Distro no. 6: CentOS
Current version: 5.5
Code base: Red Hat Enterprise Linux
Supported hardware platforms: IA-32, x86-64, PowerPC, i386, s390, s390x
Number of users/downloads: Unavailable
CentOS 5.5 is built by a community of system and network admins, enterprise users, and Linux enthusiasts. Its low cost and attractive support options -- from forums to chat, wikis, and more -- set the distribution apart, according to Karanbir Singh of the CentOS Project.
Users familiar with Red Hat can benefit from the code base it shares with Red Hat Enterprise Linux, and several vendors now support the distribution. CentOS is geared toward "end users who already have some level of Linux awareness and are able to do basic levels of support in-house," Singh said. While the user community has concerns about aging applications included in the platform, Singh has an idea to address the problem: a community-driven stack adoption model, where users take ownership of the aging code.
For hardware support, CentOS relies heavily on upstream developments and works closely with vendors on code improvements. "Vendors and ISVs [independent software vendors] contribut[e] to the support community pool…as active community members, rarely -- if ever -- flying their corporate flag," Singh said. "Direct and unbiased cross-feedback [comes] from both ends of the user spectrum…Vendors are users too."