Sometimes it's tricky to find out from the label, so I look on the underside of the HDD to check for any datecodes on the ICs. If you're luck this should roughly give you the manufacturing year of the drive...

Well, I was kinda hoping, it will resolve this mystery, and someone will know, how exactly differenciate Seagate drives, if it is fiscal datecode, or classic YYWW datecode. 🙁

I've found good article, that brings more light into this mystery.

https://www.os2museum.com/wp/decoding-seagate-date-codes/

The bad news is, that even the author doesn't know when Seagate turned into fiscal datecode on consumer hard drives. He only approximates it - somewhere in FY98 (Fiscal year 1998, that means 99ww datecode ). Problem is, I've never seen 5-digit datecode on 99' Seagate Medalist drive. Only 4 digit ones. That implicates, that they are in YYWW format, because for fiscal year format, you need also 5digit code to cover whole year, and 5-digit code should be much more often seen than 4-digit one (as they need to cover 10-55 weeks, instead only 0-9, which is 5 times longer time period)

I've also found something that contradicts that

this is the drive with 05097 datecode. That mean, 9th week is in "09" (not 9) expression, making it 5-digit code, while according definition, it should be 4 digit code. (as for 1-9 weeks, W, not WW should be used). Maybe, it can be both? That would be even more confusing.

https://www.donordrives.com/st330015a-5jx-wu- … hard-drive.html

Based on 9941 and the January 1999 manual for the drive: https://www.seagate.com/support/disc/manuals/ … si/17240pma.pdf
I say it was made in week 41 of 1999....