NetBoot

NetBoot is a technology from Apple that enables New World ROM Macs to boot from a network.

A disk image with a copy of Mac OS X, Mac OS 9, or Mac OS 8 is stored on a server (typically Mac OS X Server). Clients receive this image across a network using many popular protocols including but not limited to: HTTPS, AFP, TFTP, NFS, and Multicast ASR. Server-side NetBoot image can boot entire machines, although NetBoot is more commonly used for operating system and software deployment, somewhat similar to Norton Ghost.

To NetBoot a client machine, hold the "N" key as the Mac boots, or select the NetBoot server using the Startup Disk preference pane (or control panel in OS 9). Alternatively, New World Macs can be started with the Command (⌘), Option (⌥), O and F keys pressed to enter the Open Firmware prompt. Note that on a PC keyboard this is Windows, LAlt, O and F. Once in the Open Firmware one can tell the client to attempt then NetBoot procedure by entering 'boot enet:0' and pressing the return key.

Mac OS 8.5 and Mac OS 9 use only BOOTP/DHCP to get IP information, followed by a TFTP transfer of the Mac OS ROM file. Next, two volumes are mounted via AppleTalk over TCP on which the client disk images reside. All in all, the Classic Mac OS uses three images; a System image which contains the operating system itself, but may also contain applications. Next a private image (or scratch disk) is mounted in an overlay over the read-only System image. Finally, an applications image is mounted. This image, however, may be empty.

The transition to Intel processors has not affected NetBoot. Both Intel and PowerPC-based servers can serve images for Intel and PowerPC-based clients.

NetBoot was first announced as a part of Mac OS X Server 1.0 at the Macworld Conference & Expo on January 5, 1999.

NetBoot is a derived work from the BOOTP protocol. Sun, Linux, and IBM’s RS/6000 have been using this for some time now.

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