Without web servers, we would never have websites and the web would not exist. While the machines are a variation on the PC theme, it is the software that does the job is what I want to highlight here. Microsoft’s Internet Information Server (IIS) would be an example of a proprietary option but what I want to mention are its open source alternatives and it is these that largely dominate the market because they will work on operating systems like Linux or BSD UNIX.
Apache is more than just a web server because it is a whole collection of software projects that have their own open source licences, which are more permissive than GPL (GNU Public Licence). One of these is HTTPD (HyperText Transport Protocol Daemon) and it is that which gains the Apache name here. My impression is that it was the first of series of projects that now includes OpenOffice among their number as well as Tomcat, which is a Java server page platform that sounds as if it is based on HTTPD. There also is a story that the Apache name came from the nickname of “a patchy server” but I cannot confirm the truth of that.
Nginx (pronounced Engine X) is a more recent upstart that has grown in favour because of its different way of handling multiple processes at the time. It appears to support the same technologies as Apache HTTPD and I have had a go with it on a VirtualBox virtual machine running CentOS. So far, that has not got so far but this experiment is set to continue. Notable users include WordPress.com and Fasthosts so it certainly is gaining acceptance. The perceived robustness of performance is the driver for that though some websites that I have are not great demonstrations with more outages experienced than is ideal, one I have running on Apache appears to have less downtime. The offline server that I have appears to exert a greater load on a system than Apache too but this needs further investigation because it may be caused by a sub-optimal set-up due to a lack of experience on my part.