UnixWorld: Comparing Apache and Internet Information Server

“A major difference between Apache and IIS is their prerequisites. While Apache is
available for many Unix versions, Linux, Windows and OS/2, IIS can run only in the
Windows environment. What’s more, the latest version of IIS will run only on Windows
2000 server.”

“Both IIS and Apache provide isolation between different Web client access requests.
Apache, in its current standard distribution, forks processes in response to incoming
Web client requests. This approach tends to be more resource-intensive than spawning
threads within a process, which is the approach adopted by IIS. However, thread
support will be one of the main enhancements to arrive with Apache 2.0.”
A major difference between Apache and IIS is their prerequisites. While Apache is
available for many Unix versions, Linux, Windows and OS/2, IIS can run only in the
Windows environment. What’s more, the latest version of IIS will run only on Windows
2000 server.

“… If you run a Windows-centric environment, and you prefer the service and support
offered by Microsoft, your natural choice should be IIS. If you run a cost-conscious,
heterogeneous environment, and you have a staff with Web server expertise, your
natural choice should be Apache.”