twelve hours of my posting.
Another interesting aspect of Linux is that, because the source code for the entire kernel and most of the other operating system components is freely available, key-support issues such as security, denial of service, or CPU bugs (such as Intel's F00F fatal exception) are tracked down and solved very quickly -- usually an order of magnitude faster than solutions offered for similar or identical problems on the commercial offerings. So, where's the commercial support!?
There are countless others that I would like to debunk, but that is beyond the scope of this document. However, for further myth debunking, check out the "Linux Myth Dispeller" at http://www.KenAndTed.com/KensBookmark/linux/index.html as well as "The Linux FUDfactor FAQ" at http://www.geocities.com/SiliconValley/Hills/9267/fud2.html
I use Linux both at work and at home.
At my place of employment, we are using Linux to provide Internet services for hundreds of users. These services include TACACS (dial-in modem user) authentication, web page hosting and proxy caching, as well as SMTP and POP services. In addition, we are using Linux to provide NFS services, and also for providing and mounting SMB-protocol (WfW/Win95/WinNT) file & print and FAX services using the Samba package.
At home, I use Linux for my personal needs, such as Internet services, software development, and of course game playing (seeing Quake II running on a Linux box is a thing of beauty)! One of the things I love about Linux is, no matter how hard I pound on it, it does not crash! It's also a great way to learn, develop, and maintain my Unix skills.
I am using the Red Hat 5.2 distribution of Linux (see http://www.redhat.com/ for more information). This distribution includes all the necessary software for a full-blown unix system -- shells, compilers & interpreters, networking support, the X Window System, and all Internet services (eg. Mail, news, web server, telnet, etc.). The distribution comes standard with Linux kernel 2.0.36.
At my place of employment, the Linux-based system we use as our primary Internet server has the following configuration:
We have a second system -- an even nicer Intel box -- also running Red Hat 5.2, running in another office location. It provides networked file & print services via Samba, local web caching via Squid, and secondary DNS services. Unfortunately, this box is over 50 km away from where I usually work, and therefore it's left pretty much on its own -- yet this baby is really my pride and joy! Here are some specs:
as hardware RAID level 5 array,
Having an incredible 24+ Gb of available storage space, with redundant storage configured as a hardware RAID5 array is a humbling feeling. The Mylex RAID controller works great, and I would not hesitate to recommend it to others seeking a hardware RAID solution! (If you are interested in configuring your Linux system with a RAID array, see the "High Availability with RAID" section for details.)
We have four other Linux systems in place; an Alpha, a Sparc, and two Intel boxes; two of which are being used in production, and then there is my own personal system at home, but I won't bore you with the details.
This document will attempt to remain as hardware independent as possible but it may be helpful to you if you know where I am coming from as far as hardware is concerned.