Programming Languages Used in Websites

Many large websites use multiple programming language in their back-end depending upon the particular feature you're utilizing. The back-end of Google search is powered by Python, although they also make use of PHP, Java, and other language at various locations. (The creator of Python is employed at Google, by-the-by.)

Amazon and eBay primarily rely on CGI, which isn't a programming language, but rather an interface that allows a web application to communicate with a program on the server, such as one written in C. These (typically and predominantly) offline languages that are compiled tend to offer greatly improved processing speeds vs. interpreted languages, such as Python, PHP, or Ruby.

Microsoft-owned websites tend to rely on ASP.net, but although many would say they strictly rely on this technology, it's not true. You'll find Python code and others within Microsoft projects, as well.

Wikipedia relies predominantly on PHP, and Twitter relies mostly on Ruby on Rails, although their most intensive features are handled by Scala, due to scaling problems they've had with Ruby.

BSD Systems

There are a number of Unix-like operating systems based on or descended from the Berkeley Software Distribution (BSD) series of Unix variants. The three most notable descendants in current use are FreeBSD, OpenBSD, and NetBSD, which are all derived from 386BSD and 4.4BSD-Lite, by various routes. Both NetBSD and FreeBSD started life in 1993, initially derived from 386BSD, but in 1994 migrating to a 4.4BSD-Lite code base. OpenBSD was forked in 1995 from NetBSD. Other notable derivatives include DragonFly BSD, which was forked from FreeBSD 4.8, and Apple Inc.'s Mac OS X, with its Darwin base including a large amount of code derived from FreeBSD.

Most of the current BSD operating systems are open source and available for download, free of charge, under the BSD License, the most notable exception being Mac OS X. They also generally use a monolithic kernel architecture, apart from Mac OS X and DragonFly BSD which feature hybrid kernels. The various open source BSD projects generally develop the kernel and userland programs and libraries together, the source code being managed using a single central source repository.

In the past, BSD was also used as a basis for several proprietary versions of UNIX, such as Sun's SunOS, Sequent's Dynix, NeXT's NeXTSTEP, DEC's Ultrix and OSF/1 AXP (now Tru64 UNIX). Of these, only the last is still currently supported in its original form. Parts of NeXT's software became the foundation for Mac OS X, among the most commercially successful BSD variants in the general market.