Apache, the licence-free Unix web server, has been adopted by some 1.4 million new websites worldwide in the last month.
The gains coincide with the first alpha release of a new version of the operating system, called Apache 2, which has some new features including support for threads. These improve performance for applications.
Apache is now used at 7.9 million sites worldwide, compared with 6.5 million at the same point last month, according to the figures published today by UK-based internet consultant Netcraft.
Nearly all websites that use Apache run on a variety of Unix, with many users choosing to download Apache and install it on Linux - which could potentially cost nothing.
Mike Prettejohn, director of Netcraft, said: "Most Apache servers run on Unix. Linux is the most popular followed by Sun Microsystems' Solaris. Apache is the leading Unix server and Linux is becoming the most popular operating system on the internet."
Netcraft's survey received responses from more than 13 million sites. Pettejohn said the number of new sites shows that the "internet is getting bigger and bigger each month".
"Network Solutions [the domain name registration company] is allocating a new domain name every 1.5 seconds. In 1996 when we first started surveying use, there were 3000 certified sites. The web grew by more than 3000 certified sites last month alone. Ecommerce and hosting services are booming," he added.
Apache's share of the worldwide web server market grew from 58 per cent in February to 60 per cent this month. Microsoft's Internet Information Server (IIS) fell from around 22 per cent to 21 per cent, and third placed Netscape Enterprise Server held the number three spot with around seven per cent.
Pettejohn said the figures show that Microsoft is not doing as well as Apache in absolute terms. But the number of Windows 2000 sites, which comes with the latest release of IIS 5.0, has doubled.
"Windows 2000 grew from 20,000 sites to more than 40,000 sites during the month," he said. "There were more Windows 2000 sites on the internet than HP UX sites, and it has overtaken IBM's AIX in terms of number of internet websites."
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