Dump questions

[Aiza]

Dan Nelson wrote:
> In the last episode (Feb 21), Aiza said:
>> 1. Using the -L flag to create a snapshot of the
>> live running file system.
>>
>> Does this mean that a complete copy of the file
>> system is written to .snap directory?
> 
> No; that would be a "copy".  Snapshots only copy blocks as they are modified
> on the parent filesystem, so their size is determined by how much data is
> modified since the snapshot was created.
> 
So how does this interact with the dump process?

Dump start reading and writing its dump file and as the live system 
changes the changes are written to the .snap and when dump completes it 
overwrites it dump with the changes from the .snap???

How does this process work in detail?