I just posted one topic about Pawn Dac yesterday , and  should  finish that  at first. 
But I think this one may be more important and can not wait to get some feedback from experts  

.
This is about set up one  Database DAC for the whole DACs Network.
Why this one is necessary?
We can see more and more Dacs are coming out ,and more and more data will be poured into the blockchains. 
But lots of DACs  will  suffer from limited data space of each block (like the problem XCP met at present) .
So ,maybe we need one unique Database Dac to contain big data  from all kinds of DACs, and each Dac just builds up its business blockchain and throws big data into the Database Dac. 
How does this Dac work?
1、 Set up one decentralized and distributed database system , like breaking up one huge oracle database and make it decentralized and distributed .   (maybe this is very  dificult to realize , but I believe it is worth doing  )
2、 Build up one wallet which can mining database dac by contributing harddisk space and network bandwidth.
3、 If one third party dac want to use this database  ,pay for its space and time occupancy. 
4、 The revenue is dividends 
  Maybe my idea is immature or even innocent , I just want to know how about this ?  and could  3i team perform this DAC?
  thanks.