Blog Post

NetBoot and the Air


Since I heard that the MacBook Air didn’t come with an onboard optical drive, but did come, instead, with this magic virtual disk feature, I’ve been having a very interesting wonder – does this also mean that NetBoot now works – at least for the Air – over wireless?

And, fresh off the show floor today hot from MacFixIt, is confirmation that this is in fact true. On these machines, at least, NetBoot will work over a wireless network.

Before I start talking about the implications of this, some quick background on NetBoot, especially for those who’ve never used this. NetBoot is a nifty little tool that lets you create an image of your boot disc, and then mount it remotely on client machines to install it. This requires four things to work: a Mac running some flavor of OS X Server and three processes – NetBoot, afp, and DHCP, a separate network-compatibly Mac, a network cable, and a bit of patience. (The cable is now evidently superfluous.)

Drop the install DVD into the Server machine, fire up Image Utility, and create your NetBoot image. (This is cake; like many Apple utilities, it fairly well walks you through using it.) Set up your server to host the image, and you’re done with it. Now go to the client machine. Hold down N during boot to cause the client to look for network images, and you’re good to go.

Because of the need for Server, and because creating an image and installing it takes longer than simply installing it on the client machine directly, you mostly see multi-machine administrator types doing this. The really nifty thing about NetBoot is, in creating this image, you can customize the settings in your image – and then allow access to this install disk to all the machines you want to use it.

Network capable machines can also run as normal off these disks; and you can also set your client machines to always preferentially boot from the NetBoot server, so that every time they reboot, they use the same clean image. (This is very useful in the context of large public or semi-public groups of computers – think campus computer labs – where you’d rather users not be meddling with settings.) Each individual copy of Server can manage up to 25 different NetBoot images, so you could even theoretically install specific setups on groups of machines. I’ve also seen it used to install Tiger from DVD’s on non-DV-bearing computers.

So that’s NetBoot. Provided your NetBoot image host doesn’t go splort – and believe me, if you have machines booting every day over the network, you live in terror of that – it’s a very, very shiny little trick. But back to the MacBook Air, and doing it wirelessly.

Remote Disc evidently contains a NetBoot server, which is in itself interesting. But even more so is that it can be done wirelessly, which must have involved some major changes to EFI, especially in regards to how EFI handles wireless networks. Scuttlebutt is that this will even work on secured wireless networks. That is really interesting. (Working enterprise Mac support has taught me that if there is one thing you can’t depend on with Intel Macs, it’s their ability to find or connect to a given wireless network, especially an exncrypted one.)

Smoothing those issues out would help all of us – maybe there’s another EFI update in the works for Intel Macs?

5 Responses to “NetBoot and the Air”

  1. Stephanie Guertin

    @joe – No, sadly, I don’t. We have a ridiculous amount of trouble with that kind of thing, and may I say, Apple, if you’re listening, you’re totally shooting yourself in the foot with this.
    There’s no logic to which machines will talk to which routers and protocols, either. It’s ridiculous that I can have two machines, same hardware, unboxed on the same day and set up from the same install disk image, and one of them will talk to the brand-new Linksys router and one won’t. Very frustrating. Best of luck with yours, and be sure, if I ever figure out a trick, it’ll immediately be up here. :)

  2. Joe Bruno

    Yes, why is it that every other computer I have connects seamlessly to my Netgear router with WPA, lovely high signal strength, whereas every so often the iMac goes through a period of disconnection and repeated timeouts when I try to re-join the network… then starts behaving perfectly again and continues working perfectly for days?

    Working with enterprise support, do you have any suggestions?

    It’s a bit humiliating when the Asus Eee can be relied upon to connect every time and the iMac can’t!