How does "Find My Mac" actually work?

yawns

macrumors member
Original poster
Oct 12, 2011
87
4
I've tried Googling this but can only find articles about how to use the service. What I'm wondering is how the iCloud's "Find My Mac," actually locates your computer? With phones it seems easy because they're connected to cell towers and have GPS. MacBooks don't do GPS, so how can the service locate the device? MAC geolocation is totally unreliable, and IP geolocation is imprecise at best. I'm just not understanding how the service could consistently locate anything.
 

wrinkster22

macrumors 68030
Jun 11, 2011
2,623
6
Toronto
how do iPod touches and wifi iPads do it? wifi. it does not work if the mac is not connected to a wireless network
 

mkrishnan

Moderator emeritus
Jan 9, 2004
29,776
12
Grand Rapids, MI, USA
My impression is that it uses the same wifi-based location system (Skyhook type of thing) that the original iPhone used. It works by checking the wifi signals the computer can see against a database of wifi signals whose locations are known.

If you used an original iPhone, you know it works pretty well, actually, in urban areas where there are lots of wifi signals. If there are no wifi signals or the wifi is not on, my understanding is that it doesn't work at all.
 

WarpSpawn

macrumors member
May 30, 2011
93
0
Maybe it depends on how ISPs do things in your specific country but I think you might find that location based in IP address is more precise than you might think. It is never going to be a replacement for GPS but with both my shiny new MBP and my iPad 2, it consistently pins it down to the row of houses I live on. Though I cannot say as I have had the chance to try it at any other addresses as yet.
 

yawns

macrumors member
Original poster
Oct 12, 2011
87
4
My impression is that it uses the same wifi-based location system (Skyhook type of thing) that the original iPhone used. It works by checking the wifi signals the computer can see against a database of wifi signals whose locations are known.

If you used an original iPhone, you know it works pretty well, actually, in urban areas where there are lots of wifi signals. If there are no wifi signals or the wifi is not on, my understanding is that it doesn't work at all.
Thanks for the tip. I guess the service uses Skyhook. From what I've read, Skyhook uses the network's MAC address in conjunction with MAC addresses of other wireless networks in range. That way, even if the network you're connected to isn't in Skyhook's database, if the people next door and across the street are, they can still take a pretty good guess at where you're at. I don't know if signal strength is sent up, as well, but if yes, they can probably use that to increase accuracy, too.

Skyhook apparently collects most of its information by constantly wardriving the planet. I think iPhones also phone home to Skyhook when they connect to wireless networks, reporting the MAC, SSID, and GPS coordinates of the network. (Incidentally, Google does the same thing with Street View drivers and Android phones.)
 

mkrishnan

Moderator emeritus
Jan 9, 2004
29,776
12
Grand Rapids, MI, USA
Skyhook apparently collects most of its information by constantly wardriving the planet. I think iPhones also phone home to Skyhook when they connect to wireless networks, reporting the MAC, SSID, and GPS coordinates of the network. (Incidentally, Google does the same thing with Street View drivers and Android phones.)
Yes, people have raised ethical issues with this. (And occasionally, it leads to buggy behavior, like picking up some wifi signal that's not where it's supposed to be, and then having Maps shift to the other side of town), but FWIW on the whole it worked pretty well on the original iPhone, and in the places where it works, it ought to work pretty well for a mac also.
 
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