Zork Zero, MS-DOS retail release (1989) - findings

The catalog’s first floppy entry: an original dual-media retail box - two 720K 3.5” diskettes and three 360K 5.25” diskettes - fully imaged and hashed (checksums.txt): the 3.5” side 2026-09-12 via a USB floppy drive, the 5.25” side 2026-09-13 via a Greaseweazle V4.1.

Contents of the 3.5” diskettes

See zork-zero-1989-dos.ls.txt for the full listings.

• Disk 1 (ZORK0 1): ZORK0.ZIP (r393.890714), ZORKZERO.EXE (interpreter, 47,494 bytes), ZORK0.MG1 (the MCGA graphics, 226,436 bytes, 1989-07-10 11:35 - matching Doherty’s documented timestamp to the minute), INSTALL.EXE, IZORK03.RUN, EZR.EXE.
• Disk 2 (ZORK0 2): ZORK0.CG1 alone, 244,507 bytes, with some 476K of the diskette unused.

There is no ZORK0.EG1 on the 3.5” set.

Findings

• The MG1 provenance question is closed. This box’s ZORK0.MG1 is byte-identical to the IF Archive’s zorkzero.mg1, uploaded 1994-05-16 to patch the Lost Treasures omission. The archive’s copy is the retail 3.5” edition’s file; see docs/media-assets.md for the full chain.
• The compilations’ Zork Zero traces to these diskettes. ZORK0.ZIP, ZORKZERO.EXE and ZORK0.CG1 are byte-identical to the copies on the 1992 Lost Treasures CD and everything downstream of it. The CD lineage (1992 -> 1994 -> 1996 -> 1997) now begins at physical retail floppies.
• The graphics renditions were media-targeted. The 3.5” set carries MCGA plus the CGA fallback but no EGA file - and not for lack of room, since EG1 (333,654 bytes) would fit disk 2’s free space. On the 5.25” side the arithmetic runs the other way: three 360K diskettes (1,087,488 bytes) can hold the game with EGA and CGA, but adding the MG1 would force a fourth diskette. So each media format shipped the renditions matching its buyer’s likely hardware - 3.5” for PS/2-class MCGA machines, 5.25” for the older EGA installed base, CGA as the universal fallback - the same policy Graeme Cree describes for Journey’s dual-media box, where the VGA rendition rode only the 3.5” diskettes.

Contents of the 5.25” diskettes

Imaged 2026-09-13 with a Greaseweazle V4.1; 360K double-sided (the first captures, decoded single-sided by mistake, betrayed themselves with a 0xFD double-sided FAT byte in a 180K-sized image - flux capture made the redo free for disk 1).

• Disk 1 (ZORK0 1): ZORK0.CG1, INSTALL.EXE, IZORK0.RUN, EZR.EXE.
• Disk 2 (ZORK0 2): ZORK0.ZIP, ZORKZERO.EXE.
• Disk 3 (ZORK0 3): ZORK0.EG1, alone - 333,654 bytes filling a 360K diskette by itself, the fits-with-2K-to-spare sizing that explains why the EGA rendition drove disk counts.

Findings from the 5.25” side

• The media-targeting prediction held exactly: EGA and CGA renditions present, no ZORK0.MG1 - the mirror image of the 3.5” set, as predicted when the 3.5” side was imaged.
• All four game files are byte-identical to the LTOI1 copies (ZORK0.ZIP, ZORKZERO.EXE, ZORK0.CG1, ZORK0.EG1), and every timestamp matches Doherty’s graphics-file table to the second. Both sides of the box now anchor the compilation lineage.
• The install scripts differ by media: IZORK0.RUN here, IZORK03.RUN on the 3.5” set.

Open items for this disc

None.

Resolved 2026-09-13: the 5.25” diskettes imaged; the media-targeting prediction confirmed; see above.