The PC Weasel 2000

If you ask system administrators the benefits of Linux as a server, one ability that always seems to come up is remote access, or the ability to get into the server to do anything that needs doing, without needing to be where the machine is. Linux—UNIX in general—handles that wonderfully. Unfortunately, PCs don't. To access CMOS settings or watch a system boot, you need to have a display attached, and you need to be there watching. There is nothing Linux, or any operating system, can do about it.

But the PC Weasel can help. The PC Weasel is an ISA card that replaces the system video card in servers intended for headless (without monitor and keyboard) operation. It acts as a video card and, with the connection of a short cable between the card and the system's keyboard port, as a keyboard too. With the PC Weasel, the monitor and keyboard are replaced by an RS-232 connection and any standard terminal emulation (VT100 or ANSI) running on anything from a dumb terminal to a handheld computer to another server.

That isn't all the Weasel can do. On motherboards with reset connectors, the PC Weasel can provide remote reset control that allows you to reboot locked servers or disable computers that may be causing problems on your network. There is also a watchdog timer mode, allowing the PC Weasel to reset the system automatically if the OS locks up, or it at least stops telling the card that everything is okay. Watchdog support requires kernels with PC-Weasel watchdog support, and you may need to patch your kernel to get this.

Having a serial console on a PC provides many advantages, not the least of which is that you can control a lot of computers from one workstation by using multiport serial cards or inexpensive RS-232 switch boxes to connect all of the headless servers to the workstation. This can save effort and time if you have a lot of rackmounted PCs. But, far more valuable, the PC Weasel allows you to place servers in remote locations and provide true remote administration. You can connect a standard external modem to the PC Weasel and have dial-in access to the computer—not just the running operating system, but the whole machine. You can watch the system self-test, change BIOS settings, view POST codes, diagnose failed hardware and do a few other jobs that usually mean having someone present with the computer.

And the PC Weasel isn't limited to Linux. It will work with any OS that supports text-mode video, including DOS and most UNIX variants.

The PC Weasel manual is a spiral bound mini-tome of engineering wit and detail—a lot of detail, including everything from how to set the board jumpers to compiling custom code to run on the PC Weasel's on-board microprocessors. Though it tends to jump into low-level details with both feet, there is enough general information that anyone with a fair tolerance for jargon can get what they need. Given that the PC Weasel is aimed at a traditionally tech-savvy user base (system administrators, technical support personnel, embedded systems developers, etc.), the documentation is probably exactly right: human enough to be fun to read, but technical enough to be precise.

These days, when it seems like everyone has ADD, a lot of people (me, for example) would benefit from a single-page reference guide with nothing but the few facts most people would need who use the PC Weasel card. The card is fairly self-explanatory, but such a guide would be nice.

First the limitations: you need an available ISA slot; the PC Weasel doesn't come in a PCI version. Second, you can't have another video card installed in the computer alongside the PC Weasel. Given that, installing the PC Weasel is fairly simple, provided your computer's motherboard is willing. An unfortunate number of modern motherboards have video controllers built in, and unless the on-board video disables itself properly when the PC-Weasel card is installed, you may have problems. The PC Weasel's keyboard connection is made by way of an external jumper cable that is just a little bit messy and prone to being yanked out by careless people working around the computer. The reset feature requires that your motherboard have a reset jumper, a feature that a few new motherboards seem to be skipping.

The most painful part of installing a PC Weasel may very well be finding an ISA slot and the reset jumper on your motherboard. After removing the old video card, inserting the PC Weasel and hooking up the various cables and connecting your RS-232 cable to a PC or terminal, everything pretty much works.

The PC Weasel defaults to a safe 9600 baud communications rate, adjustable once a terminal is connected. The configuration is stored in nonvolatile EEPROM, so you don't have to worry much about forgetting your settings.