Running Linux, 5th Edition - Matthias Kalle Dalheimer [12]
Linux's ease of customization—even down to the guts of the kernel—makes the system very attractive for companies that need to exercise control over the inner workings of the system. Linux supports a range of technologies that ensure timely disk access and resistance to failure, from RAID (a set of mechanisms that allow an array of disks to be treated as a single logical storage device) to the most sophisticated storage area networks. These greatly increase reliability and reduce the costs of meeting new regulatory demands that require the warehousing of data for as long as 30 years.
The combination of Linux, the Apache web server, the MySQL database engine, and the PHP scripting language is so common that it has its own acronym—LAMP. We cover LAMP in more detail in Chapter 25.
Kernel hackers were the first to come to Linux—in fact, the developers who helped Linus Torvalds create Linux are still a formidable community. The Linux kernel mailing lists see a great deal of activity, and it's the place to be if you want to stay on the bleeding edge of operating system design. If you're into tuning page replacement algorithms, twiddling network protocols, or optimizing buffer caches, Linux is a great choice. Linux is also good for learning about the internals of operating system design, and an increasing number of universities make use of Linux systems in advanced operating system courses.
Finally, Linux is becoming an exciting forum for multimedia because it's compatible with an enormous variety of hardware, including the majority of modern sound and video cards. Several programming environments, including the MESA 3D toolkit (a free OpenGL implementation), have been ported to Linux; OpenGL is introduced in "Introduction to OpenGL Programming" in Chapter 21. The GIMP (a free Adobe Photoshop work-alike) was originally developed under Linux, and is becoming the graphics manipulation and design tool of choice for many artists. Many movie production companies regularly use Linux as the workhorse for advanced special-effects rendering—the popular movies Titanic and The Matrix used "render farms" of Linux machines to do much of the heavy lifting.
Linux systems have traveled the high seas of the North Pacific, managing telecommunications and data analysis for oceanographic research vessels. Linux systems are used at research stations in Antarctica, and large "clusters" of Linux machines are used at many research facilities for complex scientific simulations ranging from star formation to earthquakes, and in Department of Energy laboratories helping to bring new sources of energy to everyone. On a more basic level, hospitals use Linux to maintain patient records and retrieve archives. The U.S. judiciary uses Linux to manage its entire infrastructure, from case management to accounting. Financial institutions use Linux for real-time trading of stocks, bonds, and other financial instruments. Linux has taken over the role that Unix used to play as the most reliable operating system.
System Features
Linux has surpassed the features found in implementations of Unix and Windows. With the changes offered by IBM's Power Architecture, for example, Linux provides functionality for commodity hardware normally only found on the most expensive mainframes. Additionally, the latest kernels include the structure of Security Enhanced Linux (SELinux) provided by the National Security Agency (http://www.nsa.gov/selinux). SELinux provides the most trusted computing environment available today.
Now add Linux's ability to provide virtualization at the kernel level. Through Xen (http://sourceforge.net/projects/xen), Linux can securely execute multiple virtual machines, each running its own operating system, on a single physical system. This allows enterprises to stop server sprawl and increase CPU utilization.
A Bag of Features