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I have a laptop - Lenovo T60.

When I close the lid, I see that the machine goes into suspended mode. The moment I open the lid, the laptop is instantly a live.

My concern - Does going into suspended mode make it safe to trasnport the computer - eg: travel on a bumpy road.

I ask because I'm not sure which parts shut off... For example, if the hard drive is still running, I'd say it's never safe to travel with the laptop in this mode.

I'd like some thoughts on this. Thanks!

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2 Answers 2

up vote 6 down vote accepted

Suspend writes the info to RAM (memory) & still uses power: drive(s), cpu and the moniter(s) are powered off.
The RAM modules are placed in self refresh mode and the CPU is powered off. The chipset is responsible for using the standby power to stay on enough to reactivate the main power supply when a button is pressed

and if you want to know what hibernate is:

Hibernate writes info to hard drive then powers laptop off.
Hibernate is resumed by pressing the power button.

So in terms of optimising battery life hibernate is better, but can take as much time as powering off, suspend is quicker but still uses power.

And in your question concerning hdd life. You should be able to drive over bumpy roads because the disk drive stops spinning.

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That was a good note... Then if the CPU is left on (while in suspend mode), what about the cooling? I don't see any fan nor do I notice any heat... –  itsols Nov 2 '12 at 14:15
    
woops, I mean:"the disk drive stops spinning, and the processor shuts down almost completely" –  Dr_Bunsen Nov 2 '12 at 14:18
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The CPU is entirely powered off in suspend –  psusi Nov 2 '12 at 14:18
    
@psusi really? I just read on multiple sites almost, because ram refreshments and to know when it has to power up again, and the last part makes much sense. –  Dr_Bunsen Nov 2 '12 at 14:20
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Yes, the DRAM modules are placed in self refresh mode and the CPU is powered off. The chipset is responsible for using the standby power to stay on enough to reactivate the main power supply when a button is pressed. –  psusi Nov 2 '12 at 15:08

pm-suspend

During suspend most devices are shutdown, and system state is saved in RAM. The system still requires power in this state. Most modern systems require 3 to 5 seconds to enter and leave suspend, and most laptops can stay in suspend mode for 1 to 3 days before exhausting their battery.

pm-hibernate

During hibernate the system is fully powered off, and system state is saved to disk. The system does not require power, and can stay in hibernate mode indefinitely. Most modern systems require 15 to 45 seconds to enter and leave hibernate, and entering and leaving hibernate takes longer when you have more memory.

pm-suspend-hybrid

Hybrid-suspend is the process where the system does everything it needs to hibernate, but suspends instead of shutting down. This means that your computer can wake up quicker than for normal hibernation if you do not run out of power, and you can resume even if you run out of power. s2both(8) is an hybrid-suspend implementation.

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OK, so there's suspend and suspend-hybrid. What is the default method used when we select suspend from the menu? –  itsols Nov 2 '12 at 16:33
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suspend...you lose your data if your battery runs out when in suspend... –  Anurag Nov 3 '12 at 5:02

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