Difficulty level in private network

Question

This article has a good description on how Ethereum calculates a difficulty level. And, this article mentions that the difficulty is adjusted such that, one block is generated every 12 seconds.

The difficulty dynamically adjusts so that on average one block is produced by the entire network every 12 seconds (ie., 12 s block time).

1. What is the co-relation between this difficulty adjustment and the value of difficulty in a genesis.json document?
2. In a private Ethereum network, once set in the genesis.json, does the difficulty level adjust automatically similar to the main network?

genesis.json parameters explained

Answer 1

1. The genesis.json file determines the starting difficulty- this is used to prevent the first miners from achieving a great portion of the coin. The co-relation is that this value is adjusted overtime according the net's algorithm
2. Yes, This algorithm is implemented as part of the Ethereum network, private networks function the same as the main network is this aspect