“Why Do My Backed Up Files Appear Smaller On Backblaze Than On My Mac?”
Decimal and binary units explain the apparent size difference
Backblaze on how OS X displays file sizes:
Starting with Mac OS X 10.6, Apple calculates disk storage using decimal (base 10) math:
- 1 KB is 1,000 bytes
- 1 MB is 1,000,000 bytes or 1,000 KB
- 1 GB is 1,000,000,000 bytes or 1,000 MB
Backblaze’s restore browser, Windows, and Mac OS X 10.5 and earlier all use binary (base 2) math:
- 1 KB is 1,024 bytes
- 1 MB is 1,048,576 bytes or 1,024 KB
- 1 GB is 1,073,741,824 bytes or 1,024 MB
Why on Earth would they use base 10?