main page   Information briefs • macos x server • macos x (client) • darwin • netboot   Installation reports • PHP 3 • PHP 4 (Zend) • MySQL • Python (coming soon)   Special Reports • Apple Media Event 10/99 new iMacs and MacOS 9 • 1999 wwdc keynote • Quick and Dirty MacOS X Server Installaion Guide   Articles   News Archive • 1999 • 1998 • RhapNet (coming soon)   Advertising info   Contact Us   About Us   Links   The Tweak List			NetBooting In short, NetBooting allows any properly-equipped Apple-branded Macintosh computer to boot up off of a network server instead of its own resident hard drive. NetBooting is not a new concept in computing, but it most definitely a new concept in the Apple universe. What this allows is not only tremendous flexibility, but ease of administration and use, a combination not found in too many computing implementations. Introduced by Steve Jobs at MacWorld San Francisco '99, NetBooting will be an important piece in Apple's drive to win back educational, workgroup, and SOHO clients.   What hardware can be used? Because of the very specifically engineered process, only those Macintosh computers with the proper OpenFirmware can utilize NetBooting. Currently, the only machines which can be NetBooted are iMacs and the Blue-and-White PowerMacintosh G3 lines. Any model made in the future will be NetBootable. The other side of the NetBooting process is MacOS X Server. Because of MacOS X Server's hardware requirements, you can only use a PowerMacintosh G3 computer for the server in a supported configuration. Apple will not support NetBooting processes on non-PowerMac G3 servers.

 

			How does it work? Well, it's kind of complicated, so we'll break it down: OpenFirmware is responsible for a number of tasks during the startup process of any PCI-bus PowerMacintosh computer. Not only does it help to identify and load drivers for ADB, SCSI, HFS, HFS+, and more, newer versions of OpenFirmware have the necessary features to utilize networks, especially BootP. BootP is short for the "Bootstrapping Protocol." The BootP, as you can see in the graphic above, is one of the three protocols a Macintosh can use use connect to and retrieve a dynamically assigned IP address from. When you hold down the 'N' key during the strartup process on an iMac or a Blue-and-White G3, your computer searches your physical Ethernet network for a BootP server. Upon finding the BootP server, an IP address and AFP login is assigned to the NetBooting computer. This accomplished, the computer now has all the necessary prerequisite network-related information it needs. When it's ready, the NetBoot computer searches for…a NetBoot server.   Back at the ranch, uh, NetBoot server, there are disk images (of the same kind created and used by DiskCopy) resident on the hard drive. When a NetBoot client looks to boot up from the server, the NetBoot server sends the system folder on this disk image to the client computer over the network using tftp, which is a related but less-reliable mechanism than TCP/IP. Not all of the operating system is loaded at the initial transfer of the system folder - just most. When the necessary amount of the system folder has loaded, a screen comes up prompting the user on the client machine for a username and password. The username and password are used to: authenticate the user as a legitimate system user load the personal preferences of the user from the server to the client machine load the personal volume(s) of the user from the server to the client machine Once a user logs in, the computer can be used just as if it were a standalone machine with it's own hard drive. The personal volumes loaded by the NetBooting process are actually just network volumes shared over the network between client and server machines via AppleShare-ish services.

 

			What are the catches? What kind of networking will we need? Well, need as a minimum and need as a practical matter are two different things. At a minimum, you will need a 10-Base-T network, though a 100-Base-T network is recommended. What you will find is that depending on your network's topology, and your network's wiring, and the boot-up patterns of the NetBoot clients, you may have cases in which booting takes a long time, or files are shared slower, or that there is a general slowdown in the networking in your environment. Why? Well, the answer is simply bandwidth. If you have multiple clients booting at once, then you will have a lot of information being transferred along the network. You could (and will) easily saturate the bandwidth during the startup process. After the booting process, however, you will still have to contend with other network traffic (Windows, file transfer, other) on the network. This traffic, however, is of a general, and not a specifically NetBoot, concern.  What is MacManager then? MacManager is, essentially, the replacement in the new MacOS X world replacement for the old At Ease. For those of you unfamiliar with that software, At Ease is a piece of Apple-branded software which allows administrators to lock down or free up individual MacOS computers for use in a variety of environs, including offices, schools, and more. Password based, and very tough to hack, At Ease became one of Apple's heralded security-based products. With the switch to MacOS X, Apple is pushing the technology used in their products (and the way they all work) in a different direction, and so old solutions like At Ease are being phased out. But since this sort of functionality is both applauded and required by certain segment of the educational market, Apple has been working on creating new solutions for the MacOS X platform. MacManager is this beast. It's not entirely the same, and there are still many functions to be added and GUI's to be tweaked, but it should be a powerful At Ease replacement come time of the release of MacOS X. It is backward compatible with all 68040 and higher Macintosh computers, including all PowerMacs. We will be adding more information on MacManager and how it interacts with clients at a later point when we have the ability to review its functionality in person.

 

			We will be adding considerably to this information brief in the coming weeks. Not only will we bring you more detailed and easy-to-understand information on NetBooting and its processes, but also a look at how to configure this new and power ful feature. Thanks to Eric Carr for pointing out a couple of mistakes!

 

			Current Time: March 13, 2010 • 6:08 PM EST

 

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