Experience in nix-like systems. Operating system

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 that you read before (if you read, of course), a whole chapter, if not more, was devoted to the history of the origin and development of nix systems. I will not follow this tradition as I think that kesarby is kesarevo, and if you study history, google will help you =). I’ll go straight to the main point. First, let's clarify one important axiom. Linux, Unix, FreeBSD ... the list goes on, but I think you've already caught the general trend. These are all 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.

Probably you have often stumbled upon endless debates on the topic of Linux or Windows on all kinds of forums and chats. These arguments are inevitable ... but completely pointless. There is no better system. There are two different directions. There are problems that cannot be solved by means of nix systems, but there are also those where you cannot find solutions better than Linux. For example: install the w2k3 server on an i386 processor, or try to raise DomainController =) on Linux. Those. as one great figure once said - Divide and conquer. If you master these two systems equally well, there will be no barriers in the IT world for you.

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

The first question that arises in a person when he decides to study Linux, always sounds the same: what to choose? A person is simply lost in the sea of ​​information. Such a variety of distributions! RedHat, ASP, ALT, Slacware, Mandrake ... the list is VERY long. What should you choose from all this variety? You go to forums and start asking questions like "What distribution kit would you recommend for a beginner?" And to your disappointment, you listen to a bunch of contradictory remarks, gradually turning into a fierce argument. Yes, the disputes between adherents of different distributions are even hotter than with Windows! Everyone's opinion is purely subjective. Everyone chooses what he likes best and what is more convenient for him to work in. 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 kit, 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 the installation of programs is performed 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. there is such a thing as dependencies ... I will dwell on the installation of programs in more detail sometime next time. In general, the choice is yours. Just remember one thing: a good distribution should consist of at least 3 CDs!

The term "UNIX-like" and the UNIX trademark

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

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

Categories

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 available to trained UNIX users.

When AT&T authorized commercial UNIX licensing in the 1980s, many proprietary systems developed based on this, including AIX, HP-UX, IRIX, Solaris, Tru64, Ultrix, and Xenix. This largely supplanted proprietary clones. The growing incompatibility between systems has led to the creation of interoperability standards, including POSIX and the Unified UNIX Specification.

Meanwhile, in 1983, the GNU project was launched, thanks to which it was possible to make an operating system that all computer users could freely use, study, fix, rebuild. The various UNIX similarities have been developed in a similar fashion to GNU, often with the same core components. They primarily served as a cheap replacement for UNIX and included 4.4BSD, Linux, and Minix. Some of these have 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 Unified UNIX Specification.

Examples of

Most manufacturers of open source UNIX systems do not seek UNIX certification for their product, even as compromising evidence: 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 flavors such as AIX, HP-UX, IRIX, Mac OS X, LynxOS, QNX, SCO OpenServer, Solaris, Tru64 UNIX (based on OSF / 1), UnixWare, Xenix, and VxWorks.

see also

Notes (edit)

Links

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

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

UNIX family tree of similar operating systems UNIX similar operating system (sometimes abbreviated as * nix) an operating system that was influenced by ... Wikipedia

UNIX family tree of UNIX systems (unix readable) a family of portable, multitasking and multiuser ... Wikipedia

UNIX family tree of UNIX systems (unix readable) group of portable, multitasking, and multiuser operating systems. The first UNIX system was developed in 1969 in the Bell Labs division of AT T. Since then ... Wikipedia

Family tree of Unix-like OS Unix-like (sometimes abbreviated * nix) operating system is a system that was influenced by Unix. The term includes free / open source operating systems derived from Bell's Unix ... ... Wikipedia

Family tree of Unix-like OS Unix-like (sometimes abbreviated * nix) operating system is a system that was influenced by Unix. The term includes free / open source operating systems derived from Bell's Unix ... ... Wikipedia

Family tree of Unix-like OS Unix-like (sometimes abbreviated * nix) operating system is a system that was influenced by Unix. The term includes free / open source operating systems derived from Bell's Unix ... ... Wikipedia

Family tree of Unix-like OS Unix-like (sometimes abbreviated * nix) operating system is a system that was influenced by Unix. The term includes free / open source operating systems derived from Bell's Unix ... ... Wikipedia

Family tree of Unix-like OS Unix-like (sometimes abbreviated * nix) operating system is a system that was influenced by Unix. The term includes free / open source operating systems derived from Bell's Unix ... ... Wikipedia

Family tree of Unix-like OS Unix-like (sometimes abbreviated * nix) operating system is a system that was influenced by Unix. The term includes free / open source operating systems derived from Bell's Unix ... ... Wikipedia

Military Technical University under the Federal Service for 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

Education history and schism

Overview of BSD-like systems

Overview of file systems of unix-like operating systems

Extended File System

Third Extended File System

Tab. 1 Size limitations

Fourth Extended File System

Journaled File System

Peculiarities

Unix File System

Linux-kernel-2.6.xx

Desktop environments

Text editors

Conclusion

Bibliography

Introduction

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

The first UNIX system was developed in 1969 by AT&T Bell Labs. 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 run on the command line;

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

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

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

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

UNIX systems are of great historical importance, as thanks to them, some of the popular concepts and approaches in the field of OS and software have spread. Also, during the development of Unix systems, the C language was created.

Education history and schism

In 1957, work began at Bell Labs to create an operating system for its own needs. The BESYS system was created under the leadership of Viktor Vysotsky. Subsequently, he led the Multics project, and then became the head of the information division of Bell Labs.

In 1964, computers of the third generation appeared, for which the capabilities of BESYS 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 substantial support to the project, but withdrew from the project in 1969 because it did not bring 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 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). Later this name was shortened to UNIX.

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

The first versions of UNIX were written in assembly language and did not have a built-in high-level 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 called C (C) was developed on the basis of Bi.

In 1973, the third edition of UNIX came out, 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 PL / 1 high-level language), and in 1975 - the fifth edition, completely rewritten in C. Since 1974, UNIX has been distributed free of charge to universities and academic institutions. 1975 saw the emergence of new versions developed outside Bell Labs and the rise in popularity of the system. Also in 1975, Bell Labs released the sixth edition, known for widely diverted comments from John Lyons. By 1978, the system had been installed on more than 600 machines, primarily in universities. The seventh edition was the last unified version of UNIX. It was in it that the Bourne shell, a command line interpreter close to the modern one, appeared.

Since 1978, BSD UNIX, created at the University of Berkeley, begins its history. Its first version was based on the sixth edition. In 1979 a new version called 3BSD was released, based on the seventh edition. BSD supported such useful features as virtual memory and on-demand paging. BSD was written by Bill Joy. In the early 1980s, AT&T, which owned Bell Labs, recognized the value of UNIX and began building 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 split in UNIX was the implementation in 1980 of the TCP / IP protocol stack. Until then, machine-to-machine communication in UNIX was in its infancy - the most essential method of communication was UUCP (a means of copying files from one UNIX system to another, originally working 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 OSI model's transport layer definition and first appeared in System V version 3. Although this version contained TLIs and streams, it originally did not include TCP / IP or other network protocols, but such implementations were provided by third parties. ... The TCP / IP implementation was formally and definitively included in the base distribution of System V version 4. This, along with other considerations, caused the final demarcation between the two UNIX branches - BSD and System V (the commercial version from AT&T).

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

BSD 4.2 was released in mid-1983, supporting Ethernet and Arpanet. The system has become quite popular. Between 1983 and 1990, many new features were added to BSD, such as a kernel debugger, NFS, VFS, and vastly improved file networking capabilities.

In the meantime, AT&T was releasing new versions of its system, called System V. In 1983, version 1 (SVR1 - System V Release 1) was released, which included a full-screen vi text editor, curses, 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, the TLI, as well as the support for remote file systems RFS. Version 4 (SVR4), developed in collaboration with Sun and released on October 18, 1988, supported many BSD features such as TCP / IP, sockets, and the new csh shell. In addition, there were many other additions, such as symbolic links, the ksh shell, NFS (borrowed from SunOS), etc.

Modern UNIX implementations are generally not pure V or BSD systems. They implement the capabilities 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, NECXtensa850 and many others.

Unlike most other operating systems, Linux does not come with a single "official" package. Instead, Linux comes in a large number of so-called distributions in which the kernel Linux connects with GNU utilities and other application programs (such as X.org), making it a complete, feature-rich operating environment.

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

Unlike commercial systems such as Microsoft Windows or Mac OS X, Linux does not have a geographic center of development. There is no organization that owns this system; there is not even a single focal point. Linux software is the result of thousands of projects. Some of these projects are centralized, some are concentrated in firms. Users take part in testing free software, communicate directly with developers, which allows them to quickly find and fix bugs and implement new features. Most users use distributions to install Linux. A distribution kit is not just a set of programs, but a series of solutions for various user tasks, united by uniform systems for installing, managing and updating packages, configuring and supporting.

Today, personal computer users have a wide range of operating systems to choose from. By far the most common among them are the operating systems of the Windows family and, to a lesser extent, Linux. What should you choose? On laptops, in most cases, one or another licensed operating system is already preinstalled. For convenience of choice, Windows operating systems have names corresponding to their area of ​​use. For example:

• Windows 7 Starter - Operating system for netbooks. It differs exclusively in 32-bit execution, limited functionality of the Windows Aero interface, lack of a function for fast switching between users, inability to change the desktop background and does not support 64-bit processors. This operating system is sold only as a pre-installed OS, it is not possible to buy it in a boxed version.
• Windows 7 Home Basic is a low-cost operating system for home use. It still lacks built-in Windows Media Center Edition (MCE), Windows Aero support, and Multi-touch support. But there is a standard Windows interface and fast switching between users. This operating system can be purchased in a boxed version.
• Windows 7 Home Extended - a system for advanced 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 multitouch. The boxed version contains 2 DVD discs at once - with 32 and 64-bit versions of the distribution kit. This OS can be installed on 2-processor workstations.
• Windows 7 Professional is an advanced operating system. An even more reliable system (due to some functions) for business users. Has advanced networking capabilities. It also boasts an XP Mode license and the ability to search for the preferred printer for selected networks. In a set of a laptop with such an operating system, you can often find a Windows XP distribution kit.
• Windows 7 Ultimate - the name speaks for itself - is a universal system for performing any tasks. Ideal for businesses. If desired, the required operating system (except for Windows Starter) can always be purchased and installed on a laptop by 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 the pre-installed OS.