Seagate Date Code From Serial Number
The good news is that Seagate no longer uses the cryptic date codes and prints a full date of manufacture on their drive labels, just like everyone else. The bad news is that there are countless millions of Seagate drives made before 2016 or so out there, and most of those drives only have the hard to decipher date code.
seagate date code from serial number
The four- or five-digit date code consists of a two-digit year, one- or two-digit week number (starting with 1), and one-digit day of the week (again starting with 1). If the week number is less than 10, the leading zero may be left out; that seems to have been the case on older drives, but later Seagate apparently switched to consistent five-digit codes.
Note that some IBM/Lenovo OEM drives have two labels, the standard Seagate one and an additional IBM/Lenovo sticker. The Seagate date code as well as the human readable date are usually both on the Seagate label, i.e. printed by Seagate, and presumably printed by someone who knows exactly how to decode the date codes. These drives can be used as a sort of Rosetta Stone.
Using the above rule, I threw together a simple Python script to convert a Seagate date code to a calendar date. The results perfectly match more than a dozen different Seagate-made IBM and Lenovo OEM drives produced between 2002 and 2016.
It is known that the older lot number format appears on drives made at least as far back as 1989, some still under the Imprimis brand. It is currently unknown whether those lot number dates referred to the same start of financial year.
Seagate style date codes have been seen on drives manufactured as late as 2016. Some drives made in 2016 and most if not all drives manufactured since 2017 no longer use the date code and instead show a human readable date in DDMMMYYYY format (where MMM is a three-letter English month abbreviation).