[philh]

How confident are you?

I know very little about Minecraft, but if this doesn't work, it pretty much has to be trolling. (No way you build something like this and not notice that it doesn't work.) And then I wouldn't expect them to offer a link to download the map, and I wouldn't expect someone else to say they've got it working: http://www.reddit.com/r/Minecraft/comments/2e0ghk/fully_func...

[thejj]

ok, it does work. i totally forgot about the command blocks. he's using them to change the block type.

[thejj]

Imagine a write process: You'd need to somehow replace the visible blue blocks with a green block. But where does the green block come from?

[josu]

I don't know much about MC or computers, but as far as I understand each bit has both blocks, shift up for blue=0, shift down for green=1. Here: http://i.imgur.com/rqZm4DU.gif

[thejj]

Yes, but you don't see BOTH block types on the big tape. Swapping bits requires one block for each state, but the green ones are missing from the tape screenshots.

[josu]

I don't think that they have to necessarily be green. So the fact that you don't see them may not mean that they are not there. He may be using blocks the same color as the structure for aesthetic purposes.