We are in the middle of the January 2018 snapshot. Time to understand the inner workings.
First: The upcoming IRI update includes a long list of addresses and balances.
However, strictly speaking there is no such entity as an address on the tangle. There are only transactions. The sum of all non-zero transactions pointing towards address A constitute its balance.
Now, a snapshot removes all zero-transactions from the tangle but doesn’t touch those with value. Is this correct?
If it is: Why do we need Snapshot.txt at all?
Second: How does IRI make use of Snapshot.txt? Does it use it to seed an (empty / new) database? Is reading it into memory and performing lookups?