We start this week with a follow-up to the amuse-bouche portion of last week’s dining experience. But first, let’s refresh your memory: The topic concerned a problem raised by reader Don Janeway. He wanted to boot from a floppy so that it, in turn, booted a Live CD (a bootable Linux distro on a CD) in the CD drive. (This was because the BIOS of Janeway’s machines is old enough to not support CD booting.)
Reader Chris Lucht suggested using the Smart Boot Manager (SBM), which can be found on the first CD of the Debian 3.0r3 distribution.
From the original SBM Web site , SBM is: “Smart Boot Manager . . . is an [operating system] independent Boot Manager – a program that is loaded by the [BIOS] before any operating system and allows you to choose which operating system to boot. It’s like OS/2 Boot Manager and many other similar programs, for example System Commander, Bootit, Bootstar, PQBoot. But it’s not an OS Loader; it’s not a replacement for LILO or other OS Loaders. In other words, you must use LILO (or other similar programs) to boot Linux . . . using SmartBtmgr to give you an easy to use interface to boot [from] multiple [operating systems].”
The last release was Version 3.7, which you won’t find on the original SBM site but rather on the SourceForge SBM sub-site .
Anyway, Janeway last week made floppies of SBM under DOS, Windows 95,98 and ME. The creation of the floppies seemed to be successful but when he tried to boot an SBM floppy on any machine other than the computer the disk had been created on, the boot failed and displayed the message, “SBMK Bad!” It seems that each machine that he tried had a different type of floppy disk controller.
We got an update from him last week: He used rawrite3.com (DOS) and rawwrite win-0.7.zip (Windows 9x) to make the SBM boot disk and now he can “make SBM work on several computers with several [operating sytems] (IBM ThinkPad WinXP, PC’s x386 and x586 running Win 3.1, 95 and 98) [but] the old Dell laptop (Win ME) refuses – I still get SBMK Bad regardless of FD controller. Must be something in the Dell BIOS, or the floppy drive itself. I don’t have another Dell floppy drive to try, so I’m stuck there.”
We found a comment in a Web forum that SBM is finicky. The author, Jeffrey Cunningham, suggested that when you create the SBM floppy, you should immediately write-protect the disk. When SBM prompts you to “save changes,” you should respond with ‘n.’ If you allow SBM to write to an unprotected floppy, the next time you boot you will get the “SBMK Bad!” error message.
Interestingly, Cunningham concluded that if SBM still gives a disk error, the cause is your CD-ROM drive or whatever source you’re trying to boot from. He also found that older Dell CD-ROM drives are not bootable using SBM or any other method, and suggested replacing the CD-ROM drive. This is an arcane problem. Any thoughts on why some FD controllers would cause problems?
A few months ago we discussed a simple software proxy server . Many readers responded wanting basic information about deploying proxies and what to do in an enterprise environment. A good topic. Let us start with the basics:
A proxy server usually serves multiple roles: It always acts as a security device, and its optional functions are as a network management tool and/or a performance enhancement subsystem. At its simplest, a proxy server accepts requests from one or more computers and relays those requests to other computers to screen and/or control the access of PCs on an internal network to services on the Internet.
By blocking or limiting inbound connections (technically termed “IP forwarding”) made from a WAN to a LAN and presenting the Internet with a single outbound IP address, a proxy server provides features similar to those of a firewall protecting the LAN from external intrusion.
Things get interesting when a proxy server is used as performance enhancement subsystem. Because a proxy server examines every protocol exchange and relays requests, it can keep copies of the data so that multiple requests for identical content can be satisfied from a cache rather than having to re-issue the request to the remote server. Not only does this reduce WAN connection loading, but retrieving content from the proxy cache instead of a remote server can be orders of magnitude faster.
Next week, we’ll delve into proxy technology. Until then, send your requests directly to gearhead@gibbs.com.
