STORY
Hacking the PDP-11 Advent Data File
Hacking the PDP-11 Advent Data File
- Reverse engineering the FORTRAN
adventdata files on a PDP-11 at Tektronix to inject unique room serial numbers into description texts, making maze mapping effortless. Room-Numbered Advent Data File Hack
- Around 1979–1980, while working for Tektronix on a PDP-11 (running RSTS/E and later 2.8BSD Unix), I played the classic game advent (Colossal Cave Adventure), which had been distributed through DECUS.
- Rather than attempting to patch the binary itself, I reverse engineered the binary's associated FORTRAN data files.
- In a pre-Perl and pre-Awk era, I wrote custom C code to modify the data file, injecting unique serial numbers directly into the description text of each room (e.g., "You are in a maze of twisty tiny passages, all alike... ROOM 214").
- This made mapping the complex maze trivial within a few hours, completely bypassing the laborious standard technique of dropping various inventory items to identify room locations.
These facts are as Randal recalls them, but much time has passed for most of this. If you find a factual error, please email realmerlyn@gmail.com.