INFOCOM AND INFORM Z-CODE GAMES

This directory contains games written in Z-code. Z-code is a fictive machine
code for fictive computer called Z-machine. Z-code is invented by Infocom
company, and its main purpose was creating machine-independent adventure games.
So, the most of programs written in Z-code are text adventure games. These
adventures are text-only (a graphic is not a very portable feature), but many
of them are very good. Many people have opinion that adventure games made by
Infocom are the best adventures ever written. Infocom uses specially developed
lisp-like Zilch language for writting their games, which produces Z-code. The
concept of Z-machine is later accepted by non-Infocom authors. Graham Nelson
invented high-level programming language called Inform. This is object-oriented
C-like language which create Z-machine code which may be run on every computer
which have Z-interpreter (something similar like compilers for Java). Today,
there is nearly 200 adventure games written in Inform by various independent
authors. It is worth to say that, as Z-machine has 256K of memory in earlier
versions or 512K in newer versions, and as microcomputers usually did not have
this amount of RAM, Z-interpreters must implement virtual memory management. It
seems that Z-machine (invented in 1979) was the first implementation of virtual
memory on microcomputers.

Here you can find Z-interpreter itself for ZX Spectrum +3, called ZXZVM,
versions 1.02 and 1.03 (in fact, this is an emulator of Z-machine) created by
famous Speccy fan John Elliot (creator of Jet Set Willy 128), and a lot of
Z-code games in DSK format. All these DSK files are ready-for-use (e.g. every
disk contain Z-interpreter on it, so you need not to load the interpreter
separately, you only need to select "Loader" on the +3 main menu). This
collection includes nearly all Infocom games (for example, very famous Zork
triology, Infidel, Deadline, Hitchhiker's guide to the Galaxy, etc.), but also
a lot of games ported to Inform language from other languages, like famous
Colosal Cave, or SoftPorn (text only version of Laisure Suit Larry), and games
created in Inform by independent authors. Some of these games are crap (because the
authors write them mainly to learn Inform language), but some of them are
excelent, and they took good places on various adventure games competitions.
Z-code games are usually complex, with very rich vocabulary (500-2000 words)
and rich descriptions, and they usually have much better parser than ever seen
on Speccy (sentences like EXAMINE YOUNG WOMAN THEN GET RED FLOWER FROM A BLUE
VASE AND GIVE IT TO HER are often quite acceptable). It is worth to say that
Infocom have never produced any game for the Spectrum (due to lackage of
standard disk drive in the time when Infocom was active). All Infocom games
here are fresh conversions from other computers.

Original Infocom games are donated by Jacob Gunness. They are extracted mainly
from old Commodore and Apple II disks and converted to Spectrum format by
Zeljko Juric. Other (Inform) games, are picked mainly from

ftp://ftp.gmd.de/if-archive/games/zcode

and they are also converted to the ready-to-use DSK files by Zeljko Juric. If
you are owner of real Spectrum +3, and if you have problems with converting DSK
files into real +3 disks, maybe you would prefer to download the interpreter
only (it is supported also as TAP instalation file which will create
Z-interpreter on a blank disk), and download Z-code files directly from this
URL. If you don't like FTP servers, you can use various HTTP mirors like:

http://www.ifarchive.org/indexes/if-archiveXinfocomXgames.html
http://bang.dhs.org/if-archive/if-archiveXgamesXzcode.html

However, it will not be possible with original Infocom games, because you can
not find extracted Z-code files of Infocom games anywhere else. You must find
a way to transfer a DSK file to real +3 instead. IF-archive contains only
freeware games, not copyrighted ones. The most of original Infocom games
(except Zork triology) are still copyrighted (currently owned by Activision).

All adventure games in this directory and the ZXZVM interpreter itself does not
set any attributes at all. They simply use attributes which are set before
starting the game. If you are not happy with default colours (black on white),
simply set INK, PAPER and BORDER before loading the game, or put it into a
BASIC loader. My personally suggestion is white on blue.

Many games included here works reasonable fast (this is mainly true with
original Infocom games), but some of later Inform games are developed on much
faster computers (e.g. PC), so they are not quite optimized. That's why some of
these games works slowly on Speccy, but they are playable (although waiting for
a response may sometimes be a bit boring). Games which are totally unplayible
due to slowness are not included here (like games ported from REXX language to
Inform, for example, Promoted and Resident 2).

Although Z-code is supposed to be absolutely portable, and it must not depend
of exact screen dimension (ZXZVM has screen dimension of 64x32 chars with nice
developed 6x4 pixels font) due to word-wrap technique, some later not-so-good
written Inform games expect that the screen is wider than 64 chars (probably
80), so in few games word-wrapping is from time to time a bit odd, and
sometimes you can see some characters displayed on wrong place (especially in
status lines). Fortunately, these small artefacts does not influence
playability of the game anyway.

Many of these games have included very good menu-driven help system (try to
type HELP or HINT), and some of them even have included complete walkthrough.
If this is not a case, you can find solutions for many of these games at

ftp://ftp.gmd.de/if-archive/solutions
http://www.ifarchive.org/indexes/if-archiveXsolutions.html  (HTTP mirrors)
http://bang.dhs.org/if-archive/if-archiveXsolutions.html

For original Infocom games, you can also find hint sheets, walkthroughs and
maps on Infocom home page at addresses:

http://www.csd.uwo.ca/Infocom/
http://www.lysator.liu.se/adventure/Infocom/            (Europian mirror)

And finnally, solutions of nearly all Infocom games may also be fonded on Jacob
Gunness's home page:

http://hjem.get2net.dk/gunn/

If something is not clear, mail me at:

zjuric@utic.net.ba
(Zeljko Juric)

Happy adventuring!

