What is Unix and why is it so important?

Source: Internet
Author: User

What is Unix and why is it so important?
Most operating systems can be divided into two different families. In addition to Microsoft's Windows NT-based operating system, almost all others can be traced back to Unix. Orbis OS running on Linux, Mac OS x, Android, iOS, Chrome OS, and PlayStaion 4 and various firmware running on the vro, all these operating systems are generally called "Unix-like" operating systems.

Unix design is still being applied.

Unix was born in AT&T's Bell lab in the late 1960s S. Some of the major design factors in the first release of Unix are still in use today.

One of these designs is the "Unix philosophy", which establishes a small modular application and does only one thing and completes it well. If you are familiar with Linux terminals, you should be familiar with this-the system provides a large number of applications, you can use pipelines or other features to form different combinations to complete more complex tasks. Even graphic interfaces often call simpler applications in the background to perform time-consuming tasks. This mode also makes it easier to create a terminal script, and some simple tools are combined through text to do complicated things.

Unix also designed a single file system through which programs can communicate with each other. That's why "Everything is a file" in Linux-including hardware files and special files that provide system information and other data. That's why only Windows systems have disk drive letters, which are inherited from DOS-in other operating systems, all files are part of a single directory structure.

Systems derived from Unix

Similar to any history that can be traced back for 40 years, the history of Unix and its derived systems are messy. For simplicity, we roughly divide Unix-derived systems into two groups.

A group of Unix-derived systems are developed by academia.

The first is BSD (Berkeley Software release), an open-source Unix-like operating system. BSD still exists in systems such as FreeBSD, NetBSD, and OpenBSD. NeXTStep is developed based on the initial version of BSD. Apple's Mac OS x is based on NeXTStep, and iOS is based on Mac OS X. Many other operating systems, including Orbis OS running on PlayStation 4, also originate from various BSD operating systems.

Richard Stallman created the GNU project to oppose the increasingly strict restrictions on AT&T's Unix software agreement terms. MINIX is a Unix-like operating system designed for educational purposes, while Linux is inspired by MINIX. The Linux we are familiar with today is actually called GNU/Linux, because it is composed of Linux kernel and a large number of GNU applications. GNU/Linux does not directly inherit from BSD, But it inherits Unix design and is rooted in academia. Today, many operating systems, including Android, Chrome OS, Steam OS, and a large number of embedded operating systems used on a variety of devices, are based on Linux.

Another group is commercial Unix operating systems. AT&T UNIX, SCO UnixWare, Sun Microsystem Solaris, HP-UX, ibm aix, sgi irix-many large enterprises want to build and authorize their own versions of Unix. They are not common today, but some of them still exist.

Thank you! Wikimedia Commons

Rise of DOS and Windows NT

Many people want Unix to become an industrial standard operating system, but DOS and ibm pc-compatible computers are gaining popularity. Microsoft's DOS has become the most successful among many DOS systems. DOS does not reference Unix at all, which is why Windows uses a backslash to divide file paths, while all other systems use a forward slash. This decision was made in the early DOS system, and later Windows versions inherited this setting, like BSD, Linux, Mac OS X, similar to other Unix-like operating systems that inherit many Unix design factors.

Windows 3.1, Windows 95, Windows 98, and Windows ME are both based on DOS. At that time, Microsoft was already developing a more modern and stable operating system called Windows NT-which meant "new Windows technologies ". Windows NT is finally applied to normal computer users through Windows XP, but previously it was only used for Windows 2000 and Windows NT for enterprise users.

Today, all Microsoft operating systems are based on the Windows NT kernel. Windows 7, Windows 8, Windows RT, Windows Phone 8, Windows Server, and OS on Xbox One are all using the Windows NT kernel. Unlike most other operating systems, Windows NT is not developed into a Unix-like operating system.

Of course, Microsoft does not start completely from scratch. To maintain the compatibility between DOS and earlier versions of Windows software, Windows NT inherits many settings in DOS, such as disk drive letters, backslash to distinguish file paths, and forward slashes as command line parameters.

Why is it very influential?

I wonder if you have read Mac OS X terminals or file systems. Have you noticed that they are so similar to Linux, but so different from Windows? Okay, because-Mac OS X and Linux are both Unix-like operating systems.

By understanding this history, you can understand what a "Unix-like" operating system is and why so many operating systems seem similar, while Windows is so distinctive. This can also explain why Linux geeks are so familiar with Compaction on Mac OS X, while Command Prompt and PowerShell on Windows 7 are incompatible with other Command line environments.

This is just a history that passes by quickly, helping you understand how it has evolved to the present without getting into details. If you want to learn more, you can find many books on Unix History.

Thank you! Peter Hamer on Flickr, Takuya Oikawa on Flickr, CJ Sorg on Flickr

Via: http://www.howtogeek.com/182649/htg-explains-what-is-unix/

Translator: zpl1025 Proofreader: wxy

This article was originally translated by LCTT and launched with the Linux honor in China

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