Comments on: Safe Sleep Nonsense http://anoved.net/2007/08/safe-sleep-nonsense/ Wed, 16 May 2012 12:48:05 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Jim http://anoved.net/2007/08/safe-sleep-nonsense/#comment-39 Jim Sat, 18 Aug 2007 15:47:00 +0000 http://anoved.net/2007/08/safe-sleep-nonsense/#comment-39 From the TidBITS article: <i>"But Apple's documentation warns you that when you put such a laptop to sleep (by closing the lid, for example), you must not move it until the power light has begun pulsating."</i><br/><br/>For what it's worth, during the year prior to this episode I've often handled my MacBook immediately after shutting the lid, either to carry it around, to put it in its bag, or simply to set it aside if I was using it on my lap. Surely it was still writing the contents of RAM to disk in some (if not many) of these innumerable cases, but I've never experienced any trouble with the drive or sleep recovery as a result of these routine motions.<br/><br/>Consequently, in practice the machine seems to sleep instantly, even if it does not technically enter a fully asleep state for some period after shutting the lid. Nevertheless, I concede that in this matter I've been lucky, not that I'm right. From the TidBITS article: “But Apple’s documentation warns you that when you put such a laptop to sleep (by closing the lid, for example), you must not move it until the power light has begun pulsating.”

For what it’s worth, during the year prior to this episode I’ve often handled my MacBook immediately after shutting the lid, either to carry it around, to put it in its bag, or simply to set it aside if I was using it on my lap. Surely it was still writing the contents of RAM to disk in some (if not many) of these innumerable cases, but I’ve never experienced any trouble with the drive or sleep recovery as a result of these routine motions.

Consequently, in practice the machine seems to sleep instantly, even if it does not technically enter a fully asleep state for some period after shutting the lid. Nevertheless, I concede that in this matter I’ve been lucky, not that I’m right.

]]> By: Jim http://anoved.net/2007/08/safe-sleep-nonsense/#comment-38 Jim Sat, 04 Aug 2007 18:10:00 +0000 http://anoved.net/2007/08/safe-sleep-nonsense/#comment-38 I think you are correct. I have since observed the LED more carefully and realized that it does glow constantly for a period before beginning to pulse. Removing the battery during this time does require a full restart.<br/><br/>My attempted refutation was the result of the simple test I did immediately after reading the original article. However, my confidence in the success of that trial was misplaced as it was clearly not a comprehensive test.<br/><br/>It was fun recording the snarky video, though. I think you are correct. I have since observed the LED more carefully and realized that it does glow constantly for a period before beginning to pulse. Removing the battery during this time does require a full restart.

My attempted refutation was the result of the simple test I did immediately after reading the original article. However, my confidence in the success of that trial was misplaced as it was clearly not a comprehensive test.

It was fun recording the snarky video, though.

]]> By: Ian http://anoved.net/2007/08/safe-sleep-nonsense/#comment-37 Ian Sat, 04 Aug 2007 15:01:00 +0000 http://anoved.net/2007/08/safe-sleep-nonsense/#comment-37 In replicating your experiment with Safe Sleep, I came to a few conclusions. The first conclusion is that Safe Sleep is probably a good idea for casual users, since it acts quickly under light load conditions and is a generally unobtrusive way to avoid calamity. Second, a bit of trial and error with prematurely shutting my Macbook off led to the knowledge that the white LED on the front edge of the computer glows brightly for the duration of the time that the contents of the RAM are being written to the hard drive. This was borne out when my physical memory was loaded all the way up with a variety of applications and a virtual operating system; the time needed for a successful Safe Sleep and return to operation was roughly 15-20 seconds. Any less time prior to removing the battery and the computer required a full restart and all data was lost. When the same experiment was conducted with no applications running, and most of my memory free, Safe Sleep engaged within the time needed to remove the battery. From this experience, I think it is reasonable to assume that your belief that the amount of RAM utilized, as opposed to installed, is the determining factor in Safe Sleep speed of operation is accurate. For the record, my computer is a 2.0GHz Macbook with 1.5GB RAM, running 10.4.10. It also restarts if the lid is slammed too hard. Good old sudden motion sensor. In replicating your experiment with Safe Sleep, I came to a few conclusions. The first conclusion is that Safe Sleep is probably a good idea for casual users, since it acts quickly under light load conditions and is a generally unobtrusive way to avoid calamity. Second, a bit of trial and error with prematurely shutting my Macbook off led to the knowledge that the white LED on the front edge of the computer glows brightly for the duration of the time that the contents of the RAM are being written to the hard drive. This was borne out when my physical memory was loaded all the way up with a variety of applications and a virtual operating system; the time needed for a successful Safe Sleep and return to operation was roughly 15-20 seconds. Any less time prior to removing the battery and the computer required a full restart and all data was lost. When the same experiment was conducted with no applications running, and most of my memory free, Safe Sleep engaged within the time needed to remove the battery. From this experience, I think it is reasonable to assume that your belief that the amount of RAM utilized, as opposed to installed, is the determining factor in Safe Sleep speed of operation is accurate. For the record, my computer is a 2.0GHz Macbook with 1.5GB RAM, running 10.4.10. It also restarts if the lid is slammed too hard. Good old sudden motion sensor.

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