Linux For Dummies. Richard BlumЧитать онлайн книгу.
developed at Bell Telephone Laboratories in the late 1960s. The original architects of UNIX, working back when there were few operating systems, wanted to create one that shared data, programs, and resources both efficiently and securely — something that wasn’t available then (and is still sought after now). From there, UNIX evolved into many different versions; its current family tree is so complicated that it looks like a kudzu infestation!
In 1991, Linus Torvalds was a computer science student at the University of Helsinki in Finland. He wanted an operating system that was like the UNIX system that he’d grown fond of at the university, but both UNIX and the hardware it ran on were prohibitively expensive. A UNIX version called Minix was available for free, but it didn’t quite meet his needs. So, as a computer science student, Torvalds studied Minix and then set out to write a new version himself. In his own words (recorded for posterity on the Internet because this was in an early version of an online chat room), his work was “just a hobby, won’t be big and professional like GNU.”
Writing an operating system is no small task. Even after six months of hard work, Torvalds had made very little progress toward the general utility of the system. He posted what he had to the Internet — and found that many people shared his interest and curiosity. Before long, some of the brightest minds around the world were contributing to Linus’s project by adding enhancements or fixing bugs (errors in the code).
Anatomy of an Open Source Software Project
To the casual observer (and some corporate IT decision makers), Linux appears to be a freak mutation — a rogue creature randomly generated by anarchy. How, after all, can something so complex and discipline dependent as a computer operating system be developed by a loosely knit band of volunteer computer geeks from around the world?
Just as science is constantly attempting to classify and explain everything in existence, technology commentators are still trying to understand how the open source approach can create superior software, especially in cases where there is no charge. Often the reasons have much to do with the usual human desire to fill a need with a solution. When a programmer in the Linux world wants a tool, the programmer simply writes one — or bands together with other people who want a similar package, and they write it together.
GNU who?
Imagine — software created out of need rather than projected profit. Even though UNIX ultimately became expensive proprietary software, the ideas and motives for its creation were originally based on practical needs. What people usually refer to (in the singular) as the Linux operating system is actually a collection of software tools that were created with the express purpose of solving specific computing problems.
The speed of Linux's popularity also wouldn’t be possible without the vision of a man whom Steven Levy (author of the book Hackers) refers to as “The Last of the Great MIT AI-LAB Hackers” — in the original sense of the word hacker is someone who is an expert at coding, not the current popular meaning that implies criminal intent. This pioneer and advocate of freedom software is Richard Stallman.
The Massachusetts Institute of Technology (MIT) has long held a reputation for nurturing the greatest minds in the technological disciplines. In 1984, Stallman, a gifted student and brilliant programmer at MIT, was faced with a dilemma — sell his talent to a company for a tidy sum of money or donate his gifts to the world. He did what we’d all do … right?
Stallman set out on a journey to create a completely free operating system that he would donate to the world. He understands — and continues to live — the original hacker ethic, which declares that information wants to be free. This concept wasn’t new in his time. In the early days of the computing industry, many advancements were made by freely sharing ideas and programming code. Manufacturer-sponsored user groups brought the best minds together to solve complicated problems. This ethic, Stallman felt, was lost when companies began to hoard software as their own intellectual property with the single purpose of profit.
As you may or may not have gathered by this point, widespread and accessible source code is paramount to successful software development. Source code is the term for the human-readable text (as opposed to the unreadable cyber-hieroglyphics in an “executable” file) that a programmer types to communicate instructions to the computer.
Writing computer programs using code that computers can run directly is an extremely arduous task. Modern computer software is usually written in a human-friendly language and then compiled, or translated, into the computer’s native instruction set. To make changes to this software, a programmer needs access to a program’s source code. Most proprietary software comes only as a precompiled product; the software developer keeps the source code for those programs under lock and key.
After determining that his operating system would be built around the conceptual framework of UNIX, Stallman wanted the project name to distinguish his system from UNIX. So, he chose the recursive acronym GNU (pronounced ga-new), which means GNUs not Unix.
To finance the GNU project, Stallman organized the Free Software Foundation (FSF), which sold open source software to help feed the programmers who worked on its continuing development. (Remember, we’re talking free as in freedom, not free lunch.) Although this organization and goal of creating a complete operating system was necessary and important, a much more important piece of the puzzle had to be put into place to protect this new software from big-business pirates — a concern still all too relevant today as a former Linux company tries to hijack ownership of decades of volunteer work from thousands of people around the world.
The GNU General Public License (GPL) is a unique and creative software license that uses copyright law to protect the freedom of the software user, which is usually the opposite of how a copyright works. Generally, a copyright is an enforceable designation of ownership and restriction from duplication by anyone but the copyright holder. When software is licensed under the GPL, recipients are bound by copyright law to respect the freedom of anyone else to use the software in any way they choose. Software licensed with the GPL is also known as copyleft software (the reverse of right, get it?). Another way to remember the GPL is through its ultimate result: Guaranteed Public for Life.
While Stallman's work set the stage for Linux's rapid climb to popularity, the operating system he and his crew were working on took longer than expected. If you're interested in the completed version, go to www.gnu.org/software/hurd/hurd.html.
Who’s in charge of Linux, anyway?
As an open source project evolves, various people emerge as leaders. This leader is often known as the project’s benevolent dictator. A person who becomes benevolent dictator has probably spent more time than anyone else on a particular problem and often has some unique insight. Normally, the words democratic and dictator are never paired in the same sentence, but the open source model is a very democratic process that endorses the reign of a benevolent dictator.
Linus Torvalds is still considered the benevolent dictator of the Linux kernel (the operating system’s core). He ultimately determines what features are added to the kernel and what features aren’t. The community trusts his vision and discretion. In the event that he loses interest in the project, or the community decides that he has gone senile, a new leader will emerge from amongst the very competent people working with him.
Einstein was a volunteer
Someone who is a volunteer or donates time to a project isn’t necessarily providing a second-rate effort (or only working on weekends and holidays). In fact, any human resources expert will tell you that people who choose to do a job of their own free will produce the highest quality products.
The volunteers who contribute to open source projects are often leaders in their fields who depend on community collaboration to get useful work done. The open source concept is no stranger