a currency that has a value which is loosely tied to an average cost per GB of a consumer level storage device
How would a peer to peer system know average cost per GB of a consumer level storage device ?
Good point. I guess the clients could use a fitting formula based on historical data, with an update to the client required if there's any major change in projections versus real world values. The idea of buying a few TB worth of HDs rather than a GPU or ASIC appeals to me.
so no mining is needed at all, just some proof that the allocated data space is dedicated to that block
For this to happen,the proof of existence of data had to be periodically checked, in a secure decentralized way. Otherwise the node can verify the block of data for once, and later delete it, and falsely claim existence of the data which it does not have.
Yes, ongoing proof would be required, perhaps in the form of a unique challenge from a peer which also holds that block - what is the hash of the stored data plus <random_key>. I guess in this case the block chain would need to contain a permanent record of the result of those challenges, so that future rewards for the peer will decline as it fails more checks for valid data. A long term trust system (such as a gradual increase in reward) for new peers would also be necessary to discourage a peer from just periodically deleting data and starting over from scratch as a new peer. It would need to be balanced to ensure that in the medium to long term it's more cost effective to keep the data, rather than try to cheat the system.
