Transporting MBP: Sleep, Hibernation and dangers to hard disk

Question

I used to transport my MBP by closing the lid and putting it in my backpack. Recently, however, it started to overheat when I do that. At first I thought it was some bug, maybe it hadn't gone to sleep properly. But then it happened again. I started to manually putting it to sleep before closing the lid, but no luck. It happened again. It happened 3 or 4 times in about 2 months and then the computer stopped working properly and I had to take it to professionals. They said I should NEVER put it in my backpack in sleep mode. Maybe if it's a 5min trip only, but not otherwise. They said the hard disk is not completely shut off in this mode and so carrying it around in movement may damage it. They checked my computer and said that indeed it was a hard disk problem, and that now that it was changed it's working fine. They said I should always shut it down before transporting it, which is a pain. (I live in Rio and it's above 30ºC most of the year, maybe that contributes to these heating problems, don't know…)
What annoys me is that I haven't found any official statement about it by Apple. I know people who never turn it off and even I did it without any problem for years with my previous MBP (well, in fact it died one day out of the blue and I have no clue why). Actually I can only assume based on discussions that the computer actually goes to sleep mode when I shut the lid, and I can only speculate about what this actually means because I haven't found any official information regarding it. I found that there's a mode called "hibernationmode 25" which is supposed to be essencially the same as shutting down the computer and saving the current RAM data to the hard disk. But I haven't found any official statement confirming this. I don't know if it really is as safe to carry it shut down as in this mode. Does anybody know where I can find official information about this? Or if there's any reliable way to contact Apple itself and actually get a reply?
Thanks!

Answer 1

The Expert, Professional, you spoke to has NO clue. When any computer is put to Sleep, irrespective of what OS is installed (OS X or Windows) and what version of that OS, the only part that is supposed to be kept alive is the RAM and even that will go to sleep and dump it's contents onto the hard drive after an extended period of time if the system also has the hibernation mode set to do so. It then goes into a Deep Sleep state basically turning off completely.
I suspect what you are seeing it the system is trying to go from standard sleep mode to the Deep Sleep Hibernate mode and when that happens it must partially wake up to write the RAM data to the hard drive. At that point your system is not going back into either sleep mode or the Deep Sleep mode and that is when it heats up.
There are also many reports of Mac's of all ages crashing when trying to wake up from sleep and most of the time this is after it has gone into the Deep Sleep state and when you try to wake it the system doesn't or can't put back into the RAM the data that was written to the hard drive causing the system to hang and force a hard shutdown and restart.
I personally solve that problem by turning off the Hibernate system and deleting the Sleep Image file that is used to store the RAM data. So my MBP never going into that Deep Sleep state and I have never had a problem waking it whether after a few minutes or a day or so of being asleep. And it has never woken up on its own in my computer bag.
But to answer your question, statement from that Professional, the hard drive turns off completely when the system is put to sleep.