Open Source Software is software developed for the public domain, and includes the source code to the programs.  Unlike proprietary software, there are many contributors to major open source software, and the source code gets peer review.  Major computer manufactures support open source.  IBM is a major proponent of building software systems using open source programs

Reaves Technical Services promotes the use of appropriate Open Source programs when they offer similar or better features than proprietary systems.  Recommended packages:

 IPCOP pc based firewall appliance, intrustion detection system, router.  

 SME pc based fully featured mail server, including virus and spam detection for email.  

 Open Office productivity package similar to Microsoft's Office.  Includes word processing, spreadsheet, database, presentation functions. 

 Linux operating system.  Unix based, dozens of distributions and well supported on the internet.  

 Samba, file sharing system that works for Windows clients.  

 Apache, web server software, that provides the hosting service for web pages.

 MySql, database engine.

 PHP, programming language for building web sites.

There are countless others.