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sleep mode

Message #1 - Posted 2004/01/21 - David Yeh

What exactly happens in sleep mode in OS X? Does it mean _zero_ activity? No cron scripts, no synchronizing the system clock with a hardware server, no software update checking? Does it also mean the computer and all servers it is running is _completely_ inaccessible from the outside (by me or a potential hacker)?

Just looking for a precise definition.

Thanks,
dave

Message #2 - Posted 2004/01/21 - Gregory Weston

Previously, David Yeh wrote:

What exactly happens in sleep mode in OS X? Does it mean _zero_ activity? No cron scripts, no synchronizing the system clock with a hardware server, no software update checking? Does it also mean the computer and all servers it is running is _completely_ inaccessible from the outside (by me or a potential hacker)?

Depends on the machine, but almost all (or maybe now it really is all) machines on which OS X is supported go way-way-way asleep when they're told to sleep. So deep that you can hot-swap PCI cards because the bus isn't actually hot. (It's not supported and it's a phenomenally stupid thing to do for kicks, but it has been confirmed to work at least on a couple models.) Nothing is running except possibly an OpenFirmware timer that's waiting to wake the machine up.

G

Message #3 - Posted 2004/01/20 - Tom Stiller

Previously, Gregory Weston wrote:

Previously, David Yeh wrote:

What exactly happens in sleep mode in OS X? Does it mean _zero_ activity? No cron scripts, no synchronizing the system clock with a hardware server, no software update checking? Does it also mean the computer and all servers it is running is _completely_ inaccessible from the outside (by me or a potential hacker)?

Depends on the machine, but almost all (or maybe now it really is all) machines on which OS X is supported go way-way-way asleep when they're told to sleep. So deep that you can hot-swap PCI cards because the bus isn't actually hot. (It's not supported and it's a phenomenally stupid thing to do for kicks, but it has been confirmed to work at least on a couple models.) Nothing is running except possibly an OpenFirmware timer that's waiting to wake the machine up.

G

And many models of ethernet interface which can respond to the Wake-On-LAN feature.

Tom Stiller

PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
7BDA 71ED 6496 99C0 C7CF

Message #4 - Posted 2004/01/21 - Neill Massello

David Yeh wrote:

What exactly happens in sleep mode in OS X? Does it mean _zero_ activity? No cron scripts, no synchronizing the system clock with a hardware server, no software update checking? Does it also mean the computer and all servers it is running is _completely_ inaccessible from the outside (by me or a potential hacker)?

Just looking for a precise definition.

In deep sleep, memory is refreshed, but the CPU is halted and no processing occurs. The PMU (Power Management Unit) and hardware clock run, and the USB controller monitors for key presses. Depending on your Energy Saver settings, the Ethernet controller may be monitoring for wake-up ("magic") packets sent to its hardware (MAC) address, and the internal modem may be monitoring for telephone rings. The AirPort card is turned off.

To gain access to anything on your Mac, a network hacker would first have to wake it from deep sleep. If your Mac is not set to wake for Ethernet access, this couldn't be done. Otherwise, it would have to be done from your local network: AFAIK, magic packets are not routed.

Message #5 - Posted 2004/01/24 - David Yeh

Neill Massello wrote:

In deep sleep, memory is refreshed, but the CPU is halted and no processing occurs. The PMU (Power Management Unit) and hardware clock run, and the USB controller monitors for key presses. Depending on your

Thanks, this is what I wanted to know.
On a side note, my dad just mentioned to me that sometimes when he is near his computer (flat-panel iMac) when it is asleep and sets of a static charge (by touching something metal in the same room or a piece of clothing or something), the Mac will sometimes awake from sleep. How odd. How anyone else experienced this and does anyone know why it happens?

-dave

Message #6 - Posted 2004/01/24 - Neill Massello

David Yeh wrote:

On a side note, my dad just mentioned to me that sometimes when he is near his computer (flat-panel iMac) when it is asleep and sets of a static charge (by touching something metal in the same room or a piece of clothing or something), the Mac will sometimes awake from sleep. How odd. How anyone else experienced this and does anyone know why it happens?

It has happened to me several times. I suspect it's the static discharge creating some slight disturbance -- electrical noise -- on the USB bus. Just unplugging a USB device will usually wake a sleeping Mac.

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