The Hillbilly Supercomputer!

Side view.	Two hubs used to connect the stack to my home LAN.	This power supply runs the bottom six boards.
This power supply runs the top five boards.	Every other board is mounted inverted. This allowed me to mount them closer together.	The boards are resting on four blocks and are not bolted down. This makes it easy to remove a board.
Floppies used to boot Linux and the command line client.	The stack with a UPS now installed and an old notebook running S@H.	Some old PC's that I use as disk storage. They are also running S@H.

I have boxes full of surplus Pentium motherboards at work. I decided to use a few to boost my SETI performance. This stack has 11 boards running at various speeds from 166MHz to 233MHz. All are running Linux booted from a floppy. They are minimum systems with no hard drives or video cards installed. All they have is a network card. I used some old AT power supplies that can pump out about 25 amps @ 5VDC. Since these are minimum systems running a much more modern motherboard, I was able to power them all up with just two power supplies. Those old AT class PC's used a lot more current! This stack is running at home in my basement. I Telnet into them every week or so and check their progress. Since they run from a RAM disk I lost all work units in progress when the power failed. I now have the stack running on a UPS. Short power failures are no longer a problem.

Ten PC's on left side of rack.

Ten PC's on right side of rack.

Another view showing all twenty.

Here are twenty obsolete PC's that are running SETI@thome from the Linux LRP boot floppy. The hard drives were removed for use in other PC's. The two racks in the center are the main distribution frame for the school. The white box behind the racks is an obsolete 10Mb 24 port ethernet switch. This is connecting the twenty PC's to the LAN. Most of them have A P133 CPU. A few have a 166MHz CPU. They all have 32MB of RAM. Stacking ten of these is starting to reach the mechanical limits of the computer case. Look closely at the second one from the bottom in the right hand stack. The case is starting to buckle!