Microsoft details Windows 8 'fast boot' feature

Microsoft's Gabe Aul has detailed modifications due in Windows 8 which, he claims, will drastically improve the time it takes your system to boot up - a critical feature for laptops and tablets.

In a thoroughly detailed post to the Building Windows 8 Blog, Aul explains how the boot, shutdown, and hibernate processes work in the current release of Windows 7, before detailing some of the key changes the Windows team has made to improve performance in Windows 8.

"As in Windows 7," Aul explains of a Windows 8 shutdown sequence, "we close the user sessions, but instead of closing the kernel session, we hibernate it. Compared to a full hibernate, which includes a lot of memory pages in use by apps, session 0 hibernation data is much smaller, which takes substantially less time to write to disk.

"Using this technique with boot gives us a significant advantage for boot times," Aul claims, "since reading the hiberfile in and reinitializing drivers is much faster on most systems - 30-70% faster on most systems we’ve tested."

A comparison graph provided by Aul show the potential advantage: by hibernating the kernel session, a large chunk of the startup process is removed and the amount of time required before the user can do anything with the system reduced accordingly.

The ability to start a system from 'cold' rapidly will be welcomed by laptop users, but there's another area in which Microsoft's work will be rewarded: tablet use. Owing to the relatively lightweight operating systems in use, most tablets on the market today boot remarkably quickly from cold - and spend most of their time in a warm-standby mode for instant-on usage.

If Microsoft truly wants Windows 8 to succeed on tablets - as rumours of a partnership with Samsung on devices for the BUILD conference next week suggest - then speeding up the boot and hibernate times will be key.

Despite its usage of partial hibernation, Aul claims that Windows 8 won't break the 'have you tried turning it off and back on again' troubleshooting beloved of techies across the land "Another important thing to note about Windows 8’s fast startup mode is that, while we don't do a full 'Plug & Play' enumeration of all drivers, we still do initialize drivers in this mode," he explains. "Those of you who like to cold boot in order to 'freshen up' drivers and devices will be glad to know that is still effective in this new mode, even if not an identical process to a cold boot."

For those who don't trust such wizardry to work first time, Aul describes an option in the Windows 8 user interface to revert to Windows 7-style shutdowns, while those looking for a one-off true cold-boot can use the '/full' switch on the shutdown.exe tool or pick 'Reboot' from the shutdown menu, which bypasses the fast boot technology.

Microsoft's 'Building Windows 8' blog is revealing some tantalising details about the company's next release, but has thus far kept quiet on the one issue that has everyone concerned: compatibility with standard Windows applications in the new ARM architecture build.