So far things are progressing according to plan. The instructions that professor Cox has provided are nicely accurate, and to the point. There is not a lot of wasted motion here. There are a few observations about the construction process that I have:
- The Pi doesn't boot sometimes if you put the SD card in before giving it power. Pulling the card and re-inserting with the power already on seems to make things work.
- Mounting the Pis on a board is a practical thing to do early in the process. Right now, the one Pi that I'm working from just hangs in mid-air between the CAT5 and HDMI cables - a sub-optimal configuration.
- The stuff that you find in regular retail stores varies a lot in price and capability. Since the total cost will be a multiple of the per-node cost in this configuration, things can add up quickly. My full configuration will be 8 nodes, and although I ordered all 8 Pis at once, I've decided to buy the rest of the parts as-needed, until I'm sure that I'm getting the right stuff.
- For each node you're going to need an SD card and a power cord. So far I've chosen 16 GB cards, and this seems like a good size to give a reasonable amount of local storage at each node. I've bought 2 cards so far - one for $14.99, and one for $19.99. The cheaper one claims to be fast, and the more expensive one claims to be faster. I do notice that the apparently faster one seems to allow the Pi to boot and run faster, but that's just a subjective impression. Most common 16 GB SD cards out there seem to cost between $29.00 and $39.00, which seems pretty high. I'm going to buy the other 6 cards that I need online, and get something that is a good balance between speed and cost. The power cords are a similar mixed bag. I've paid $19.99 for each of the 2 USB/micro USB cords, and $9.99 for a 2 port charger to plug them into. The charger price seems ok, but I really think I can do better than $20 for a 3 ft. long USB cord from an online source.
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