Newbie Q: Creating large test db

--
I'm asking this question on behalf of a colleague who is part of a group 
creating network backup products. In order to verify that their backup 
software correctly archives and retrieves fairly large Oracle databases 
to tape and back again they want to construct a fairly large, 1- or 
2-Gbyte database with modest variability among records. They are working 
on an HP-UX machine in C and are considering writing embedded SQL. Would 
you please suggest a better way, or offer comments about likely snags and 
pitfalls in this approach. Thanks very much in advance. - Bill Bell