First of all, when choosing a host, it doesn't matter what kind of operating system you develop your web site on or what you use on your own computer. Web sites hosted on both UNIX and Windows servers are universally accessible because the data they serve is identical. The difference lies solely in the software used to serve that data.

In terms of reliability UNIX systems have a slight advantage. They are known to extremely stable and able to run for years without rebooting. Windows is also very reliable - slightly less so than UNIX but still able to handle the demands of modern web sites.

The majority of web hosts use various flavours of UNIX like Linux and FreeBSD. These operating systems are free and reduce the costs of a hosting operation. Windows costs thousands of dollars so some hosts charge extra for Windows accounts if they offer both types.

As well as being free, Linux and the other UNIX varieties are open-source software. Anyone can alter the source code and make improvements, updates, and additions. There is a large pool of dedicated enthusiasts who use their free time to work on this software. Windows, on the other hand, is Microsoft proprietary software so users are dependent on Microsoft to release updates. There is no way for an individual user to modify the code.

The main difference between the two types of operating systems is the type of software each can run. Windows is suitable for Microsoft products such as MS Access databases, ASP for delivering dynamic content, and VBScript for site enhancements. UNIX cannot accommodate these technologies so if you absolutely need ASP or VBScript you should pick a Windows host. UNIX hosts deliver dynamic content by using software such as PHP, CGI, and MySQL - technologies which are also available on Windows hosts.

Windows is necessary for hosting Windows media files such as videos and audio. Other types of media such as MP3, Flash, Shockwave and Real can be handled by either UNIX or Windows. Websites created in Microsoft FrontPage (a graphical HTML development package) can also be hosted on either type as long as MS databases or dynamic content are not included for use on a UNIX host.

Which is Best?

Before deciding which type of hosting to use for your website, consider carefully what kind of technologies you will need. Do you need a dynamic site? Will you have multimedia content such as streaming video or audio?

Both UNIX and Windows can provide dynamic content with PHP, MySQL, as well as CGI, and there are thousands of dynamic scripts readily available. Multimedia can also be hosted by either type of server, although Windows media (WMA and WMV) need to be hosted on a Windows server.

If you absolutely need Microsoft databases, ASP, and Windows media you have to go with a Windows host. Otherwise most websites are probably better off with a UNIX host. The advantages of UNIX over Windows include greater choices in web hosts, slightly better reliability, and (sometimes) cheaper hosting costs.