If you want to work on web operations, Apache and Tomcat are useful skills
What is it?
Apache is not just the leading open source HTTP web server, it also has more than twice as many users as Microsoft IIS (Internet Information Services). It is free for anybody to download, provided they meet the licence terms. Nevertheless, Apache is bundled with many commercial server products, and it is supported by most suppliers.
Tomcat is a free, open source implementation of Sun's Java Servlets and Java Server Pages. It comes from the Apache Foundation's Jakarta project, which supplies pure Java tools, including the Struts web application development framework.
Where did it originate?
Apache was created in 1995 at the National Centre for Supercomputing Applications (NCSA), University of Illinois. It was put together from patches for the old NCSA HTTP Sever, which Apache later superseded - hence "a patchy server".
When the Apache Software Foundation was formed in 1999, Sun handed over its Servlet container code and put its project effort - including teams of paid developers - behind Tomcat, which is Sun's official Servlet container reference implementation.
What's it for?
Apache is a highly configurable web server, which can be customised or extended with third-party modules. Tomcat can also function as a web server, or be integrated with other web servers, including Microsoft IIS.
What makes it special?
Apache is free, has the largest installed body of users of any web server, and is supported by a worldwide army of developers.
The authors of the Wrox Guide, Professional Apache Tomcat, said, "Apache has a reputation of being much more secure than Microsoft IIS. When new vulnerabilities are discovered in either server, the Apache developers fix Apache far faster than Microsoft fixes IIS."
Being Sun Microsystems' reference implementation means Tomcat needs to be 100% Servlet and JSP-compliant.
How difficult is it to master?
On the one hand there is a huge amount of helpful material available free on the internet; on the other, there is a great deal of moaning about the absence of newcomer-friendly documentation for these and other open source products. Neither Apache or Tomcat are for beginners.
Where is it used?
As of early September 2004, according to the , Apache was the server of choice for 67.7% of websites, with Microsoft IIS at 21.21%, and Sun and Zeus at low single figures and declining. Apache and Microsoft have retained roughly the same market shares since November 2003, despite the number of websites growing at about one million a month.
What systems does it run on?
Downloads of Apache are available for about 30 different operating systems, including Linux, Unix, mainframes and Windows.
Not many people know that...
At least 40 different open source licences are in use, each of which has slightly different terms. Most do not include a warranty.
What's coming up?
The majority of releases of Tomcat and Apache are bug fixes. Since they are not driven by licence revenue, major upgrades are infrequent.
Rates of pay
Apache is now so ubiquitous that it is impossible to give a meaningful salary range. Java developers with Tomcat skills can look for £35,000 and upwards.
The Apache Foundation home page is the place to start your search for free tutorials. Alternatively, authoritative guide books are available from O'Reilly and Wrox.
How many sites run on Apache?
Sample size 53,341,867 websites
Source: Netcraft Web Server Survey