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Chapter 1: Introduction
The UNIX operating system was developed at AT&T Bell Laboratories in Murray Hill, New Jersey in the late 1960's. Universities and colleges have played a major role in popularizing UNIX. The Computer Science Department at the University of California at Berkeley made so many popular changes to it that one of the two most popular versions in use today is named the Berkeley Software Distribution (BSD) of the UNIX system. The other major version is AT&T's UNIX System V. Many implementations incorporate features of both systems.
Because UNIX was originally designed by programmers to support their own projects, one of its strongest points is that it provides an excellent software development environment. UNIX has a large set of powerful utility programs and tools that allow users to easily build systems and applications. It also has several command interpreters, called shells that can also be used as high-level programming languages. Keep an open mind to the powerful features of UNIX that may be quite different from systems you are familiar with. Some of the important concepts are introduced in Section 5.4 (e.g., pipes and filters, and device-independence).
Bear in mind that there are many UNIX utilities not described in this guide.
The UNIX operating system has four basic components:
Although there are many implementations of UNIX, there are two families of shells. The Bourne shell family and the Berkeley/C shell family. The shell families and the individual shells are discussed in more detail in Chapter 4.
UNIX allows Fermilab to achieve better alignment with the mainstream of computing. The "developmental momentum" is with UNIX and personal computers, and it is primarily for these environments that the new technologies, software products, and software methods are emerging. Other HEP laboratories have also recognized these trends and are moving in this direction.
There are many UNIX platforms, and while there are certainly variations among them, the differences tend to be small. This allows the Computing Division to more effectively support platforms supplied by many vendors, thus eliminating the link to a single vendor whose pricing policies and technology directions are outside of our control.
The general administrative and much of the technical computing load has migrated to MACs and PCs due to the availability of commercial applications. There is also a growing demand from HEP researchers for these applications. The ability to use personal computers as X-terminals offers a real possibility of providing a single platform that allows access to popular applications for word-processing, preparation of presentations, charting, statistical analysis, etc., as well as access to powerful UNIX systems for data analysis and program development.
You first need to determine if you are going to purchase your own desktop UNIX system, get an account on a workgroup UNIX system, or get an account on the central Fermilab UNIX system, FNALU. At this point, you may or may not have a choice of platform; for instance FNALU is comprised of several different platforms. UNIX exists in different flavors on the different vendor platforms, meaning that the UNIX operating system is somewhat customized to each platform. The OS is actually named differently on each platform: AIX on IBM, IRIX on Silicon Graphics, Solaris on Sun, Digital UNIX on Digital[2], and LINUX on PC. The differences between flavors tend to be small.
The "brave new world" of UNIX allows you to set up your work environment and choose your tools to suit your own individual needs. At Fermilab we have been careful to implement and support what we consider to be the most useful of the wide range of available UNIX utilities appropriate for our environment. Still, you will find a much larger array of options than you may be accustomed to. We provide you with defaults for most options, thereby allowing you to get used to the new system gradually, and build your knowledge and proficiency at your own speed.
In order to take full advantage of the flexibility offered, you need to be aware of the options, and you need to make some choices. Two choices you as an individual user need to make initially are the editor and the mail system you want to use. Of course you can change to other ones later. After that, you have the choice of delving further into the marvels of UNIX, or accepting the provided defaults so you can just get to work. UNIX is in fact usable by ordinary mortals as well as by sophisticated hackers! Throughout this manual we give some guidance for making choices.
The available editors come in three basic types:
The types of mail systems offered include:
Instead of a single command interpreter and user interface, several shells have been developed for UNIX, a number of which we provide and support. Until you get a good idea of what the advantages are of one shell over another, we recommend that you just use the default shell provided. You can change it later.
The choices that you need to make should not be overwhelming. Most people find the range of choices empowering once they're familiar with the system.