backup and restore at the same time

SQL Server 2008 R2

i don't see a "general discussion" thread and this is the closest i think.

i just have a general question: if my backup window is from 8am to 10am, and i do a restore within that backup window, what will happen? assuming we're talking only of a single database, ACME.

i'm comparing because with Oracle RMAN, it pukes when i do a restore while the backup is going on. it would complain of unable to find some archive logs.