Comment by ndiddy

The "OS" on the drive stands for "off-spec". As far as I understand, here's where they come from:

1. A large company (think cloud storage provider or something) wanting to build out storage infrastructure buys a large amount of drives from Seagate.

2. When the company receives the drives from Seagate, they randomly sample from the lot to make sure the drives are fully functional and meet specifications.

3. The company identifies issues from the sampled drives. These can range from dents/dings in the casing or torn labels to firmware or reliability issues.

4. The company returns the entire lot to Seagate as defective. Seagate now doesn't want anything to do with these drives, so they relabel them as "OS" with no Seagate branding and sell them as-is at a discount to drive resellers.

5. The drive resellers may or may not do further testing on the drives (you can probably tell by how much of a warranty a given reseller offers) before selling them onto people wanting cheap storage.