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Unix-like operating system. Operating system Experience in nix-like systems

Today users personal computers A wide selection of operating systems is provided. By far the most common among them are the operating systems of the Windows family and, to a lesser extent, Linux. What to choose? In most cases, laptops already have one or another licensed operating system preinstalled. For ease of selection, operating Windows systems have names corresponding to the area of their use. For example:

Windows 7 Starter – operating system for netbooks. It is distinguished by its exclusively 32-bit design, limited functionality of the Windows Aero interface, lack of a function for quickly switching between users, the inability to change the desktop background, and does not support 64-bit processors. This operating system is only sold as a pre-installed OS, buy it at boxed version impossible.
Windows 7 Home Basic is an inexpensive operating system for home use. It still lacks built-in Windows Media Center Edition (MCE), Windows Aero support, and Multi-Touch support. But it is present standard interface Windows and fast switching between users. This operating system can be purchased in a boxed version.
Windows 7 Home Premium is an advanced system for home use with advanced features. It has built-in Windows MCE, support for up to 4 TV tuners, a full Windows Aero interface, is compatible with Dolby Digital and supports multi-touch. The boxed version contains 2 DVD disc- with 32 and 64-bit versions of the distribution. This OS can be installed on 2-processor workstations.
Windows 7 Professional is an operating system for working with advanced features. An even more reliable system (due to some functions) for business users. Has advanced network capabilities. It also boasts a license for XP Mode and the ability to search for the preferred printer for selected networks. A laptop with such an operating system often comes with a Windows XP distribution.
Windows 7 Ultimate - the name speaks for itself - a universal system for performing any task. Ideal for businesses. If desired, you can always purchase and install the required operating system (except Windows Starter) on your laptop yourself. If you already have a previously purchased “Box” version of the operating system, then it makes sense to purchase a laptop without an operating system so as not to overpay for a pre-installed OS.

Cobalt 02.12.2005

Let’s finally figure out what *nix systems are, how they differ from all of our favorite windows, and most importantly, why you can never become a cool hacker if you don’t master such a system.

In all the books you read before (if you read it, of course), an entire chapter, if not more, was devoted to the history of the origin and development of niks systems. I will not follow this tradition, because... I think that Caesar is a Caesar, and if you study history, Google will help you =). I'll go straight to the main thing. First, let's get one important axiom clear. Linux, Unix, FreeBSD... the list goes on, but I think you've already caught the general trend. All these are so-called *nix systems. They have some differences, but the principle is the same. So when I say Linux, it means that I mean all such systems. But the articles will only be about Linux distributions.

You've probably often come across endless debates on the topic of Linux or Windows on various forums and chats. These debates are inevitable... but completely pointless. There is no better system. There are two different directions. There are problems that cannot be solved using Nix systems, but there are also those where a better solution cannot be found than Linux. For example: install the w2k3 server on an i386 processor, or try raising the DomainController on a Linux basis =). Those. as one great figure once said - Divide and conquer. If you master these two systems equally well, there will be no obstacles left for you in the IT world.

Why do you need Linux? Well, first of all: if you want to be a rule hacker, you should know everything, right? =) Secondly: the overwhelming majority of exploits and hacker programs written for this OS. Well, and most importantly: most of the Internet servers work specifically under NIX systems. Haven't I convinced you yet?! Well then you shouldn't read further ;).

The first question a person has when he decides to learn Linux always sounds the same: what to choose? A person simply gets lost in a sea of information. Such a variety of distributions! RedHat, ASP, ALT, Slacware, Mandrake... the list goes on for a VERY long time. What should you choose from all this variety? You go to the forums and start asking questions like “Which distribution would you recommend for a beginner?” And to your disappointment, you listen to a bunch of contradictory remarks, gradually developing into a fierce argument. Yes, yes, disputes between supporters of different distributions are even hotter than with Windows users! Everyone's opinion is purely subjective. Everyone chooses what he likes best and what is more convenient for him to work with. As a result, you will have to try many different systems until you settle on one thing. I will not advise you to purchase any specific distribution, I will only describe their main differences. There are two types of systems. Without going into details, their main difference lies in the way the programs are installed. There are distributions like Slacware, in which programs are installed ONLY from the source code. And there are so-called RadHat similar ones, they have the ability to install from rpm packages. This is somewhat more convenient, although it becomes necessary to search for the required packages for a long time and tediously, because there is such a thing as dependencies... I’ll go into more detail about installing programs next time. In general, the choice is yours. Remember just one thing: a good distribution should consist of at least 3 CDs!

Military Technical University at Federal service special construction of the Russian Federation

Institute of Industrial, Civil and Transport Construction

Abstract on the subject of computer science on the topic:

« UNIX-like operating systems"

Moscow 2009-10 .

Introduction

History of education and schism

Overview of BSD-like systems

Review file systems unix-like operating systems

Extended File System

Third Extended File System

Table 1 Size restrictions

Fourth Extended File System

Journaled File System

Peculiarities

Unix File System

Kernel linux-kernel-2.6.xx

Desktop environments

Text editors

Conclusion

Bibliography

Introduction

UNIX- a group of portable, multitasking and multi-user operating systems.

The first UNIX system was developed in 1969 by AT&T's Bell Labs division. Since then, a large number of different UNIX systems have been created. Legally, only a few of them have the full right to be called "UNIX"; the rest, although they use similar concepts and technologies, are united by the term "UNIX-like" (Unix- like). For brevity, in this article, UNIX systems mean both true UNIX and UNIX-like operating systems.

The main distinguishing features of UNIX systems include:

· use of simple text files to configure and manage the system;

· widespread use of utilities launched on the command line;

· interaction with the user through a virtual device - terminal;

· representation of physical and virtual devices and some means of interprocess communication as files;

· use of pipelines from several programs, each of which performs one task.

Currently, UNIX is used primarily on servers and also as embedded systems for various hardware. The leader in the OS market for workstations and home use is Microsoft Windows, UNIX takes only second (Mac OS X) and third (GNU/Linux) places.

UNIX systems are of great historical importance because they gave rise to some of today's popular OS concepts and approaches. software. Also, during the development of Unix systems, the C language was created.

History of education and schism

In 1957, Bell Labs began work on creating an operating system for its own needs. Under the leadership of Victor Vysotsky, the BESYS system was created. He subsequently headed the Multics project and then became head of the information division of Bell Labs.

In 1964, third generation computers appeared, for which BESYS capabilities were no longer suitable. Vysotsky and his colleagues decided not to develop a new operating system of their own, but to join the joint project of General Electric and the Massachusetts Institute of Technology Multics. Telecommunications giant AT&T, which included Bell Labs, provided significant support for the project, but withdrew from the project in 1969 because it was not generating any financial benefits. UNIX was originally developed in the late 1960s by Bell Labs employees, most notably Ken Thompson, Denis Ritchie, and Douglas McIlroy. In 1969, Ken Thompson, seeking to implement the ideas that formed the basis of MULTICS, but on a more modest hardware(DEC PDP-7), wrote the first version of the new operating system, and Brian Kernighan came up with a name for it - UNICS (UNIplexed Information and Computing System) - as opposed to MULTICS (MULTIplexed Information and Computing Service). This name was later shortened to UNIX.

In November 1971, a version was released for the PDP-11, the most successful family of minicomputers of the 1970s (in the USSR, its analogues, produced by the Ministry of Electronic Industry, were known as SM EVM and "Electronics", later DVK, produced in Kyiv, Voronezh, Zelenograd). This version was called the “first edition” (Edition 1) and was the first official version. All UNIX implementations start system time from January 1, 1970.

The first versions of UNIX were written in assembly language and did not have a built-in high-level language compiler. Around 1969, Ken Thompson, with the assistance of Denis Ritchie, developed and implemented the B language, which was a simplified version of the BCPL language developed in 1966. Bi, like BCPL, was an interpreted language. In 1972, the second edition of UNIX was released, rewritten in the Bi language. In 1969-1973, a compiled language was developed based on Bi, called C (C).

In 1973, the third edition of UNIX was released, with a built-in C compiler. On October 15 of the same year, the fourth edition appeared, with the system core rewritten in C (in the spirit of the Multics system, also written in the high-level language PL/1), and in 1975 the fifth edition, completely rewritten in C. Since 1974, UNIX has been distributed free of charge to universities and academic institutions. Since 1975, new versions developed outside of Bell Labs began to appear, and the popularity of the system began to grow. Also in 1975, Bell Labs released the sixth edition, known from the widely circulated comments by John Lyons. By 1978, the system was installed on more than 600 machines, primarily in universities. The seventh edition was the last single version of UNIX. It was there that a close to modern interpreter appeared command line Bourne shell.

BSD UNIX, created at the University of Berkeley, began its history in 1978. Its first version was based on the sixth edition. Released in 1979 a new version, called 3BSD, based on the seventh edition. BSD supported useful features such as virtual memory and replacing pages on demand. The author of BSD was Bill Joy. In the early 1980s, AT&T, which owned Bell Labs, recognized the value of UNIX and began creating a commercial version of UNIX. This version, which went on sale in 1982, was called UNIX System III and was based on the seventh version of the system.

An important reason for the UNIX split was the implementation of the TCP/IP protocol stack in 1980. Before this, machine-to-machine communication in UNIX was in its infancy - the most significant method of communication was UUCP (a means of copying files from one UNIX system to another, originally operating over telephone networks using modems).

Two network application programming interfaces have been proposed: Berkley sockets and the TLI transport layer interface. The Berkley sockets interface was developed at the University of Berkeley and used the TCP/IP protocol stack developed there. TLI was created by AT&T according to the transport layer definition of the OSI model and first appeared in System V version 3. Although this version contained TLI and streams, it initially did not implement TCP/IP or other network protocols, but similar implementations were provided by third parties. The implementation of TCP/IP was officially and finally included in the base distribution of System V version 4. This, as well as other considerations, caused the final demarcation between the two branches of UNIX - BSD and System V (the commercial version from AT&T).

Subsequently, many companies, having licensed System V from AT&T, developed their own commercial varieties of UNIX, such as AIX, CLIX, HP-UX, IRIX, Solaris.

In mid-1983, BSD 4.2 was released, supporting work in Ethernet networks and Arpanet. The system has become very popular. Between 1983 and 1990, BSD added many new features, such as the kernel debugger, the NFS network file system, the VFS virtual file system, and greatly improved file networking capabilities.

Meanwhile, AT&T released new versions of its system, called System V. In 1983, version 1 (SVR1 - System V Release 1) was released, which included full-screen text editor vi, curses library, I/O buffering, inode caching. Version 2 (SVR2), released in 1984, implemented file locking, demand paging, and copy-on-write. Version 3 was released in 1987 and included, among other things, TLI, as well as RFS support for remote file systems. Version 4 (SVR4), developed in collaboration with Sun and released on October 18, 1988, supported many BSD features, in particular TCP/IP, sockets, and the new csh command interpreter. In addition, there were many other additions such as symbolic links, ksh shell, NFS network file system (borrowed from SunOS), etc.

Modern UNIX implementations are generally not pure V or BSD systems. They implement features of both System V and BSD.

Overview of GNU/Linux-like systems

Linux runs on a variety of processor architectures such as Intelx86, x86-64, PowerPC, ARM, AlphaAXP, SunSPARC, Motorola 68000, HitachiSuperH, IBMS/390, MIPS, HPPA-RISC, AXISCRIS, RenesasM32R, AtmelAVR32, RenesasH8/300, NECV850, TensilicaXtensa and many others.

Unlike most other operating systems, Linux does not have a single "official" package. Instead, Linux comes in a large number of so-called distributions, in which the kernel Linux connects to GNU utilities and other application programs (for example, X.org), making it a complete multifunctional operating environment.

The most famous GNU/Linux distributions are Arch Linux, CentOS, Debian, Fedora, Gentoo, openSUSE, Red Hat, Slackware, Ubuntu. More full list and usage percentage can be viewed at distrowatch.com

Unlike commercial systems such as Microsoft Windows or Mac OS X, Linux does not have a geographic development center. There is no organization that owns this system; There is not even a single coordination center. Programs for Linux are the result of the work of thousands of projects. Some of these projects are centralized, some are concentrated in firms. Users take part in testing free software, communicate with developers directly, which allows them to quickly find and fix errors and implement new features. Most users for Linux installations use distributions. A distribution is not just a set of programs, but a series of solutions for different user tasks, united unified systems installation, management and updates of packages, configuration and support.

The term "UNIX-like" and the UNIX trademark

Since 2007, there has been a dispute between Wayne R. Gray and The Open Group regarding the use of the word UNIX as a trademark. According to Trademark Trial and Appeal, Board Gray and its company are demanding that The Open Group provide it with documentation for their trademark claims.

Also, in 2007, The Open Group insisted that the German University of Kassel not use "UNIK" as an abbreviation.

Development of UNIX-like systems

UNIX systems began to appear in the late 1970s and early 1980s. Many proprietary versions, such as Idris (1978), Coherent (1983), and UniFlex (1985), aimed to provide business needs with functionality accessible to trained UNIX users.

When AT&T allowed commercial licensing of UNIX in the 1980s, many proprietary systems were developed based on it, including AIX, HP-UX, IRIX, Solaris, Tru64, Ultrix, and Xenix. This largely replaced proprietary clones. Increasing incompatibility between systems led to the creation of interoperability standards, including POSIX and the Common UNIX Specification.

Meanwhile, in 1983, the GNU project was launched, thanks to which it was possible to create an operating system that all computer users could freely use, study, fix, and rebuild. The various UNIX flavors were developed similarly to GNU, often with the same basic components. They primarily served as low-cost replacements for UNIX and included 4.4BSD, Linux and Minix. Some of them served as the basis for commercial UNIX systems such as BSD/OS and Mac OS X. Notably, Mac OS X 10.5 (Leopard) is certified by the Uniform UNIX Specification.

Examples

Most open UNIX system vendors do not seek UNIX certification for their product, even as a compromise: the cost of certification is considered unacceptable. For such systems the term is usually used Freenix. Examples are GNU, Linux, Minix, OpenSolaris, Plan 9 and BSD with their descendants such as FreeBSD, NetBSD and OpenBSD.

There are many proprietary UNIX similarities, such as AIX, HP-UX, IRIX, Mac OS X, LynxOS, QNX, SCO OpenServer, Solaris, Tru64 UNIX (based on OSF/1), UnixWare, Xenix and VxWorks.

Notes

Links

UNIX-like Definition by The Linux Information Project
history of UNIX
Grokline's UNIX Ownership History Project

UNIX-like operating systems

Wikimedia Foundation. 2010.

See what a “Unix-like operating system” is in other dictionaries:

Family tree of UNIX-like operating systems UNIX-like operating system (sometimes abbreviated as *nix) an operating system that was formed under the influence of ... Wikipedia

Family tree of UNIX systems UNIX (read UNIX) family of portable, multitasking and multi-user ... Wikipedia

Family tree of UNIX systems UNIX (read Unix) is a group of portable, multitasking and multi-user operating systems. The first UNIX system was developed in 1969 by the Bell Labs division of AT T. Since then, it has been created ... Wikipedia

Family tree of Unix-like operating systems A Unix-like (sometimes abbreviated as *nix) operating system is a system that was formed under the influence of Unix. The term includes free/open operating systems derived from Bell's Unix... ... Wikipedia

If you have recently started learning Linux and getting comfortable in this vast universe, you have probably often come across the term Unix. Sounds a lot like Linux, but what does it mean? You are probably wondering how unix differs from linux. The answer to this question depends on what you understand by these words. After all, each of them can be interpreted differently. In this article, we'll look at a simplified history of Linux and Unix to help you understand what they are and how they are related. As always, feel free to ask questions or add Additional information in comments.

Unix began its history in the late 1960s and early 1970s at the AT&T Bell Labs research computing laboratories in the United States. Together with MIT and General Electric, Bell Labs research laboratory began developing a new operating system. Some researchers were dissatisfied with the progress of development of this operating system. They moved away from working on the main project and began developing their own OS. In 1970, this system was named Unix, and two years later it was completely rewritten in the C programming language.

This allowed Unix to be distributed and ported to various devices and computing platforms.

As Unix continued to evolve, AT&T began selling licenses to use it in universities as well as for commercial purposes. This meant that not everyone could, as now, freely change and distribute the code of the Unix operating system. Soon, many editions and variants of the Unix operating system began to appear, designed to solve various problems. The most famous of them was BSD.

Linux is similar to Unix in functionality and features, but not in code base. This operating system was assembled from two projects. The first is the GNU project, developed by Richard Stallman in 1983, the second is the Linux kernel, written by Linus Torvalds in 1991.

The goal of the GNU Project was to create a system similar to, but independent of, Unix. In other words, an operating system that did not contain Unix code and could be freely distributed and modified without restrictions, like free software. Since the free Linux kernel could not run on its own, the GNU project merged with the Linux kernel, and the Linux operating system was born.

Linux was designed under the influence of the Minix system, a descendant of Unix, but all the code was written from scratch. Unlike Unix, which was used on servers and large mainframes of various enterprises, Linux was designed for use on home computer with simpler hardware.

Today, Linux runs on a huge number of platforms, more than any other OS, these are servers, embedded systems, microcomputers, modems and even Cell phones. Now the difference between linux and unix will be discussed in more detail.

What is Unix

The term Unix can refer to the following concepts:

The original operating system developed at AT&T Bell Labs, on the basis of which other operating systems are developed.
Trademark, written in capital letters. UNIX belongs to The Open Group, which has developed a set of standards for operating systems - the Single UNIX Specification. Only those systems that comply with the standards can legitimately be called UNIX. Certification is not free and requires developers to pay to use the trademark.
All operating systems are registered with the name Unix. Because they meet the above mentioned standards. These are AIX, A/UX, HP-UX, Inspur K-UX, Reliant UNIX, Solaris, IRIX, Tru64, UnixWare, z/OS and OS X - yes, even those that run on Apple computers.

What is Linux

The term Linux refers only to the kernel. An operating system is not complete without a desktop environment and applications. Since most applications were developed and are currently being developed under the GNU Project, the full name of the operating system is GNU/Linux.

Nowadays, many people use the term Linux to refer to all distributions based on the Linux kernel. On this moment The newest version of the Linux kernel is 4.4, version 4.5 is under development. The numbering of kernel releases was changed from 3.x to 4.x not too long ago.

Linux is a Unix-like operating system that behaves like Unix but does not contain its code. Unix-like operating systems are often called Un*x, *NIX and *N?X, or even Unixoids. Linux doesn't have Unix certification, and GNU stands for GNU not Unix, so in that respect Mac OS X is more Unix than Linux. Nevertheless, the Linux kernel and the GNU Linux OS are very similar to Unix in functionality and implement most of the principles of the Unix philosophy. This is human readable code, storing the system configuration in separate text files, as well as the use of small command line tools, a graphical shell and a session manager.

It is important to note that not all Unix-like systems have received UNIX certification. In certain contexts, all operating systems based on UNIX or its ideas are called UNIX-like, regardless of whether they have a UNIX certificate or not. In addition, they can be commercial and free.

I hope it is now clearer how unix differs from linux. But let's go even further and summarize.

Main differences

Linux is a free operating system with open source code, but the original Unix does not, except for some of its derivatives.
Linux is a clone of the original Unix, but it does not contain its code.
The main difference between unix and linux is that Linux is only a kernel, while Unix was and is a full-fledged operating system.
Linux was developed for personal computers. And Unix is aimed primarily at large workstations and servers.
Today Linux supports more platforms than Unix.
Linux supports more types of file systems than Unix.

As you can see, the confusion usually arises because linux vs unix can mean completely different things. Whatever meaning is intended, the fact remains that Unix came first and Linux came later. Linux was born out of a desire for software freedom and portability, inspired by the Unix approach. It's safe to say that we all owe a debt to the free software movement, because the world would be a much worse place without it.

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