CentOS: Red Hat Enterprise Linux, Minus Red Hat - page 3
Getting Something For NothingThe nice thing about Linux is that the distinctions between servers, desktops, and workstations are mainly package selections and kernel configurations. The "enterprise" Linuxes usually have slower release cycles, longer support cycles, and paid tech support. For some folks it's worth paying to have someone to commiserate with when the system melts down on a holiday weekend. (And help fix it.) But under the hood all the same code is available to anyone. Unlike that Other OS, a user can start with a free or inexpensive Linux, and then completely customize it to suit. CentOS is suited for the tuff do-it-yourselfer who wants enterprise features enabled out of the box, and doesn't need a lot of handholding. CentOS has some community support options, such as IRC and online forums. There is also some commercial support available from independent companies, but this is still limited.
Supported architectures are fewer than your run-of-the mill Linux distribution, which will run on anything if you work at it hard enough. CentOS supports only x86 and x86_64 (AMD64 and EMT64T. For those of you who have not been keeping up with advances in 64-bit CPUs, EM64T is Intel's implementation of AMD64. Yes, you heard me rightly- Intel followed AMD.) RHEL AS officially supports more: Itanium2, AMD64, and EM64T, plus all x86, IBM zSeries servers, IBM POWER Series, and IBM S/39. But not RISC, Sparc, PowerPC, m68k, Alpha, or any of the other hundred-and-one computing architectures that Linux fans like to force poor old Linux to run on.