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Comment by seanalltogether | Hacker News Reader

"Internet Recovery. Help is everywhere.

If your Mac problem is a little less common — your hard drive has failed or you’ve installed a hard drive without OS X, for example — Internet Recovery takes over automatically. It downloads and starts Lion Recovery directly from Apple servers over a broadband Internet connection. And your Mac has access to the same Lion Recovery features online. Internet Recovery is built into every newly-released Mac starting with the Mac mini and MacBook Air."

Anyone wanna guess how that mechanism works? Micro kernel on some internal flash memory?

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I'd imagine Internet Recovery is simply an EFI application stored in the Mac's firmware, and that the app itself is an extension of the pre-existing NetBoot/NetInstall concept that supports http and does some machine and dmg verification.

Not sure how this one works, but Macs have had a thing called NetBoot[1] for quite a while which does almost exactly what Apple is describing now.

[1]: http://en.wikipedia.org/wiki/NetBoot

I haven't used this myself, but the Macbook Air has always been able to boot from a remote DVD drive straight from EFI.

http://reviews.cnet.com/8301-13727_7-10329287-263.html?tag=m...

Perhaps this works in a similar way?

It must be something small like that, nothing stored on the HD. I wonder if it pulls down enough to create a recovery partition and then boots into that?

Lot's of info in John Siracusa's exhaustive review on page 2:

http://arstechnica.com/apple/reviews/2011/07/mac-os-x-10-7.a...

That's the standard recovery partition, but you'll still need a working hard drive to boot from that.

Internet Recovery doesn't even require a working hard drive, so it's an entirely different system.

It probably works the same way that WANboot works on Sun/Oracle SPARC machines:

http://download.oracle.com/docs/cd/E19683-01/817-5768/wanboo...

There's just enough code to initialize the network interface/s, grab an IP, and download a file from an HTTP/S server. Once the file is downloaded, it's executed and you have the beginnings of a bootstrap procedure for your OS installer.

WANbooting has been around for almost ten years now, so the idea isn't that new.

This was probably even technically possible with PowerPC machines, as they used OpenBoot firmware just like Sun SPARC machines did. I guess they wrote the EFI code necessary to do the same thing.

"...or you’ve installed a hard drive without OS X, for example — Internet Recovery takes over automatically"

Could a dual boot system (Lion + Ubuntu) be confused with "hard drive without OS X" and be taken over by the Lion Recovery automatically?

Hope this doesn't means that only OS X should be installed in a Mac.

I doubt it, since Boot Camp is a native OS X feature.

Boot Camp only allows for one other OS. Back when I tri-booted, I had to do it all manually (and use refit). Boot Camp had no idea what was going on.

I'd imagine they're targeting more the situation of "I bought a new, blank hard drive".

It's Apple, so I would assume... fairies?

I'm not sure if this is anything different from the Recovery partition that Lion installs on all Macs. If it's the same thing, there's basically just a small partition with a very minimal OS X install that you can boot into if your main system is hosed to reinstall the system software from Apple's servers.

I'm not sure who's down-voting you, but your answer is correct. It is indeed the recovery partition. It includes a compressed lion system tree with Safari.

it should not: "your hard drive has failed or you’ve installed a hard drive without OS X, for example ". I know apple is deceiving, but I can't guess how they would install a recovery partition a new "drive without osx".

Ah, thank you for calling my attention to that. I had somehow read it to mean "If your boot partition is hosed."

It is not. The page states it works with a blank drive. It is built into the EFI firmware.

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