The first three letters in LAMP stand for Linux, Apache, and MySQL, which comprise the OS, Web server, and database management system, respectively. Some developers dispute that Linux should be part of the equation; the same stack runs on Mac OS X, Unix, and even Windows. Linux, however, has the advantage of offering the same low cost and access to source code that the other components provide. The P in LAMP is a matter of preference; it stands for either Perl, PHP (PHP: Hypertext Preprocessor), or Python, although some would argue that other scripting languages, such as Ruby, deserve a place at the table as well.
Whereas J2EE and .Net development extend classic systems programming techniques and technologies to the Web, LAMP can be seen as a more direct descendent of the CGI programming model from the early days of Web development. The PHP scripting language, in particular, evolved with Web development squarely in mind, including numerous features designed to eliminate the drudgery of CGI programming. Whats more, the process overhead associated with traditional CGI has been all but eliminated in the modern LAMP platform. By loading either Perl, PHP, or Python as an Apache module, Web applications can execute quickly and efficiently.