Counting Linux users is no easy task since there is typically no requirement for users to register their installations. Yet Linux distributions do try and count users in an attempt to quantify their user base and relative footprint in the operating systems space.
Red Hat's Fedora community Linux distribution has now tallied its user base, and it's a number that on the surface would make it the largest installed base of any Linux distribution, with at least 9.5 million users and possibly as many as 10.5 million. Fedora competitor Ubuntu Linux currently claims to have 8 million users.
"The total number of users has always been an incredibly difficult number to measure," Paul Frields, Fedora's project leader, told InternetNews.com. "If you total up all the unique IP's ... on Fedora 7, 8 and 9, it adds up to about 9.5 million boxes right now."
Frields noted, however, that Fedora's methodology may not tell the whole story. Since the Fedora Core 6 release, the project has counted usage based on the number of unique IP addresses that check Fedora for updates.
The counting methodology has the potential to overcount the same machine if the box has a dynamic IP address -- for instance, using Dynamic Host Configuration Protocol, or DHCP (define) -- that could change over time.
At the same time, the current counting methodology could also be leaving out a significant number of machines: A single unique IP address could be in front of many physical machines, with each background system getting a local IP via Network Address Translation, or NAT (define), and local network DHCP.
"So for everyone hopping addresses, there are probably some machines we're not counting because they are all coming from a single IP address," Frields said.
The 9.5 million figure is spread across three separate Fedora releases, each of which shows different numbers. Frields tallied the numbers to be accurate as of Nov. 19th. Fedora 7 has nearly 3.4 million IPs, Fedora 8 release in has 3.9 million IPs, and the Fedora 9 release has nearly 1.8 million. Additionally, Fedora's Rawhide release, which is its always-in-development build, reported nearly 500,000 unique IPs.
Frields also noted that he is still seeing over a million Fedora Core 6 machines poll for updates, even though it is no longer an actively updated distribution. Fedora Core 6 was released in October 2006, and by March 2007, was reporting over 2 million active unique IPs.
Frields' Fedora tally also does not include users of Red Hat Enterprise Linux, which is Red Hat's commercial subscription offering. In a recent analyst event, Red Hat executive vice president Paul Cormier said in a presentation that the company currently has over 2.5 million paid subscriptions for its Red Hat Enterprise Linux offerings.
As a result, Frields agreed that the total Red Hat family of Linux distributions could exceed 13 million users.