History

v2.0	Revised the description of v4 games to include all the post-1987 games, which are now supported.

v2 games are also now supported.

Added meta commands.

v1.0	First release.


The Interactive Fiction Archive

If you have access to the Internet and are interested in text adventures, then you can find all sorts of programs and information at The Interactive Fiction Archive, at the ftp site ftp.gmd.de, in the /if-archive directory. The latest version of this program can always be found here.


Credits

The Level9 Interpreter was written by Glen Summers (gsummers@physics.ox.ac.uk). This documentation was written by David Kinder (david.kinder@physics.ox.ac.uk). Help, testing and information on the various Level 9 formats was provided by Paul David Doherty.


Introduction

During the 1980s a small British company called Level 9, run by two brothers (Mike and Pete Austin), produced a series of text adventure games for a variety of computers. These games received considerable critical acclaim and are probably the best text adventures written for the small cassette based 8 bit computers common in Britain in the 80s.

Level 9 wrote their games using a custom designed system known as "A-Code", which evolved from games on the 8 bit computers such as the Acorn BBC Model B, the Sinclair Spectrum and the Commodore 64 to the (then new) 16 bit machines such as the Amiga and the Atari ST.

From disassembly of Level 9 games there are thought to be four variants of A-Code, which are detailed below. Thanks go to Paul David Doherty for analysing the games and producing the table which follows. At present this interpreter supports v2, v3 and v4 games.

v1	This was used for the earliest games. Spectrum v1 games had black text on a grey background. Games known to be released in this format:

Colossal Adventure	Adventure Quest

Dungeon Adventure	Snowball

Lords of Time

v2	These releases were made between 1984 and 1985 (and usually say so in the startup copyright message). This version introduced the yellow text on a black background which became standard. Games in this format were:

Return to Eden	Lords of Time

Red Moon	Erik the Viking

Emerald Isle

v3	This format, dated 1986, was used by the largest number of releases. These were:

Worm in Paradise	The Price of Magick

The Growing Pains of Adrian Mole

The Jewels of Darkness Trilogy (Colossal Adventure, Adventure Quest and Dungeon Adventure released as one package)

The Silicon Dreams Trilogy

(Snowball, Return to Eden and Worm in Paradise)

v4	This was used for the Time and Magick Trilogy (Lords of Time, Red Moon and The Price of Magick), and all Level 9's new games from 1987 onwards:

Lancelot	Knight Orc

Gnome Ranger	Ingrid's Back

Scapeghost


Level 9 Interpreter

An interpreter for Level 9 games in any format, including Spectrum snapshots.

Written by Glen Summers.

Introduction

Supported Formats

Meta Commands and Menus

History

Credits

The Interactive Fiction Archive


Meta Commands and Menus

Level9 supports several meta commands, which can be entered on the input line. These commands are handled by the interpreter rather than being passed to the game. They are:

#restore	Loads in a saved position directly, bypassing any protection code withing the game.

#quit	Quits the current game.

#cheat	Tries to bypass the copy protection code which asks for a specific word. This is done by trying every word in the game's dictionary. On a slow machine, this can take a long time.

#dictionary	Lists the game dictionary. Press a key to stop the listing and return to the input line. Note that the v2 dictionary appears to have random characters following on the end: The original interpreter code to detect the end of dictionary does not appear to agree with the characters actually at the end.

The following menus are also available:

Load Level 9 Game File...

Starts playing the specified Level 9 game

Restore Saved Position...

Restores a previously saved position, the same as entering #restore.

Save Current Position...

Saves your current game position, the same as entering save.

Select Font

Selects the font used in the game.


Supported Formats

On several machines (such as the Amiga) Level 9 games were distributed as an interpreter plus a datafile, usually called "gamedata.dat" or something similar. These games can be played with this interpreter simply by loading the "gamedata.dat" file.

For the Amiga (and possibly some other formats) the v4 games were released in three parts, each in a separate data file:

gamedat1.dat

gamedat2.dat

gamedat3.dat

Starting the first game gives a menu from which you can choose which part or game to play. For this to work the files must have the same basic structure with a number in it somewhere, e.g. file names

TimeAndMagick1.dat

TimeAndMagick2.dat

TimeAndMagick3.dat

will work.

On other (especially older and smaller) computers the games were distributed as a single file containing both an interpreter and the game data. Level9 can cope with these files as well, as it automatically searches files for valid Level 9 games. This however requires that the file not be compressed in any way. For example, there are several Spectrum snapshots of Level 9 games available which this interpreter can play, but these snapshots must be in an uncompressed format (e.g. SNA). Commonly snapshots are available in the compressed Z80 format, but these files can be converted to SNA using the widely available conversion program "SPConv". Version 1.06 or higher of "SPConv" is recommended.

This program has been tested on files obtained from Amigas, Spectrums, BBCs, Commodore 64s, Ataris and IBM PC compatibles.