Q: I have a 60GB Photo iPod that seems to have lost about 4Gb of disk space. The total size of the files contained in the iTunes Library is 39.95Gb; The iPod reading is showing 40.02Gb used and 15.73GB free. That totals 55.75GB. What has happened to the remaining 4.25GB? I have nothing set up for photos or other files and have tried resetting to factory condition, but with no luck. Any ideas?
A: We occasionally revisit this issue, but the answer is always the same: it’s not missing… you’ve been a victim of marketing spin. Hard drive and device manufacturers advertise a gigabyte in “decimal” terms, where 1GB = 1,000,000,000 bytes. However, computers and devices interpret this storage space in “binary” terms, where 1GB = 2^30, or 1,073,741,824 bytes.
The ratio of these two interpretations is roughly 0.931, which explains why you’re seeing approximately 93% of your total storage. We have a more detailed FAQ on the issue here.