Windows 8 news continues to trickle from the Building Windows 8 blog at a steady clip: today, Gabe Aul detailed changes to the Windows 8 boot process that promise to drastically reduce startup times.

The team wanted to come up with a startup method that would deliver the benefits of a cold boot (a "fresh session" at startup, no power usage when off) while reducing the amount of time that it takes to load the operating system from disk to RAM. 

To accomplish this, Microsoft has combined aspects of a traditional Windows shutdown with system hibernation, which saves the contents of your RAM to disk and then restores it to RAM at next boot. While a Windows shutdown currently closes all user programs (the "user session") and then all system services and processes (the "kernel session") completely before powering off, Windows 8 closes the user session and saves the rest of your RAM's content to disk. The kernel session can then be restored to RAM quickly at next boot - this is more speedy than traditional hibernation both because there's less data to restore to RAM from the disk (just the kernel session, as opposed to the kernel session and the user session), and because restoring hibernation files is a fully multithreaded process in Windows 8. If the feature works as well as it does in the Microsoft demo video, it is indeed quite impressive.

Microsoft notes that drivers are still initialized during this startup process, which means that driver and system updates should no longer require a "full" reboot of the system (something Microsoft has been promising since the Longhorn days). However, for those of you more comfortable with a traditional "full" shutdown, there are command line options to toggle the new feature on and off ("powercfg /hibernate off" which has the unfortunate side-effect of completely disabling hibernation), and also to initiate one-time full shutdowns ("shutdown /s /full").

According to Microsoft, these improvements should benefit users with SSDs and HDDs alike, and will be especially noticeable when paired with systems supporting UEFI, the BIOS replacement that is slowly being adopted by most major PC manufacturers and motherboard makers. For full details, as always, you can check out the very detailed post on the Building Windows 8 blog.

Source: Building Windows 8 Blog

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  • iamezza - Friday, September 9, 2011 - link

    Yeah, it would be good if you could tweak how much space hibernation used or on what disk the hibernation file was stored.

    I recently upgraded to 8GB of RAM and found I had to completly disable hibernation because the hiberfil.sys was using 6GB of space of my 74.4GB (after format) SSD and I only had a few GB left free.
  • code65536 - Friday, September 9, 2011 - link

    You CAN tweak it. In an elevated command prompt in Vista or Windows 7, type "powercfg /h /?" for the details...
  • DanNeely - Friday, September 9, 2011 - link

    There's a way to change where the hibernation/swap files save to via control panel.

    IIRC it's under system-advanced, but I have hibernate turned off on this laptop because I don't have room after all the stuff I need for work.
  • name99 - Friday, September 9, 2011 - link

    For god's sake, can we please get this right?
    Your SSD is NOT "74.4GB (after format)".
    You bought a hard drive that was 80GB in size, NOT 80GiB in size. 80GB is approximately 74GiB. The manufacturer is correct; your OS is wrong.

    If your OS is so stupid that it doesn't properly understand the difference between a GB and a GiB, complain to the manufacturer. But don't spread stories about how "formatting used up almost 8% of the drive".
  • JNo - Friday, September 9, 2011 - link

    I concur. That would be another nice thing for them to change or give the option of in Win 8 - reporting disk space in GB instead of GiB

    Get to it MS!
  • titanmiller - Friday, September 9, 2011 - link

    Won't hibernation also cause additional wear on SSDs? I have an SSD in my Windows 7 box and hibernate it 1-2x per day. I have 12GB RAM so it tends to cause a lot of writing to the disk.
  • DanNeely - Friday, September 9, 2011 - link

    Unless you're running a DB server with a high load wear rates on SSDs are a non-issue.

    Assuming you have all 12GB of ram in use (empty pages won't be written), and your SSD is 120GB in size you'd create 36-72 extra wear cycles/year via hibernating. Current consumer level SSDs are good for a minimum of 3000 cycles, so you'd be adding 1 or 2% wear to the drive yearly.
  • JNo - Friday, September 9, 2011 - link

    Jesus, I have an SSD (80GB) and I don't worry about it. It's good for something like 20 years of write cycles at moderately high usage. Think how far HDDs have gotten in 20 years - from 30MB (my dad's 1st PC) to 2 TB! By the time your SSD wears out, there will be much faster, larger 100 petabyte holographic storage or something and you'll have ditched your SSD long ago.

    It's like driving a Ferrari at no more than 40mph to save on engine wear...
  • imaheadcase - Friday, September 9, 2011 - link

    I never understood why people cared about boot time.

    I've never heard a customer complain of that, in fact most people i know leave them on 24/7. lol
  • damianrobertjones - Friday, September 9, 2011 - link

    Fast boot time can and will equate to a faster pc in general.

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