What is the difference between Win2003 and UNIX server?
Microsoft Windows 2003 and Unix (of which there are many varieties, or flavors, including Linux, AIX, Solaris and more) are computer operating systems. Both Windows 2003 Server and quality Unix implementations are enterprise application servers that can be used for a variety of critical purposes, including, but not limited to, Web, email, and database hosting. Windows 2003 was developed by Microsoft and is, in many ways, the flagship of their software solutions.

UNIX's development roots begin about twenty years ago - jointly at Berkeley University and AT&T Bell Labs. UNIX is often referred to as an "open system", which means that its source code is publicly available. This has both its advantages and disadvantages. While it has allowed many thousands of developers from all over the world working for different companies to contribute to its development, it is also more complex and less coordinated.

Both of these operating systems make excellent platforms for mission-critical Web hosting, and they function well. There are some differences of the two systems:

Windows 2003 supports most Microsoft products including Microsoft FrontPage - a popular Web authoring tool.
Windows 2003 supports Active Server Pages (ASP) - a popular programming that allows you to build dynamically database-driven web pages (connecting to Microsoft Access or Microsoft SQL server).
Remote interactive access, via telnet or SSH is only supported under UNIX. Generally one is able to do more configuration/setup tasks themselves rather than having to request services from web hosts.
The majority of existing CGI programs (generally Perl scripts) that are available on the Internet have been developed on Unix platforms and hence tend to install and operate much more smoothly under Unix. Many Perl Scripts are FREE!

The bottom line is that for many web sites the operating system on which the Web server is housed is largely inconsequential. The real question is, "Are you using a specific web site or database technology that is more appropriately hosted on Windows 2003 instead of UNIX (or vice versa)?" If your web site does not require special features offered by Unix or Windows 2003, you can choose either Windows 2003 or Unix to serve your web site.