warning about sleep mode on MB and MBP

[Ombligo]

Our Mac IT head just sent this out.. may interest some here -

I have been reading some interesting and slightly disturbing posts about SafeSleep mode and how it can hose your drive.
http://www.silvermac.com/2006/how-to...ro-hard-drive/

Here's a quote from that article and I would think the same thing applies to MacBooks:

This is what Apple’s MBP manual states:

Warning: Wait a few seconds until the white sleep indicator light on the display latch starts pulsating (indicating that the computer is in sleep and the hard disk has stopped spinning) before you move your MacBook Pro. Moving your computer while the hard disk is spinning can damage the hard disk, causing loss of data or the inability to start up from the hard disk.

[Ombligo]

Bad link.. here is the post:

How to save your MacBook Pro hard drive
Wed, 15 November 2006

Isn’t it beautiful when using your MacBook / MacBook Pro, you just close the
lid and the computer instantly goes into the sleep mode? Even better, you
just open it and in a few seconds you are where you were before.

And the coolest of all is when you’re in a hurry, you just shut the lid, put
the computer into the bag and run downstairs, or jump on your bike and off
you go. Right ?

Wrong!

What I just described above is a big no-no if you have a MacBook, MacBook
Pro or the very last model PowerBook (late 2005).

The reason for this is SafeSleep, a technology Apple introduced to all
portable computers since October 2005.

What happens when ‘normal’ computers are put into sleep mode is that the
memory is supplied with a very small amount of power to keep its content
‘alive’. When you wake up the computer, it will be in the state you left it
before. But in case of a power failure, or battery going completely flat,
the memory will lose the power and therefore your data is gone. Game over.

Apple’s SafeSleep works similar to this but it has something else for when
the disaster strikes. When you close the lid the computer goes to sleep
mode, but not instantly. Firstly, it copies entire content of its memory
onto the hard drive, and then goes to normal sleep mode. Once you wake up
the computer, the memory is already loaded and you can use it straight away.

If you lost the power/battery, once you power on the computer again, the
memory content that was stored onto the hard disk will be loaded, so you
take it from where you left it before. You will see the black and white
screen while this is happening, so don’t panic, your display is just fine.

And this is exactly where the problem is. You must not move your computer
while the data is written to the hard drive. You have to wait until the
sleep light on the front starts pulsing. This may take anything between 10
and 30 seconds, depends on the amount of memory you have installed in your
computer.

This is what Apple’s MBP manual states:

Warning: Wait a few seconds until the white sleep indicator light on the
display latch starts pulsating (indicating that the computer is in sleep and
the hard disk has stopped spinning) before you move your MacBook Pro. Moving
your computer while the hard disk is spinning can damage the hard disk,
causing loss of data or the inability to start up from the hard disk.

So, you wonder - what difference does it make, Apple notebooks have the
Sudden Motion Sensor and will prevent any data loss or disk damage ?

Wrong again! The Sudden Motion Sensor has no effect in this situation, so
you’ll be better off to leave your computer to finish the job it has to do.

[robfilms]

o-

thanks for the info

be well

rob
mbp 2.4 prev version

[deckeda]

I'd like to hear more evidence about this. At work people walk around "all the time" with their PBs and MBPs open, like waiters holding a dinner tray.

Don't know why exactly, but maybe it's because they're only going a short distance and don't want to have to wait for sleep/unsleep.

Presumably, these laptops aren't writing much to their HDs during the move, but they are moving around with spinning HDs.

Maybe there's something different about a HD's actuating arm moving back and forth (such as during an big, active write) that makes it want to slam into something if the HD is bounced around?

[M A V I C]

[quote deckeda]Maybe there's something different about a HD's actuating arm moving back and forth (such as during an big, active write) that makes it want to slam into something if the HD is bounced around?
Yes. When the drive is off, it parks the arm.

This really is no danger with the sleep mode, just people mishandling the laptop while the drive is still moving. The problem can occur if the machine is going to sleep or if it's awake.

I also have to wonder how hard they are slamming the MB around to make this happen.

[Jem]

This is interesting...

I have been very disappointed in what I see as erratic behavior of my 2.2 Ghz MBP when it comes to putting it to sleep, waking it up, or even moving it.

I am now wondering if some of the strangeness in its behavior is related to these new "features".

I have problems with:

A. The MBP taking a long time to go to sleep (where the LCD powers off and the hard drive spins down)
B. Often difficulty waking the laptop up... with the LCD not coming on. Sometimes opening and closing the lid a few times wakes it up, other times it requires a force reboot via the power key.
C. When *moving* my MBP, it will "wake up" while closed (LCD and hard drive) and then will presumable go back to sleep after 5 to 10 seconds... although once it DID not and I later found a VERY hot MBP in my laptop case.

Ironically, my 900 Mhz G3 iBook was MUCH more robust in terms of doing what it should *when* it should WRT going to sleep and waking up. By comparison, my MBP seems very "high maintenance" and does not instill the same peace of mind I had with my iBook.

If this "new" technology is partially to blame, I wish there would be a way to turn it off.

I can do without the "paranoid" backup technologies if it will just work reliably in the ways it always has before.

Anyone else have experiences like mine with their MBP?

[M A V I C]

A. Yes, that's "safe sleep" for ya. I've got 4GB of RAM, takes a while to write that to the HD.
B. Sometimes this happens if I open the machine before it has gone to sleep. Sometimes it happens if I unplug a USB device from the MBP after I've put the lid down, or if I plug one in before I open the lid.

How full is your HD?

You can always set the sleep to function like your iBook did. You just wont have the session saved if you let the battery die.
http://www.macworld.com/article/53471/20...pmode.html

[Acer]

I have problem "B." on my MBP 2.2 (prev gen). About 50% of the time, when I open the sleeping 'book, I hear the CD drive do its thing, the sleep light goes out, but the display remains blank. It's not a backlight thing, there is simply nothing there.

It seems to happen more often when I have left the book asleep for a few hours than say 5 minutes, but it has happened after 5 min, too.

I have taken to pressing the power key multiple times (not holding it for reboot, juts enough to make the dialog pop up), and that seems to eventually wake it up, but it can be a 20-30 second or longer wait.

[Jem]

MAVIC,

Your are the man! I will give this a try (turning OFF safesleep) and see if that makes things a bit more consistent.

And Acer, your experience sounds almost identical to mine. Sometimes weird combinations of keys (or the power key) work, sometimes unplugging and plugging the power cord, and sometimes nothing works (cap locks won't turn on or off). Will give the suggestion in MAVIC's link a try to see if that improves things...

[ADent]

The new MB and MBP don't the accel sensors that stop the drive?

Or are they ignoring it during the Safe Sleep write (which is possible since you have to step out of the OS to write the whole thing to disk)?