Ness and Vlad are right....1 billion bytes is a GigaByte, and 1024 GB is a TerraByte.
For future reference:
1 B = 8 bits
1 KB = 1024 B
1 MB = 1024 KB = 1,048,576 B
1 GB = 1024 MB = 1,048,576 KB = 1,073,741,824 B
1 TB = 1024 GB = 1,048,576 MB = 1,073,741,824 KB = 1,099,511,627,776 B
- tf