Web Conference 2005 Writing PHP for ITS/ASET Web services Glossary

Glossary

• What is Perl? [top]

  Perl is a programming language used for many purposes, most popularly CGI. Perl is short for Practical Extraction and Reporting Language, as well as (affectionately) Pathologically Eclectic Rubbish Lister.

  Perl is a common example of a scripting language. You can write a program in Perl, such as test.cgi, and then use the Perl interpreter program, /usr/local/bin/perl, to read and execute your code.

• What is a protocol? [top]

  A protocol is basically an agreement on how a discussion should proceed. It is similar to a language in that there are rules for discussion, but is more abstract and only cares about a limited number of points. For example, you can have a protocol on how you will run a meeting, but will still use English as your language. Computers are the same way, but speak in bits (numbers) rather than sounds or scratches on paper/whiteboard. The Free On-Line Dictionary Of Computing has a decent decription.

• What is HTTP? [top]

  HTTP is an acronym for Hyper-Text Transfer Protocol, and is a protocol for describing how Web browsers and Web servers communicate over the Internet.

  The Free On-Line Dictionary Of Computing has this to say .

• What is a process? [top]

  A process is a program that is currently running or executing on a computer. For example, you may have one program called helloworld.cgi, but can run it multiple times on the same computer. Each separate instance is called a process.

• Interpretted vs Compiled program code [top]

  An interpreted program or script is a program written in a language that does not need to be compiled. In order to run, a script must be read, or interpreted by another program. Perl and PHP are examples of languages that are interpreted. PHP is typically interpreted by the Zend engine, which is built into the Apache mod_php module among other programs.

  A program written in a language such as C must be compiled into a binary or executable format, which can be run on the computer without any help of another program.

  Interpreter programs, such as "perl", "php" and mod_php are usually written in a compiled language, such as C.

• What is a database? [top]

  A database is a way to store compartmentalized data for easy retrieval. Unlike files that store data in a sequential fasion, databases store data in small peices that can be retrieved and sorted based on a specific set of criteria called a query.

  There are many different kinds of databases. Popular Relational Database Management Systems (RDBMS) include commercial products such as Oracle, Sybase, SQL Server and DB2, and open source (free) systems such as MySQL and PostgreSQL.

  Unlike Perl and CGI, PHP is relatively new to the Web and grew up when database use with dynamic Web content was more in vogue. Thus, more literature on and software using PHP will expect an RDBMS to be available, the most popular being MySQL. Most languages used for dynamic Web content have ways for accessing databases as well as conventional data stores, like files.

  See also L.A.M.P.

• What is L.A.M.P.? [top]

  LAMP is an acronym for Linux + Apache HTTP server + MySQL + PHP; one of the most popular combinations of technologies for the Web. It combines the dynamic content language PHP with the Apache HTTP Web server software and the MySQL database software, running on the GNU/Linux operating system. All of these are free, open source software programs. Some may replace MySQL for another database system such as PostgreSQL or Linux for another operating system such as FreeBSD or OpenBSD.

If you have any questions, feel free to ask me. Content by: Jeff D'Angelo <jcd@psu.edu> © 2005 See the source for this page Last update on: Fri Jun 10, 2005, 10:01:50 PM