DODonHopkins·May 10, 2025
Gosling Emacs used "unexec.c" by Spencer W Thomas (1982):
https://github.com/bobbae/gosling-emacs/blob/master/unexec.c
There was a FORTRAN version of ZORK (aka DUNGEON) by Bob Supnik at DEC, which was limited in some ways compared to the MDL version, but also had a "GDT" debug mode where you could inspect and control things like the thief and the troll and the cyclops and the robot.
I think you could tell them to perform commands, even become one of them, or have them pick you up and carry you around. I have a vague memory of being carried around by a robot in Zork, but I can't remember which version, or if that was part of the game or GDT. Something like "ROBOT, TAKE ME". Then it could carry you places you couldn't walk to yourself.
Bob Supnik started translating ZORK to FORTRAN in 1977, and published it on the DECUS tape library in 1978
Read the rest
.
You could type "GDT" at any time and it would go:
A booming voice calls out, "Who summons the right hand of the translator?
State your name, cat, and serial number!"
SUPNIK,BARNEY,70524
At your service!
GDT>
“Barney” was Supnik’s cat; 70524 his DEC badge number.
Zork Fortran Sources:
https://github.com/historicalsource/zork-fortran
GDT Sources:
https://github.com/historicalsource/zork-fortran/blob/master...
It had commands like:
900 FORMAT(' Valid commands are:'/' AA- Alter ADVS'/
&' AC- Alter CEVENT'/' AF- Alter FINDEX'/' AH- Alter HERE'/
&' AN- Alter switches'/' AO- Alter OBJCTS'/' AR- Alter ROOMS'/
&' AV- Alter VILLS'/' AX- Alter EXITS'/
&' AZ- Alter PUZZLE'/' DA- Display ADVS'/
&' DC- Display CEVENT'/' DF- Display FINDEX'/' DH- Display HACKS'/
&' DL- Display lengths'/' DM- Display RTEXT'/
&' DN- Display switches'/
&' DO- Display OBJCTS'/' DP- Display parser'/
&' DR- Display ROOMS'/' DS- Display state'/' DT- Display text'/
&' DV- Display VILLS'/' DX- Display EXITS'/' DZ- Display PUZZLE'/
&' D2- Display ROOM2'/' EX- Exit'/' HE- Type this message'/
&' NC- No cyclops'/' ND- No deaths'/' NR- No robber'/
&' NT- No troll'/' PD- Program detail'/
&' RC- Restore cyclops'/' RD- Restore deaths'/
&' RR- Restore robber'/' RT- Restore troll'/' TK- Take.')
Gunkies Zork info:
https://gunkies.org/wiki/Zork
GDT Command:
https://gunkies.org/wiki/Zork#The_GDT_command
>GDT dates from a very early version of the game, in fact, before the
game was actually finished. I realized early on that debugging an
interactive program with the traditional PRINT statements was going to
be very cumbersome, and that the interactive debug tools of the day
(1978) had no semantic understanding of the program. GDT was the
answer. It enabled me to track when things went wrong, and to simulate
parts of the game that hadn't been implemented yet.
>Originally, GDT was just a command like any other. Once the game was
released, players quickly realized that it offered a simple way to short
circuit the game and to undo mistakes. Lost something to the thief?
Take it back. Getting killed too often? Turn on immortality mode. So
I implemented a variety of challenges to prevent players from entering
GDT without making the mechanism too difficult for me to remember. I
think the INCANT mechanism might have been the final PDP-11 challenge.
>When I did the VAX version, I abandoned all that and went back to GDT as
universally enabled, under control of a run time flag, GDTFLG. I think
I intended to turn GDTFLG off before releasing the VAX version, so that
it would be impossible to get into GDT without patching the binaries;
but in fact the final VAX sources have GDTFLG=1.
>/Bob