Hibernate (and Sleep)

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I running Win7 on my accer laptop (64 bit I think).

I used to turn the computer off each night, and then start up new again each morning. I found that it was taking a fairly long time to shut off sometimes, and it was taking a fairly long time to boot up.

I decided to try “hibernate” overnight, or when I am away from the computer for any length of time. Wow, it turns off quickly, and it turns on quickly. All I have to do in the morning is enter my password, and its ready to go,…. None of the ‘not responding messages’ I used to get when trying to connect with my gmail accts using Firefox. Since I am usually plugged into a power supply, i have also removed the battery when using it at home.

So my questions are;
1) What danger am I subjecting myself to by leaving the computer in ‘hibernate mode’?
2) What exactly is hibernate mode??
3) What is, or what difference is there with ‘sleep mode’?

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Beiland,

Sleep basically just throttles down the power to the various parts of the computer. Hibernate on the other hand takes a snapshot of your current contents of working memory to your hard drive then shuts down the computer. When you restart in the mourning instead of booting windows it just restores the memory contents from the file and off you go right where you left off. The danger of hibernate is if the hibernation file gets corrupted it’s a bear to recover from. Personally I’ve disabled hibernate on all my computers (as well as fast boot). YMMV. HTH :cheers:

May the Forces of good computing be with you!

RG

PowerShell & VBA Rule!
Computer Specs

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I use hibernate on both machines and have never had an issue. About the only time I reboot is post MS updates. (I really like the fast start/stop, especially on my desktop with SSD.)

cheers, Paul

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I like to use hibernation if I’m going to be away from the computer for less than 5-10 hrs. otherwise I’ll shut down.
Sleep mode, when set to sleep for a specific time, just seems too buggy to me imo.

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I just came back from a week in France and the machine fired up no problems – except the email backlog.

cheers, Paul

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As RG has pointed out, there is the danger of Hibernation file corruption, but some have found they were unable to reconnect to the Internet when waking up a laptop – at least.

The theory behind this is that the machine retains the IP address which can then cause a conflict if/when DHCP issues it with another one.

I always shutdown and switch off at the wall when done and as this laptop takes 60 – 65 secs to boot up from cold, that isn’t a problem although Norton 360 can be a pain at times to fire up as if it’s Definitions are out of date, they need updating before it will allow me to browse – but that is something I can live with.

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In response to your questions:

1) What danger am I subjecting myself to by leaving the computer in ‘hibernate mode’?

I’ve found hibernate to be relatively safe. Unlike sleep mode, your computer is truly off in hibernate. A sleeping laptop, disconnected from power, can trickle discharge itself to zero battery and force a hard (as in improper) shutdown–neither the OS nor the applications get a chance to close themselves normally.

However that doesn’t really answer your question. The risks are, in no particular order of importance:

– the memory state file is really big, as big as the installed RAM on your computer. These days that means in the range of 1 – 16 GB, roughly speaking. It could fill all free space on the hard drive, though that’s not usually a problem on modern hard drives. If you only had a smallish SSD drive though, and lots of data already on it, maybe that might be an issue?

– hard drive errors are a particular hazard to the memory state file. If the drive corrupts this file and did not detect that corruption, you’d have an unreliable system when it wakes out of hibernation. If the drive detects the corruption (a more likely scenario), then the system would fail to come out of hibernation and force a cold start. This would be equivalent to a BSOD in it’s effects because the OS runtime image and all the running applications would not have had a chance to shut down normally (the write to the memory state file does not count);

– one thing to remember. Windows needs to shut down and restart, fully, from time to time. And in particular after software installs and many kinds of system changes. Even if Windows allows the install or change without prompting for a restart! Waking from hibernation does not do this, but it is easy be lulled into thinking that it does. After all, the physical act of shutting down and starting up looks like a system restart. And the prompts telling you that it’s a hibernation shutdown or startup don’t really make that point.

2) What exactly is hibernate mode??

The contents of RAM are written out to a special file, then the computer shuts off. When the system restarts it checks for this file. If the last shutdown was a hibernation shutdown, then Windows uses the memory state file to reload RAM. The theory is that after waking from hibernation RAM is exactly where it left off, so the computer is ready to run. Everything is as you left it.

In reality things can be a little more challenging. I run this way and computer’s configuration can change slightly. In a laptop, external devices and services can change their state or availability. This most commonly touches external mice, keyboards, monitors and networks.

All that said, hibernation still works and works amazingly well. I’ve found some glitches to be sure. On my system, plugging in an external monitor sometimes causes the system to fail to restart properly (a laptop finding). On my desktop, I’ve had external mice and keyboards fail to initialize properly. Recovering from the first forces a complete reboot. Recovering from the second simply requires the USB device to be unplugged and inserted again. Neither causes any secondary problems.

However note this. I’m careful to only enter hibernation after shutting down all my applications. It’s something I do to protect myself.

3) What is, or what difference is there with ‘sleep mode’?

As I’ve stated, hibernation is a quick restart system that allows the computer to turn off 100%. Sleep modes are also quick restart systems, but only turn the computer off by 99% or so. With Sleep, power continues to trickle to the CPU and the RAM banks are likewise kept running. The hard drives may or may not be kept running, but for maximum power savings the drives must be turned off. The screen is turned down or off.

Restarting from sleep can be a bit disconcerting. I’ve found that the system generally wakes up quickly except for the drives (my comments mostly apply to mechanical drive systems). The hard drives take much longer than any part of the system to wake up and the system, though it appears to be ready to run, really is not. So you start clicking away and nothing happens. For 5, 10, 15 seconds or more! And there’s nothing on the user interface to tell you what is happening. On older systems if you pay attention you can hear the hard drives spinning up to operational speed.

Now with SSDs becoming commonplace, the latency caused by mechanical hard drives in sleep mode should be much less. However lots of systems with an SSD still have a mechanical hard drive too.

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However note this. I’m careful to only enter hibernation after shutting down all my applications. It’s something I do to protect myself.

The whole point of hibernation/sleep is to resume from exactly where you left off, running apps, modified documents etc. You may as well shut down instead of hibernate.

cheers, Paul

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“…restart in the mourning…” — RetiredGeek
That is precisely how I feel several times a month, when posting/booting/starting up Windows, a time for mourning.
In times of Windows troubles!, RG’s wording is an apple of gold on a platter of silver. 🙂 🙂

"Take care of thy backups and thy restores shall take care of thee." Ben Franklin, revisted

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….So my questions are;
1) What danger am I subjecting myself to by leaving the computer in ‘hibernate mode’?
3) What is, or what difference is there with ‘sleep mode’?

2 and 3 first: Sleep mode stores a snapshot of the last state of your computer in RAM before powering down. Volatile RAM. So it is virtually instantaneous in turning on and off. But a loss of power to the PC loses the last state image and you have to cold boot and reload your open apps, etc.

Hibernate does the same thing only stores this image on a storage drive (usually C: drive). So restoring the system may be a bit longer, but still way faster than a cold boot. And a power loss does not effect restoring from the image on boot (reboot).

1. The only “danger” is your system could develop a brief stability issue eventually as your present system state is always saved and reestablished upon returning to your computer. Eventually an instability may occur, be carried along and cause the system to behave other than expected. On a modern system this could be many weeks of operating in hibernate or sleep mode before you notice something odd about your system’s behavior. Saving any open work, shutting down apps and then doing a restart (warm boot) should set everything aright again so no big deal for all the time it saved you in booting.

Many people operate routinely from a sleep mode or hibernate. I often recommend it for people who complain about boot times. There really is no reason to routinely shut down a PC anymore as it uses essentially as much power “off” as asleep (powered down).

Truth though, I shut down at night. Since I fire up the PC first thing in the morning between getting my caffeine ready and socks and shoes on the PC is running and waiting for me when I sit down. Sleep mode the rest of the time. I never hibernate because I usually never leave anything open that hasn’t saved itself before I walk away from the PC. But I could just as easily operate out of sleep mode or hibernate mode until I felt the system developed an issue.

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I use hybernate at school as an “ad hoc.” i.e., I’m moving the laptop to another classroom, and wish to continue right where I left off within 2-3 programs such as FF & Google. Other than that, I shut down at the end of day every day.

"Take care of thy backups and thy restores shall take care of thee." Ben Franklin, revisted

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My work pattern, which I only hold to rather loosely, is to hibernate on weekdays and perform full shutdowns on weekends. This accomplishes the goal of periodically giving Windows a full restart on a regular basis.

The whole point of hibernation/sleep is to resume from exactly where you left off, running apps, modified documents etc. You may as well shut down instead of hibernate.

This is a matter where you have to calibrate your risk tolerance. As I said, I’ve encountered a semi-predictable scenario wherein attaching an external monitor to a laptop, between active sessions, can cause the laptop to refuse to boot. This forces a hard restart. If I left applications open, and files open in those applications, I risk damaging those files. That’s too much risk for me.

The primary benefit of a hibernation restart isn’t in saving an application state. It is the abbreviated Windows start, with fewer logscripts/GPO/security/indexing/update/inventory scans. App start times are trivial in comparison.

The Windows 8 hybrid shutdown feature is an indication of this as well.

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