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What is UNIX?

UNIX is the name of an operating system which began development at Bell Labs in 1969, led by Ken Thompson and Dennis Ritchie. This name is also used to collectively refer to all operating systems built on similar principles. The name is pronounced /'junəks/, like the word “eunuchs,” but its original name, Unics, was short for the “UNiplexed Information and Computer Service.”

The term “UNIX-like” is often used to describe OSs that are built on similar principles to UNIX, but either are not certified as an official UNIX version by the Open Group, who owns the trademark, or cannot be traced directly back to Bell Labs. To be clear, Dennis Ritchie did not hold to such a strict definition of UNIX.

How has UNIX become so prominent among operating systems?

There were four major factors which contributed to the spread of UNIX in its early days.

Unlike many OSs of the era, the earliest versions of UNIX included a hierarchical file system, which included folders and subfolders. Even MS-DOS as late as 1983 lacked such a feature.

Early UNIX programmers at Bell Labs championed a philosophy whereby every program was devoted to one task, and doing it well. One might select certain segments of a file (grep), while one show the results of systematically altering a file (sed). This is related to the use of the UNIX pipeline, which allowed the output of one program to be used as the input of another, without having to save this output temporarily to (then) precious hard drive space.

The C language was invented to write UNIX code. As the 1970s rolled on, increasing portions of the system code for UNIX was written in C rather than processor-specific machine language, allowing it to be ported across a diverse set of computer architectures.

Finally, Bell Labs’ parent company, AT&T, had been in hot water with the US federal government for monopolistic practices. As part of an agreement with Washington, AT&T was not permitted to enter industries that were not strictly related to the telephone business. AT&T cautiously avoided entering the computing industry and charged clients for installation fees of UNIX alone. This was a double-edged sword, as AT&T did not help maintain clients’ UNIX installations. This necessitated custom bug fixes and add-ons to UNIX among its userbase.

What is Linux, and what is its relation to UNIX?

To explain Linux, one must explain what exactly an OS and a kernel are. An operating system is a special kind of powerful computer program that controls the resources of other computer programs and directly interfaces with a computer’s hardware. The portion of an OS that interfaces with hardware is called the kernel.

A number of attempts throughout the 1980s were made to get UNIX onto home computers, few with lasting success. Being written in C rather than machine code meant UNIX could be easily ported to different computers, but required way more resources from a CPU, which the i386 processor found on many home computers had difficulties keeping up with.

One such attempt was MINIX. A student at the University of Helsinki named Linus Torvalds found MINIX to be fairly usable, but had some objections to its kernel’s design, and created his own kernel. After some coaxing by friends of his, he named the kernel Linux and eventually released it as open-source software. This allowed others to use it as the basis of various operating systems. An OS using the Linux kernel is called a Linux distribution.

Linux is not, and never has been, the entirety of any OS. It is strictly a kernel used to create UNIX-like OSs. When its name is discussed among complete OSs, it is generally being used collectively to refer to the OSs which utilize its kernel.

Is it possible to use UNIX without a command line?

If you use any current Apple product or almost any smartphone, you already do. When Steve Jobs left Apple in 1985, he founded NeXT, which sold UNIX workstations. Apple bought NeXT when they needed Steve Jobs back at the helm and rebranded the particular UNIX-like system on NeXT computers as OS X, later macOS. Other Apple products use OSs based on early macOS versions. This is besides the existence of various Linux distributions that include a GUI. Many people, who are either tired of the constant, long software updates for Windows or are concerned about its backdoors, switch to one of these distributions and never once use the command line. In addition, Android’s OS is based on the Linux kernel.

What does open-source mean? What does it mean that Linux is “free?”

Open-source software has had its source code released willingly by its developers to the general public, to be viewed and (if so desired) altered. It is synonymous with the term “free software,” as used by computing professionals. The terms are indeed confusing, which has prompted programmer Richard Stallman to humorously clarify that “free software” means, “‘Free’ as in speech, not beer.” In practice, almost no free software costs anything to acquire or use. The technical term for software whose source code cannot be freely viewed by the general public but does not cost anything is freeware. Chrome is freeware, while Firefox is free software.

Doesn’t the fact that anyone can view the source code for Linux make it more vulnerable to hackers?

Not at all. At any point, hundreds of people are watching the source code for various Linux distributions like a hawk. If a security flaw is found, whoever finds it will sound the alarm, allowing it to be patched. By contrast, proprietary OSs might have flaws that are not monitored closely by their developers (and some which are exploited by corporations and governments to spy on users), and thus are not patched.

What are the practical uses for UNIX? Besides Apple products, are any UNIX-like systems used by more than a niche quorum of computer nerds?

UNIX-like systems have had a constant presence in servers and businesses worldwide since the 1970s. Almost any company you can name has a UNIX installation for their servers. Almost any current movie or TV show you watch was composited and rendered on a machine running a UNIX-like system. Almost every website is hosted on a UNIX-like system. Embedded UNIX systems are found in everything from airplanes to modems.

[TIL] Tại sao git ra đời? Git nghĩa là gì?

Git được Linux Torvalds – nhà sáng lập của Linux kick off (more…)

Executive director of Linus Torvald’s Linux Foundation, Jim Zemlin, declared that 2013 was the year of Linux in everything as it reached out from smartphones, tablets, consumer appliances and cars, to the open cloud and high-performance computers, to gaming platforms and more while recognizing Linus Torvald’s contribution to those successes.

Linux on a phone. Courtesy of ryan_worl.

Linux Foundation is a kernel development community for Linux operating system which was founded by Linus Torvalds in late 1980s. Zemlin, in his report, notes that more than 1.5m Android, which is based on linux software, phone activations are happening every day. Many high-tech cars such as the Cadillac CTS sedan and the all-electric Tesla Model S run Linux. Top contributing companies to Linux’s development include Canonical, Google, and Samsung. The cloud computing space is one of the fastest growing areas of IT with Gartner forecasting it will account for the bulk of IT spending in 2016, said Zemlin. Gaming industry was flourished by Linux as well as Valve and SteamOS adopted Linux software for their brands. Zemlin say, these developments represent a major shift in the way the gaming industry looks at Linux and open source and is poised to transform the competitive dynamic among companies in that space and the way users interact with their games. Linux is making this happen. http://youtu.be/ajRLaiTICwI

Is it all really worth it?

Many Linux lovers are worried that Microsoft’s new Secure Boot technology will make it more difficult to get the open source operating system onto machines that originally ship with Windows 8. But Linux founder Linus Torvalds believes that the complaints are overblown. The bigger issue, he says, is that Secure Boot can be hacked. Microsoft has set up a system in which encryption keys are needed to secure communication between the operating system and the machine’s firmware, the embedded software that talks to its hardware. “The real problem, I feel, is that clever hackers will bypass the whole key issue,” Toralds tells ZDNet. When Microsoft first unveiled its unified extensible firmware interface, or UEFI, many complained that it would keep Linux off of machines that originally ship with Windows 8, due to officially arrive this fall. But since then, Linux distributor Red Hat and others have worked to massage the technology so that third party OS’s are accommodated. Essentially, Red Hat and other OS makers must distribute their own keys to firmware makers, and in order to do so for Linux distros such as Fedora, they must pay a one-time $99 fee to VeriSign, which helps distribute the keys. Some are still concerned that this will put Linux at a disadvantage, but Torvalds thinks they should lighten up — at least a little. “I’m certainly not a huge UEFI fan, but at the same time I see why you might want to have signed bootup etc. And if it’s only $99 to get a key for Fedora, I don’t see what the huge deal is,” he tells ZDNet. But he believes that Secure Boot could be vulnerable. He argues that hackers will either find a way to get the right keys — “how many of those private keys have stayed really private again? Oh, that’s right, pretty much none of them,” he says — or they’ll take advantage of security bugs so that they can get in with no keys at all. George Hotz, the man who cracked Sony’s attempts to keep third party operating systems and unlicensed games off of the PlayStation 3, sees Torvalds’ point. But he downplays the issue. “Overall, I don’t see it as the sky is falling,” he tells Wired. He takes the wider view that secure boot is just one of so many ways Microsoft is trying to keep Windows relevant in a world that’s moving elsewhere. “I think Windows 8 is a last ditch attempt by Microsoft to try to cling to ownership of the dominant API that they lost when the Web rose to prominence.” Matthew Garrett — a Red Hat engineer who has worked closely with Secure Boot — believes it’s just a matter of time before the technology is hacked, but he believes that Microsoft will ultimately keep hackers at bay. “Yes, Secure Boot will be broken,” he says. “And then it will be fixed. And after this happens a few times, there will be no further breaks.” He also says that hackers are unlikely to secure legitimate keys by pretending to be an operating system vendor such as Red Hat. “Secure Boot is unlikely to be broken via fundamental flaws in its implementation, and there’s no evidence that public availability of the signing service will result in an explosion of boot level malware.”

Twenty years ago last Friday, a University of Helsinki student announced a software project he had started in his digs. Today, given you’re reading this, you’re using his creation.