Interbase Shadowing

[ds...@gwu.edu]

Hello,

I am doing presentation of Borland Interbase for my school project.
However, I have yet to understand Shadowing-recovery.

Most of the document state advantages, disadvantages, and very general
nontechnical concept.

Question I have is:

Document state that shadwoing can recover a record that was accidently
deleted by user error. However, if records changed take place on a two
copies of a same database, wouldn't deletion also be reflected on both
copies of database?

Another way to put it is, if you change something on the "master disk"
wouldn't same change take place on a "shadow file"?

Can someone explain to me what I am missing here?

Thanks