Microsoft has revealed that its Windows 8 operating system will feature a fast startup mode.
Gabe Aul, director of program management in Windows, explains over on the Building Windows 8 blog:
The key thing to remember though is that in a traditional shutdown, we close all of the user sessions, and in the kernel session we close services and devices to prepare for a complete shutdown.
Now here’s the key difference for Windows 8: as in Windows 7, 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. If you’re not familiar with hibernation, we’re effectively saving the system state and memory contents to a file on disk (hiberfil.sys) and then reading that back in on resume and restoring contents back to memory. Using this technique with boot gives us a significant advantage for boot times, since reading the hiberfile in and reinitializing drivers is much faster on most systems (30-70% faster on most systems we’ve tested).
Microsoft also offers up some data showing how much faster this mode is compared to a normal cold boot:
Microsoft is pulling this trick off by dumping the BIOS and instead going with UEFI (Unified Extensible Firmware Interface):
One thing you’ll notice in the video was how fast the POST handoff to Windows occurred. Systems that are built using Unified Extensible Firmware Interface (UEFI) are more likely to achieve very fast pre-boot times when compared to those with traditional BIOS. This isn’t because UEFI is inherently faster, but because UEFI writers starting from scratch are more able to optimize their implementation rather than building upon a BIOS implementation that may be many years old. The good news is that most system and motherboard manufacturers have begun to implement UEFI, so these kinds of fast startup times will be more prevalent for new systems.
Here it is in action ... it's very fast:
The notebook used in that video is an EliteBook 8640p (Intel Core i7-2620M, 8GB, 160GB SSD).