When looking for a Web hosting provider, one of the first things you often have to consider is what operating system the server will run. Now, this article is not about proving that one OS is better or worse than another, and if you already have a preference, then I recommend you stick with it. This article is not trying to convince you to change.
Several Operating Systems to Choose From
Linux is one of the more popular operating systems on the Web, mostly because it is so cheap to install and get up and running.
Macintosh hosting servers are very uncommon. In fact, if you want to host your site on a Macintosh server, you'll probably have to look into hosting it yourself.
Unix is very similar to Linux, but not as common on Web hosting services, usually because it is more expensive and the hardware is more specific.
Windows is another popular operating system for Web hosting providers because it has a lot of support.
Linux and Windows are the two most common and readily available operating systems, and there are many good reasons for using both. Unix systems are very similar to Linux (and Mac OSX systems are as well) but as I mentioned above, Macintosh systems are few and far-between.
Accessing the Server
The first difference that most people notice with Web hosting operating systems is how you access the server. Both Windows and Linux offer FTP access to your files, but only Linux will generally offer telnet or ssh access. (It's possible to set up telnet access on Windows, but very few hosting administrators offer it.) FTP is a way of transferring your files from your hard drive to your Web server. Telnet and SSH are a way to open a window directly on the Web server and manipulate files right there, usually using Unix command line commands.
Writing Your Pages
FrontPage extensions are often cited as the reason to use a Windows server. But there are Linux servers that offer this service as well.
CGI and Perl access are often found on both Windows and Linux servers, but it is more typical on Linux. If you need to program forms, you should make sure that your hosting service provides CGI or another way to process them.
Other Server-Side Scripts
But you're not stuck with just Perl if you need to process forms. Many hosting systems offer PHP, ASP, and ColdFusion. These server side scripting options give you a lot of flexibility. PHP is more often found on Linux systems, while ASP is more often found on Windows. ColdFusion can be found on both.
If you're going to run a dynamically driven Web site, then you'll want a database. The two most popular are mySQL and Access. mySQL runs on both Linux and Windows, but is more often found on Linux servers. Access is only available for Windows.
Security is very important to your Web host. Many people will argue that Windows servers have more vulnerabilities than Linux servers. But the reality is that they both have security problems. Security is more important at the hosting service's administration level than it is at the operating system level. If you have good administrators, your server will be more secure - regardless of OS.
The Bottom Line
The differences between the operating systems is much less than you might think. I would recommend, when choosing a hosting server you find one that has the options you want, rather than worrying about what operating system they are running on the back end.