The dates on the disk are a bit weird. It appears to be something like Cairo or Neptune, stock MS-DOS 4.01 dated 07-04-1989 (DD-MM-YYYY) but the 2 Bondwell-specific files (BWUT.COM and TOPCAT.SYS) appear to be later copied onto the disk at 06-09-1990 for BWUT.COM and 11-03-1991 for TOPCAT.SYS.