Electric: why would you need the jtag connector? The board has jtag for debug purposes only, everything should be handled via USB during real world usage.
Not too sure if you can mount 2 boards in a bay without needing a high CFM fan to push air to cool the FPGAs. Maybe it'd be possible if we can find some custom or weird heatsink that has 2 flat sides and then mount the top board upside down onto the same heatsink, and then put 2 fans to blow air across, if you get what I'm thinking.
Well, you're right it's probably not really necessary but might be a nice to have for people who would like to actively develop the miner.
I probably will make 2 a version with and without a frontpanel, so that the version without the header is basically a frame (probably all people who use it for strict mining need)
On the heat issue: I am working on a hexagonal grid top/bottom wall for the enclosure so that optimal convection and rigidness is provided, lets say the concept already looks awesome
I will also provide mounting options for fans where ever possible so that heat will be no issue but from what I figured so far it probably won't be necessary.
The full cases will also work as a standalone unit outside the PC and they will be stackable! It will have hexagonal feet with will fit into the hex pattern on top of the enclosure.
I like your profile pic, Mucus, and I really like these ideas you're coming up with! For my own FPGA boards, I'm liking that internal 5.25" drive bay idea! Making the enclosure work outside the computer is a great idea, too, when people end up with more boards than will fit inside their case.
As li_gangyi said, the JTAG connectors
should never need to be used. The USB interface can be used for development (it is JTAG over USB). If someone really wants direct access to the JTAG headers, they'll probably just keep the board sitting on the desk.
The heat issue is going to be very important, especially as people push the FPGAs to higher and higher clock rates. Some fan inside the enclosure is definitely required, with the air blowing across the heatsinks. If we get horizontal air flow, venting above and below the board can actually be a bad thing. It's better for the enclosure to basically become a little wind tunnel. Another option is to mount a larger fan (80 mm) directly above the board (to the inside of the lid) and blow air down on the heatsinks. The venting would then be out the sides.
Great work! I'm excited to see the first sketches.