AppleCrate I

November 24, 2004
Revised: October 04, 2008


What is an AppleCrate?

Here are a couple of pictures of the 8-processor AppleCrate I. In them you can see the simple wooden frame used to hold eight Apple //e boards. The system is powered up, as you can see from the power LEDs and the "speaker" LEDs. (You can also tell that I'm not a carpenter!)

Since this was initially written, I've constructed a 17-processor AppleCrate II using a different construction methodology and Enhanced Apple //e main boards, and incorporating an integral "master" processor so that it can be used as a self-contained unit. I've also revised the network boot protocol so that the boot code will fit in the ROM of an Unenhanced or Enhanced Apple //e.

If you look closely, you will note that I added blinking green "send" LEDs attached beside the cassette jacks. This is a snapshot of its appearance while it is waiting to be booted over the network by a "master" machine.

In the second shot, you can see the little interface perfboard on the bottom, right side that connects via NadaNet to other machines.

I originally hoped to use the board edge connectors that Apple used at burn-in to power the boards, but discovered that different board revisions have different edge connections, and none have all the voltages normally supplied. So I decided to use threaded rods as power (on the bottom) and signal (on the top) busses.

I've written some articles describing AppleCrate and its use:

AppleCrate: An Apple II-Based Parallel Computer
BPRUN: Broadcast Parallel RUN for NadaNet
AppleCrate Parallel Work Simulator
AppleCrate Polyphonic Music Synthesizer

Here are links to current Merlin Pro listings of the software:

NadaNet (AppleCrate version)
ROM boot