The Kernel Column with Jon Masters
Linus Torvalds announced the release of the 3.5 kernel in time for last month’s issue, and with it the opening of the merge window for 3.6. The merge window is the period of time during which Linus takes source code patches (modifications) that are more disruptive in nature than simple bug fixes. It is during this time that major new features are merged, following a complete test cycle (eg the entire life of 3.5) in the linux-next and staging (in the case of new drivers only) trees.
During the 3.6 merge window, Linus pulled in a number of cool new features, including ‘suspend to both’, which is a feature that writes out a hibernation disk image at the same time as suspending to RAM. It is a feature that has existed on other operating systems (such as Apple’s OS X) for some time and it is the reason (for example) that a Mac which has run low on battery during suspend is still able to resume successfully. Resuming from disk is of course slower than resuming from RAM, but it is a nice fallback in the case that a laptop or mobile device’s battery drains completely during the period that it is suspended.