2072 Cardfile Database Cardfile (also Card File or CardFile) is a personal information manager, based on index cards. It was initially released with Windows 1.0. 234 National Library of Australia / National Library of Australia 18 Jan 2020 18 Jan 2020 fmt/1254 PUID crd File extension 1628 Cardfile (MGC) BOF: Magic bytes ‘MGC’, ‘RRG’ or 'DKO' at beginning of file. The initial versions of Cardfile have the magic bytes 'MCG'. When Cardfile updated to add OLE support the file signature changed to 'RRG'. Finally the file signature changed to 'DKO' when released as a 32-bit accessory and the character width changed in order to support unicode. 1 Absolute from BOF 0 2 4D4743 1647 Cardfile (RRG) Cardfile updated to add OLE support and the magic bytes changed to 'RRG' at the beginning of the file. 1 Absolute from BOF 0 2 525247 1648 Cardfile (DKO) The magic bytes changed to 'DKO' at the beginning of the file when released as a 32-bit accessory. 1 Absolute from BOF 0 2 444B4F