This worries me. Bitcoin solved the double spend problem by using the LCR with PoW. That is the novel aspect which allowed cryptocurrencies to come into existence.<p>If you remove the LCR and PoW, all you are left with is a toy example which cannot work in practice.<p>What is needed is education about censensus design and bitcoin's implementation of the solution, rather than a 'how to guide' for building a basic linked list under the guise of 'blockchain'.<p>Cheers, Paul.
Regardless of the semantic discussion on what exactly a 'blockchain' is and whether or not this qualifies, I found the article interesting by taking a tiny piece of the whole monster and demystifying it a bit.<p>I don't see this any differently than a tutorial that makes a static image move around the screen with key presses. Is it a full game? Not at all. But can it teach you how to build a tiny piece of it, and you can look at other tutorials to figure out how to build other tiny pieces of it, and eventually synthesize that knowledge and make a full game? Yes.
So ah... where's the part where you implement a working blockchain, again? There's no proof-of-work, consensus logic, currency logic, accounting logic, peer-to-peer networking code, etc.<p>Instead this is just a list of hashed-linked documents... Not that much different from a Git repo or a basic file system with integrity checks. Hashing != blockchains.
Clearly there's an association to Bitcoin and there are certain expectations by people when mentioning blockchain.<p>It's justified since blockchain on its own is a relatively simple data structure which on itself is not that significant. It's the composition of all the elements that have given the value and recognition to this technology.
I wanted to try re-writing in Ruby to warm up today. Can someone confirm this is correct? <a href="https://gist.github.com/chrisallick/cb196b13555c86f9193f3ec4f7f15ecc" rel="nofollow">https://gist.github.com/chrisallick/cb196b13555c86f9193f3ec4...</a>
Regardless of the quality of the article, it's refreshing to see so many good questions and concise answers in this thread (mostly about blockchains-as-distributed-ledgers). It's been a while since I saw such nice, civil and interesting technical discussion on hn.
I've got a JS block-tree here. The root block is hashed from user content. <a href="https://github.com/jchris/document-coin" rel="nofollow">https://github.com/jchris/document-coin</a>