CentOS7 vs centos6

The CentOS Project has announced general availability of CentOS-7, the first release of the free Linux distro based on the source code for Red Hat Enterprise Linux (RHEL) 7.

It's also the first major CentOS release to ship since the CentOS Project entered into a new funding and co-development partnership with Red Hat in January.

Because CentOS-7 is built from the freely available RHEL 7 source code tree, its feature set closely mirrors that of Red Hat's latest OS, which shipped in June after a six-month beta period.

"CentOS conforms fully with Red Hat's redistribution policy and aims to have full functional compatibility with the upstream product," the OS release notes explain. "CentOS mainly changes packages to remove Red Hat's branding and artwork."

Like RHEL 7, CentOS-7 is now powered by version 3.10.0 of the Linux kernel, with advanced support for Linux Containers and XFS as the default file system. It's also the first version of CentOS to include the systemd management engine, the firewalld dynamic firewall system, and the GRUB2 boot loader.

The default Java Development Kit has been upgraded to OpenJDK-7, and the system now ships with Open VMWare Tools and 3D graphics drivers out of the box.

Also like RHEL 7, this is the first version of CentOS that claims to offer an in-place upgrade path. Eventually, users will be able to migrate from CentOS-6.5 to CentOS-7 without reformatting their systems – but unfortunately, the tools needed to achieve this are still being tested and won't be made available until a later date.

For this release, the CentOS team launched a new build process, in which the entire distro is built from code hosted at the CentOS Project's own Git repository. Source code packages (SRPMs) are created as a side-effect of the build cycle, however, and will be hosted on the main CentOS download serversalongside the corresponding binary packages.

"For the CentOS-7 build and release process we adopted a very open process," CentOS contributor Karanbir Singh said in a mailing list post announcing the release. "The output of the entire buildsystem is made available, as it's built, at http://buildlogs.centos.org/ – we hope to continue with that process for the life of CentOS-7, and attempt bringing CentOS-5 and CentOS-6 builds into the same system."

Disc images of CentOS-7 – including separate builds for the Gnome and KDE desktops, a live CD image, and a network-installable version – are available beginning on Monday from the main CentOSdownload site and via BitTorrent.

Plans are underway to also make the OS available in other forms in the near future, including Docker images; images for major cloud vendors, including Amazon, Google, HP, and RackSpace; images for use with on-premises cloud platforms such as OpenStack and Eucalyptus; and possibly an image for doing a minimal install.

Its been long that i have heard that CentOS 6.5 kernel (2009) is "Too Old" as compared to CentOS 7 kernel (2013). ... Upgrade Centos to 6.5 not 6.6 ?

Between the two varieties of CentOS there are five significant differences. Here’s what CentOS 7 adds:

• Docker support, for using containers
• systemd, the controversial init replacement
• Performance Co-Pilot, a set of real-time frameworks and services for recording and monitoring system performance
• OpenLMI, a standard remote application programming interface (API)
• XFS as the default file system

If you’re moving from a CentOS 6 server to CentOS 7, be aware that there’s no easy way to migrate to XFS from other Linux file systems, such as ext4 or btrfs. Instead, the best path is to back up and restore the server.

Unless you need one of CentOS 7’s new features, stick with CentOS 6. It has a long, proven track record.

By "too old" is probably meant that it is too old. It Linux 2 6 32went live on Dec 3rd 2009. This is more then 5 years now. Windows 7 OS was launched in that year and Mac OS X Snow Leopard was a new thing in that year.  The kernel developers do support new devices, new gadgets and new architectures, but they do it within the up to date kernel. The distro developers has to backport the new things into the old kernel, if they want to support them.
So first of all it means that by using 3.10 they do not have backport that much and also they are on the same architecture base as the kernel head developers. In the benchmarks herehttp://www.phoronix.com/scan.php...
it seems that in most parameters the later kernels are same or a bit better. In some areas like graphic display performance they are quite better and they look more predictable in the performance.
If your device is fully supported by 2.6 kernels, you can be quite fine, because security fixes seems to be still available see the updates here - The Linux Kernel Archives. If you have some newer stuff or you just want to choose the easy way for your desktop than 3.10 looks like a better choice. On the other side a an ordinary desktop user, you probably do not care.