Zero Admin? That’s old hat!
- 28 June, 1997 22:00
The Wintel marketing machine may have appropriated the term Zero Administration but savvy network managers have had zero administration for years thanks to a little-known technology – BootROMs.
A BootROM is a piece of firmware which slots into the network card to enable the PC to boot up to a server.
Long before the Gartner Group published its report on PC support costs, and years before the eruption of the network computer-NetPC debate – in fact, in 1991 – Auckland University’s school of engineering began using BootROMs to centrally administer a PC network. More recently it brought its Linux network under the same scheme.
The school’s electrical engineering department has 150 PCs (ranging from 486-33MHz machines to Pentium 200s) which are used daily by around 600 students and staff. Each is fitted with a BootROM from Accton, D-Link or 3Com.
All student PCs have hard drives (because some applications need up to 8Mb to run or students may be working on large data files and therefore need the hard drive) but these are wiped either daily or weekly.
The PC network has three Novell Netware 4.1 servers (a 486, a Pentium and a Pentium Pro) with Windows 3.11 running from the server.
Linux is used particularly for technical applications. When users log on to the Linux network, the operating system is downloaded and runs locally. If, for example, users have older machines (486s, for example) they can connect to the server and run Linux applications via X-Windows (a Windows-like GUI designed to run over the network).
Users can log on to either network and use any machine to get to their desktop. There are different boot files for differently configured PCs held on the server.
Technical manager Dayl Brack says booting machines from the servers and running applications across the network (which is switched Ethernet) doesn’t have a great impact on the network in terms of traffic or speed. The servers need a lot of storage (2Gb of Windows applications and 10Gb of file storage) but disk is cheap, he says. This is off-set against having to load 2Gb of applications on every PC.
In his view the main benefit, reduced administration and support, outweighs any drawback. Plus users can’t inflict damage on hardware.
“In the worst-case scenario you can always reformat the hard drive and reboot,” he says.
“The load imposed on the network by remote booting is not a problem - you’re getting a 1Mb file maybe, once or twice a day from each machine. Neither is the load of running applications across the network a problem.
“I think it was difficult to set up in the first place and people probably shy away from it because it’s not an off-the-shelf solution. But compared to the alternative of putting Windows 3.11 on 150 machines - we’d be running about all day.
“Getting the BootROM running from Novell was a bit tricky and getting the right version of the boot drivers was a trial but since then we haven’t had any problems with 150 machines for more than three years.”
Looking to the future, the advent of Windows NT/Citrix Winframe is an option being considered, as is Java - Linux supports Java natively.
Computer systems manager Gavin Picknell describes the BootROM process:
“Essentially the BootROM on the Ethernet card in your PC tricks the BIOS into thinking it is reading a startup disk from the floppy drive, when it’s actually reading a “startup disk image file” from a server.
The BootROM contains a small program that “bootstraps” the PC. Usually you get a choice on whether you want to boot from the network or not, but some BootROMs (Lanworks 3Com BootROMs, for example) are quite smart and can be programmed to take default actions.
If you choose to boot from the network, the program in the BootROM takes control of your PC temporarily. It will broadcast out on to the network asking if somebody knows what it should do to boot up. (If you are booting to a DOS/Windows workstation from a NetWare server, the BootROM generally uses the standard NetWare protocols for communicating with the server). The PC says My Ethernet Hardware address is XXXXX, tell me what to do. (The Ethernet address is unique and hard coded on the card.) The server will then check its boot file looking for a match on the address. If it finds one it will return some information that generally includes the name of the file the workstation should use to boot. The BootROM starts downloading the boot image as dictated by the server.
At this point the BootROM on the card tricks the BIOS. It passes the boot image it is downloading on to the PC as if it were being read from the floppy drive. The PC doesn’t know the difference - it thinks it is booting from a standard DOS boot disk in the floppy drive (you’ll even see the disk light come on).
At some stage the BootROM needs to pass control of the disk drive back to the PC and stop the download. If you’re booting a DOS/Win workstation from a NetWare server, this occurs when you load the NetWare client from the image file. At this stage, the BootROM stops downloading the image and releases control.
The PC is now in DOS, with all the drivers loaded and connected to the network and ready to go.
To make the floppy disk image under NetWare you configure a standard DOS boot disk that boots your workstation - it has the NetWare client cd/sound drivers etc. all the standard autoexec.bat/config.sys programs. Once you have this disk, you run a Novell supplied program called DOSGEN over the disk, this essentially copies the disk to one big image file in a format that is useful to the BootROMs, this is put in the LOGIN directory of the NetWare server (the only area that is visible before you log in).
Next you edit the server’s boot configuration file (under NetWare it’s in the LOGIN directory called BOOTCONF.SYS). This file is just a list of hardware addresses and the corresponding boot images that the machines should use.”