Introduction
Many of us working in the radiation protection area use a range of computer software packages to help with our day-to-day work. While the cost of computer hardware has dropped dramatically over recent years, propriety software has remained relatively expensive due to the lack of competition. The purchase price of software for your new laptop can be more than the cost of the laptop.

 Fortunately, there is a community of software developers out there known as the “Open Source” movement who believe in sharing their work and in developing good quality alternatives to the propriety programs we are used to.

This ARPS website for example runs with the help of several OpenSource applications - the operating system is Linux, the web server is Apache, the database is MySQL, the programming language is PHP and the application is Drupal. 

I will attempt to give an overview some of the more popular and useful programs available, that can replace many common propriety programs used in business and radiation protection. Most of these programs described below are able to run on the Windows, Mac OS X and Linux operating systems.

The following headings list the proprietary program followed by a free open source alternative.

Internet Explorer to Mozilla Firefox

Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite, managed by the Mozilla Corporation. Firefox had 20.78% of the recorded usage share of web browsers as of November 2008, making it the second-most popular browser in current use worldwide, after Internet Explorer.

To display web pages, Firefox uses the Gecko layout engine, which implements some current web standards plus a few features which are intended to anticipate likely additions to the standards.

Firefox includes tabbed browsing, a spell checker, incremental find, live book marking, a download manager, and an integrated search system that uses the user's desired search engine. Functions can be added through add-ons created by third-party developers.
http://www.mozilla.com/en-US/firefox/

Microsoft Office to OpenOffice
Word to Write
Excel to Calc
PowerPoint to Impress
Access to Base

OpenOffice is the leading open-source office software suite for word processing, spreadsheets, presentations, graphics, databases and more. It is available in many languages and works on all common computers. It stores all your data in an international open standard format and can also read and write files from other common office software packages. It can be downloaded and used completely free of charge for any purpose.

 It is an like to like  replacement for Ms Word, Excel, PowerPoint, and Access, and is able to open and save documents in the above formats. http://www.openoffice.org/

Microsoft Visio to Dia

Dia is free software/open source general-purpose diagramming software. It has a modular design with several shape packages available for different needs: flowchart, network diagrams, circuit diagrams, etc. It does not restrict symbols and connectors from various categories from being placed together.

Dia can be used to draw many different kinds of diagrams. http://live.gnome.org/Dia
 
Photoshop to GIMP

GIMP is a free raster graphics editor used to process digital graphics and photographs. Typical uses include creating graphics and logos, resizing and cropping photos, altering colours, combining multiple images, removing unwanted image features, and converting between different image formats.

GIMP can also be used to create basic animated images in GIF format. It is often used as a free software replacement for Adobe Photoshop, the most widely used bitmap editor in the printing and graphics industries; however, it is not designed to be a Photoshop clone.
http://www.gimp.org/
 
Microsoft Publisher to Scribus

Scribus is a desktop publishing (DTP) application. It is designed for flexible layout and typesetting, and the ability to prepare files for professional quality image setting equipment. It can also create animated and interactive PDF presentations and forms. Example uses include writing small newspapers, brochures, newsletters, posters and books.
http://www.scribus.net/

Microsoft Word to LyX  (for creating Scientific publications and papers)

LyX is a document processor following the self-coined "what you see is what you mean" paradigm (WYSIWYM), as opposed to the WYSIWYG ideas used by word processors. This means that the user only has to care about the structure and content of the text, while the formatting is done by LaTeX, an advanced typesetting system.

LyX is designed for authors who want professional output with a minimum of effort and without becoming specialists in typesetting. The job of typesetting is done mostly by the computer, following a predefined set of rules called a style, and not by the author. Specific knowledge of the LaTeX document processing system is not necessary but may improve editing with LyX significantly for specialist purposes.

Although LyX is popular among technical authors and scientists for its advanced mathematical modes, it is increasingly used by social scientists and humanists for its excellent bibliographic database integration and ability to manage multiple files. LyX has become especially popular among self-publishers because LyX combines the ease of use of a word processor with the typesetting abilities of LaTeX.

LyX is for people who want their writing to look great, right out of the box. No more endless tinkering with formatting details, “finger painting” font attributes or futzing around with page boundaries. You just write. On screen, LyX looks like any word processor; its printed output — or richly cross-referenced PDF, just as readily produced — looks like nothing else.
http://www.lyx.org/Home
 
Adobe Illustrator to Inkscape

Inkscape is a free and open source vector graphics editor application similar to Illustrator, CorelDraw, or Xara X. Its stated goal is to become a powerful graphic tool while being fully compliant with the XML, SVG and CSS standards.

It supports many advanced SVG features (markers, clones, alpha blending, etc.) and great care is taken in designing a streamlined interface. It is very easy to edit nodes, perform complex path operations, trace bitmaps and much more.
http://www.inkscape.org/

SPSS statistical package to R

The R programming language, sometimes described as GNU S, is a programming language and software environment for statistical computing and graphics.

R is widely used for statistical software development and data analysis. R provides a wide variety of statistical (linear and nonlinear modelling, classical statistical tests, time-series analysis, classification, clustering, and others) and graphical techniques.

Can be used as an Addin with MS Excel, MS Access and OO Calc.
http://www.r-project.org/

Vista to Linux

Linux is a Unix-like computer operating system family based on the Linux kernel. Linux is one of the most prominent examples of free and open source software development; typically all the underlying source code can be used, freely modified, and redistributed by anyone under the terms of the GNU GPL license. 

Linux distributions are predominantly known for their use in servers, although they are installed on a wide variety of computer hardware, ranging from embedded devices and mobile phones to supercomputers, and their popularity as a desktop/laptop operating system has been growing lately due to the rise of netbooks and the Ubuntu distribution of the operating system.
http://www.ubuntu.com/

Portable Document Format (PDF) is the de facto standard for the secure and reliable distribution and exchange of electronic documents and forms around the world.  CutePDF Writer (formerly CutePDF Printer) is the free version of commercial PDF creation software. CutePDF Writer installs itself as a "printer subsystem". This enables virtually any Windows applications (must be able to print) to create professional quality PDF documents - with just a push of a button!
 
FREE for commercial and non-commercial use!  No watermarks!  No Popup Web Ads!

(Note with Linux, saving documents to PDFs is standard equipment)

go to Cutepdf

Links to other alternative software
OSALT.COM
Top 100 of the best (useful) OpenSource Applications
Software Equivalents
SourceForge repository