Web Design Whim

OK, you have a laptop/notebook/netbook.  You close the lid and the screen goes off, you press the power button and the machine shuts down, but what’s actually happening here?  Let me explain what each does.

If you Shut Down your PC, windows sends a signal to every program running to prompt to save the data and then close down, Windows itself then closes all of it’s active files, and sends the shutdown message to the PC to turn itself off.  when you power on from a shutdown state, this is called a cold boot, all files are freshly loaded, the memory starts from blank, your machine will be as good as it’s ever going to be after a cold boot.

Sleep is a state where every window you have open, every file that you are working on is kept in memory, the display is powered off, but power still runs to your cpu, your memory and some other parts of your machine.  If you’ve read my PC guide, you’ll know that RAM is non permanat storage, so when it’s not receiving power it’s wiped clean. this is why the power is kept to your RAM.  when you power the machine up from a Sleep state it will appear ready almost instantly.  But remember your machine’s ram has not been reset so if you have any memory that hasn’t been fully cleared from programs you were running, it will be in the same state it was previously.

Hibernation is where your computer takes everything you have in RAM, all programs, data, every single window you have open and their locations etc, and copies the entire lot onto the hard drive and then shuts down.  When you power back on, it copies it all back from the hard disk to RAM so Windows loads back to where it was.

So what are they for then?  Well, Sleep is for when you’re just leaving the machine for a few minutes, and want to preserve some battery life,  Hibernate is when you’re away from the computer a long time, it means your PC won’t use any battery power at all.  Hibernate takes less time to boot than booting after shutting down does.  Most notebooks that are about to run out of battery will automatically hibernate when there’s only a small amount of battery left to give you a chance of keeping any unsaved files.  But the problem with Hibernation is that the file that’s copied onto your hard disk may become corrupted.  If that happens, you’ve lost whatever you were working on.  So hibernation is good to use, but remember to save your work.  And shutting down your machine is the best way to keep it clear of memory hogging programs and temporary files cluttering up your hard drive.

What to use is up to you,  but remember the drawbacks, sleep still uses battery, hibernate may fail and you end up losing what your working on, and shut down, the slowest yet most reliable of the 3….

If you have any questions feel free to mail me on zygomorphic@webdesignwhim.com

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