COR CAROLI (Alpha Canum Venaticorum). Third magnitude (2.81, nearly second) and easy to find, the star’s importance is consistent with its brightness.
86 DOS Version 0.1 C Serial # 11 (ORIGINAL DISK) (archive.org) This is the precursor to MS-DOS and is likely the oldest known version to survive. (I had previously uploaded Version 0.34, which was at the time thought to hold that honor.)