open-adventure/history.adoc

= A brief history of Colossal Cave Adventure =
by Eric S. Raymond

Adventure is the fons et origo of all later dungeon-crawling games,
the grandaddy of interactive fiction, and one of the hallowed artifacts
of hacker folklore.

The very first version was released by Crowther in 1976, in FORTRAN on
the PDP-10 at Bolt, Beranek, and Newman. (Crowther was at the time
writing what we could now call firmware for the earliest ARPANET
routers.) It was a maze game based on the Colossal Cave complex in
Kentucky, including fewer of the D&D-like elements now associated with
the game.

Adventure as we now know it, the ancestor of all later versions, was
was released on a PDP-10 at the Stanford AI Lab by Don Woods in 1977
(some sources, apparently erroneously, say 1976). That version is
sometimes known as 350-point Adventure.

Between 1977 and 1995 Crowther and Woods themselves continued to work
intermittently on the game. This main line of development culminated
in the 1995 release of Adventure 2.5, also known as 430-point Adventure

The earliest port to C was by Jim Gillogly under an early Unix running
at the Rand Corporation in 1977; this version was later, and still is,
included in the BSD Games collection.  It was blessed by Crowther and
Woods and briefly marketed in 1981 under the name "The Original
Adventure".

Many other people ported and extended the game in various directions.
A notable version was the first game shipped for the IBM Personal
Computer in 1981; this, for which neither Crowther nor Woods nor
Gillogly were paid royalties, what "The Original" was competing
against.

The history of these non-mainline versions is complex and
murky. Functional differences were generally marked by changes in the
maximum score as people added puzzles and rooms; however, multiple
ports of some versions existed - some in FORTRAN, some in C,
some in other languages - so the maximum point score is not
completely disambiguating.

Same articles at <<DA>> are a narrative of the history of the
game.  There is an in-depth study of its origins at <<SN>>.
Many versions are collected at The Interactive Fiction Archive
<<IFA>>; note however that its dates for the earliest releases
don't match other comments in the code or the careful reconstruction
in <<SN>>.

Future versions of this document may attempt to untangle some of the
non-mainline history. For now, it will suffice to explain the chain of
provenance that led from the original Adventure to the version
distributed with this document.

The original 350-point ADVENT on the PDP-10 had been one of my
formative experiences as a fledgling hacker in 1976-77. Forty years
later, in February 2017, while doing some casual research into the
history of text adventure games, I looked through some source code at
<<IFA>> and was delighted to learn of Adventure 2.5, a version of the
Crowther-Woods mainline later than I had ever played.

Adventure 2.5 had been shipped long enough ago that today's conventions of
open-source licensing were not yet fully established. The Makefile
contained a rights reservation by Don Woods and that was it.

I wrote to Don asking permission to release 2.5 under 2-clause BSD;
he replied on 15 May giving both permission and encouragement.

Here is what Don said about differences between the original Adventure
and 2.5:

............................................................................
> The bulk of the points come from five new 16-point treasures.  (I say "bulk"
> because I think at least one of the scores included some padding and I may
> have tweaked those.)  Each of the new treasures requires solving a puzzle
> that's definitely at the tricky end of the scale for Adventure.  Much of the
> new stuff involves trying new directions and/or finding new uses for stuff
> that already existed; e.g. the forest outside is no longer a small number of
> locations with partially random movement, but is a full-fledged maze, one
> that I hope has a character different from either of the previous two.
> 
> As the text itself says, V2.5 is essentially the same as V2, with a few more
> hints.  (I think I came up with a better one for the endgame, too.)  I don't
> seem to have a copy of the similar text from V2, so I don't know whether/how
> it described itself to new and seasoned players.
> 
> The other big change, as I mentioned above, was I added a way of docking
> points at a certain number of turns.  This was my second attempt to do what
> the batteries had been for: require being efficient to achieve top score.
> Alas, the batteries led to players deliberately turning the lamp off/on
> whenever they weren't moving or were in a lit area, making the game take
> even longer!  I set the requirement at what felt like a hard but fair
> number of turns, then applied several sneaky tricks to shave off another
> twenty.
>
> I hacked up a wrapper around the game (still in Fortran, most likely, but
> I forget) that would try each initializing the RNG using each second of a
> given day, while feeding in a script that either worked or aborted early
> if anything went wrong (such as a dwarf blocking my path).  As I recall,
> it took less than a day's worth of RNG seeds to find one that worked.
>
> I verified my script could work given a favorable RNG, and stuck
> that number in the message.
> 
> I like how that final puzzle, unlike the game itself, does not readily
> succumb even given access to the game source.  You really need to fit
> together not only the goals and the map and use of inventory space, but
> also details like just what _can_ you do in the dark...?
............................................................................

== Nomenclature ==

This project is called "Open Adventure" because it's not at all clear
to number Adventure past 2.5 without misleading or causing
collisions. Various of the non-mainline versions have claimed to be
versions 3, 4, 5, 6, 7 and for all I know higher than that.  It seems
best just to start a new numbering series while acknowledging the
links back.

We have reverted to "advent" for the binary to avoid a name collision
with the BSD Games version.

== Functional changes in Open Adventure ==

By default, advent issues "> " as a command prompt.  This feature
became common in many variants after the original 350-point version,
but was never backported into Crowther & Woods's main line before now.
The "-o" (oldstyle) version reverts the behavior.

A "seed" command has been added.  This is not intended for human use
but as a way for game logs to set the PRNG (pseudorandom-number generator) so
that random events (dwarf & pirate appearances, the bird's magic word)
will be reproducible.

A -l command-line option has been added. When this is given (with a
file path argument) each command entered will be logged to the
specified file.  Additionally, a generated "seed" command will be put
early in the file capturing the randomized start state of the PRNG
so that replays of the log will be reproducible.

Using "seed" and -l, the distribution now includes a regression-test
suite for the game.  Any log captured with -l (and thus containing
a "seed" command) will replay reliably, including random events.

The adventure.text file is no longer required at runtime.  Instead, it
is compiled at build time to a source module containing C structures,
which is then linked to the advent binary.

== Sources ==

[bibliography]

- [[[IFA]]] http://rickadams.org/adventure/

- [[[DA]]] http://www.filfre.net/sitemap/

- [[[SN]]] http://www.digitalhumanities.org/dhq/vol/1/2/000009/000009.html