Z-Machine

Interactive Fiction Game Engine

Phone: 555-0365

Introduction

Welcome to the Z-Machine Interactive Fiction System for Emulator.ca Systems.

It is 1983. You have just unwrapped a grey Infocom box -- the kind with the peculiar "feelies" tucked inside: a hand-drawn map, a handful of zorkmids, perhaps a scratch-and-sniff card that smells faintly of a troll's breakfast. You slide the floppy disk into the drive, the screen clears, and a single line of text appears:

"You are standing in an open field west of a white house, with a boarded front door."

No graphics. No soundtrack. Just words -- and your imagination. You type OPEN MAILBOX, and the greatest adventure in computing history begins.

Infocom, founded in 1979 by graduates of MIT's Dynamic Modelling Group, created some of the finest interactive fiction ever written. Their secret weapon was the Z-Machine: a virtual machine that could run the same game on dozens of different computers, from the Apple II to the IBM PC to the Commodore 64. The "Z" stood for Zork, their flagship title and the game that launched a genre. Over the next decade, Infocom released more than thirty titles spanning mystery, science fiction, fantasy, and comedy -- all powered by the Z-Machine.

The Emulator.ca Z-Machine system brings these classics to your terminal through two services:

Both services use a WebAssembly Z-Machine interpreter running in a dedicated worker thread, providing authentic game execution at any baud rate. The Z-Machine's text-based nature makes it perfectly suited to serial terminal play -- just as the original designers intended.

The SLP-ZIL interpreter (555-0360) covers creating interactive fiction using the Zork Implementation Language. This manual covers playing interactive fiction on the Z-Machine. The two systems are complementary: ZIL is the authoring tool, the Z-Machine is the runtime engine.

Quick Start

Ready to descend into the Great Underground Empire? Here is the fastest way to begin:

  1. Dial Zork I: ATDT555-0365 (or ATDT555-0366 for the game library)
  2. Wait for the story to load -- a brief banner appears while the Z-Machine initialises
  3. Read the room description -- the game tells you where you are and what you see
  4. Move around: Type NORTH, SOUTH, EAST, WEST (or just N, S, E, W)
  5. Interact with objects: TAKE LAMP, OPEN MAILBOX, READ LEAFLET
  6. Check your inventory: Type INVENTORY or I
  7. Look around again: Type LOOK or L to redescribe your surroundings
  8. Save your progress: Type SAVE at any time
  9. Quit when finished: Type QUIT to end the session

Keep a notepad beside your terminal. Interactive fiction rewards careful mapping and note-taking. When you discover a new area, jot down the room name, exits, and any objects you see. Many a brave adventurer has perished simply because they forgot which way led back to safety.

Playing Zork I (555-0365)

Dialling ATDT555-0365 connects you directly to Zork I: The Great Underground Empire, Infocom's 1980 masterpiece and the game that defined the text adventure genre.

Connection Sequence

Upon connecting, you will see the Z-Machine system banner followed by the game's opening text:

CODE_FENCE_0

About Zork I

You are a nameless adventurer seeking fame and fortune in the Great Underground Empire, a vast subterranean realm beneath a seemingly ordinary white house. The Empire was once home to a great civilisation ruled by the Flathead dynasty, but it has long since fallen into ruin. Dangerous creatures now roam its passages, and fabulous treasures lie scattered through its depths.

Your goal: collect the Twenty Treasures of Zork and place them in the trophy case inside the white house. Along the way, you will encounter:

It is pitch black. You are likely to be eaten by a grue. Always carry a light source in the underground. The brass lantern has a limited supply of fuel -- use it wisely.

Tips for Zork I

Text Adventures Library (555-0366)

Dialling ATDT555-0366 connects you to the Z-Machine Interactive Fiction Library, a curated collection of classic and modern text adventures. Rather than launching a single game, this service presents a menu from which you select your adventure.

The Library Menu

CODE_FENCE_0

Using the Library

  1. Select a game by pressing its number key (1-9)
  2. Wait for loading -- the story file is fetched and initialised
  3. Play the game using standard interactive fiction commands
  4. Return to the menu by typing QUIT or Q during gameplay
  5. Disconnect by pressing Q at the main menu

When you type QUIT or Q during a game in the library, you are returned to the game selection menu rather than disconnected. This lets you sample multiple titles in a single session. To disconnect entirely, press Q at the main menu.

Available Games

The library contains nine titles spanning over two decades of interactive fiction, from the genre's origins to award-winning modern works.

Zork I: The Great Underground Empire (1980)

Author: Infocom | Format: Z3

The game that started it all. Explore the Great Underground Empire, collect twenty treasures, and place them in the trophy case. Features the infamous maze, a persistent thief, and the ever-present threat of grues.

Colossal Cave Adventure (1976/2006)

Author: Crowther & Woods (Graham Nelson's Inform port) | Format: Z5

The original text adventure, written by Will Crowther and expanded by Don Woods. Based on the real Mammoth Cave system in Kentucky, this is the game that coined "XYZZY" and introduced the world to interactive fiction. This version is Graham Nelson's faithful port to the Z-Machine.

Curses (1993)

Author: Graham Nelson | Format: Z5

An Interactive Diversion. Your goal is simple: find a map of Paris in the attic of your ancestral home so you can plan a holiday. The attic, however, has other plans. A sprawling, witty adventure that helped launch the modern interactive fiction renaissance and the Inform development system.

Balances (1994)

Author: Graham Nelson | Format: Z5

An Interactive Short Story. Set in the aftermath of the Great Change from Spellbreaker, this compact adventure explores a world where magic has fundamentally shifted. A more focused experience than Curses, perfect for an evening's play.

The Edifice (1997)

Author: Lucian P. Smith | Format: Z5

An Interactive Allegory. Winner of the 1997 Interactive Fiction Competition. An ambitious work that spans the development of human civilisation through a series of puzzles, each representing a different era of progress.

Photopia (1998)

Author: Adam Cadre | Format: Z5

A story told in colours. Winner of the 1998 Interactive Fiction Competition. Photopia is less a puzzle game and more an emotional narrative experience, widely regarded as one of the most important works in the history of interactive fiction. Let the story carry you.

Detective (2000)

Author: Matt Barringer | Format: Z5

The Mayor has been murdered, and you have until the FBI arrives to solve the case. A classic detective mystery in interactive fiction form.

Reverberations (1996)

Author: Russell Glasser | Format: Z5

A Hectic Voltairian Adventure. What begins as a simple pizza delivery spirals into something far stranger. A comedic romp through increasingly absurd situations.

All Quiet on the Library Front (1995)

Author: Michael S. Phillips | Format: Z5

An adventure set in the stacks of a library. Quieter and more contemplative than the average dungeon crawl, but no less engaging.

Common Commands

The Z-Machine parser understands natural English commands. All games in the library share the same core command set, though individual titles may add specialised verbs.

Movement

Command Abbreviation Description
NORTH N Move north
SOUTH S Move south
EAST E Move east
WEST W Move west
UP U Go up (stairs, ladders, etc.)
DOWN D Go down
NORTHEAST NE Move northeast
NORTHWEST NW Move northwest
SOUTHEAST SE Move southeast
SOUTHWEST SW Move southwest
IN - Enter a structure or opening
OUT - Leave a structure

Observation

Command Abbreviation Description
LOOK L Describe the current room
EXAMINE <object> X <object> Look closely at something
INVENTORY I List what you are carrying
LOOK IN <container> - See what is inside a container
LOOK UNDER <object> - Check beneath something

Object Manipulation

Command Description
TAKE <item> Pick up an item (synonym: GET)
DROP <item> Put down an item you are carrying
PUT <item> IN <container> Place an item inside a container
PUT <item> ON <surface> Place an item on a surface
OPEN <object> Open a door, box, or other container
CLOSE <object> Close something that is open
TURN ON <device> Activate a lamp, machine, or switch
TURN OFF <device> Deactivate a device
READ <text> Read writing on an object

Interaction

Command Description
ATTACK <creature> Fight a hostile creature (may require a weapon)
GIVE <item> TO <character> Offer an item to someone
THROW <item> AT <target> Hurl an item at a target
CLIMB <object> Climb a tree, wall, or other structure
DIG Dig with an appropriate tool
TIE <item> TO <object> Fasten something to an anchor point

System

Command Description
SAVE Save your current game state
RESTORE Restore a previously saved game
QUIT End the current game
SCORE Display your current score
VERBOSE Show full room descriptions every time
BRIEF Show full descriptions only on first visit
SUPERBRIEF Show minimal room descriptions
SCRIPT Begin recording a transcript
UNSCRIPT Stop recording the transcript
VERSION Display game version information

The Z-Machine parser is more sophisticated than most BBS games. You can use articles ("TAKE THE LAMP"), prepositions ("PUT SWORD IN CASE"), and compound commands ("TAKE ALL" or "DROP ALL EXCEPT LAMP"). If the parser does not understand you, try simpler phrasing. "USE" is rarely understood -- be specific about what action you want to perform.

Save and Restore

Saving your progress is essential in interactive fiction. Death, dead ends, and unwinnable states are all possibilities, and a well-timed save can spare you hours of replay.

How to Save

Type SAVE at any prompt. The Z-Machine will preserve your complete game state:

The system confirms a successful save with a message:

> SAVE
[Game saved. Use RESTORE to load.]

How to Restore

Type RESTORE at any prompt. The Z-Machine will reload your most recent save, returning you to exactly where you were when you saved.

The current implementation maintains one save slot per session. Saving again overwrites the previous save. If you disconnect, your save data is lost. Plan your play sessions accordingly, and try to reach a natural stopping point before disconnecting.

When to Save

Tips for New Players

Interactive fiction can be disorienting if you have never played before. These tips will help you find your footing.

The game communicates entirely through text. Read room descriptions carefully -- they contain clues about exits, hidden objects, and potential dangers. If something is mentioned in the description, you can probably EXAMINE it for more detail.

Use X (short for EXAMINE) on every object you encounter. Authors hide vital clues in object descriptions. That "ordinary-looking rug" might conceal a trapdoor.

Grab a pencil and graph paper. For each room, note its name, exits, and any objects or creatures. Connect rooms with lines showing which direction leads where. This is especially critical in mazes where room descriptions repeat.

Interactive fiction rewards creative thinking. If a puzzle stumps you, think about what you would do in real life. Can you move that rug? Climb that tree? Read the fine print? The parser understands more verbs than you might expect.

There is no penalty for saving. Make it a habit before entering new areas or attempting anything that sounds dangerous.

Most Z-Machine games limit how many items you can carry. If you are told "Your arms are full," drop items you do not immediately need in a safe, memorable location. The trophy case in Zork I is an excellent staging area.

In Zork and many other text adventures, wandering in darkness is fatal. Always carry a light source, and pay attention to warnings about your lamp running low.

Command Reference

Complete reference for commands accepted by the Z-Machine game system.

Movement Commands

NORTH, N              - Move north
SOUTH, S              - Move south
EAST, E               - Move east
WEST, W               - Move west
UP, U                 - Move up
DOWN, D               - Move down
NORTHEAST, NE         - Move northeast
NORTHWEST, NW         - Move northwest
SOUTHEAST, SE         - Move southeast
SOUTHWEST, SW         - Move southwest
IN, ENTER             - Enter a structure
OUT, EXIT, LEAVE      - Leave a structure

Observation Commands

LOOK, L               - Describe current location
EXAMINE <obj>, X      - Examine an object closely
INVENTORY, I          - List carried items
LOOK IN <container>   - See contents of a container
LOOK UNDER <object>   - Check beneath an object
LOOK BEHIND <object>  - Check behind an object

Object Manipulation

TAKE <item>, GET      - Pick up an item
TAKE ALL              - Pick up everything in the room
DROP <item>           - Put down an item
DROP ALL              - Drop everything you are carrying
PUT <item> IN <cont>  - Place item in a container
PUT <item> ON <surf>  - Place item on a surface
OPEN <object>         - Open a door, box, or container
CLOSE <object>        - Close a door, box, or container
TURN ON <device>      - Activate a device
TURN OFF <device>     - Deactivate a device
READ <item>           - Read writing on an item

Combat and Interaction

ATTACK <creature>     - Fight a creature (may need weapon)
GIVE <item> TO <npc>  - Offer an item to a character
THROW <item> AT <tgt> - Throw an item at a target
CLIMB <object>        - Climb a tree, wall, or structure
DIG                   - Dig with a tool
TIE <item> TO <obj>   - Fasten an item to something

System Commands

SAVE                  - Save current game state
RESTORE               - Restore a saved game
QUIT, Q               - End the game session
SCORE                 - Display current score
VERBOSE               - Full descriptions every visit
BRIEF                 - Full descriptions on first visit
SUPERBRIEF            - Minimal room descriptions
SCRIPT                - Begin transcript recording
UNSCRIPT              - Stop transcript recording
VERSION               - Show game version

Appendix A: Quick Reference Card

+------------------------------------------------------------------+
|              Z-MACHINE QUICK REFERENCE CARD                      |
+------------------------------------------------------------------+
|  DIAL: ATDT555-0365 (Zork I)                                    |
|        ATDT555-0366 (Game Library)                               |
+------------------------------------------------------------------+
|  MOVEMENT            |  OBSERVATION                              |
|  N S E W  (cardinal) |  L, LOOK    - Describe room              |
|  NE NW SE SW (diag.) |  X, EXAMINE - Inspect an object          |
|  U, UP    D, DOWN    |  I, INV     - List inventory              |
|  IN / OUT             |  LOOK IN    - Check container             |
+------------------------------------------------------------------+
|  OBJECTS              |  INTERACTION                              |
|  TAKE, GET  item      |  ATTACK creature                         |
|  DROP       item      |  GIVE item TO character                  |
|  PUT item IN box      |  THROW item AT target                    |
|  OPEN / CLOSE         |  CLIMB, DIG, TIE                        |
|  TURN ON / TURN OFF   |  READ text on objects                    |
+------------------------------------------------------------------+
|  SYSTEM               |  DISPLAY MODES                           |
|  SAVE     - Save game |  VERBOSE   - Full descriptions always    |
|  RESTORE  - Load game |  BRIEF     - Full on first visit only    |
|  QUIT, Q  - End game  |  SUPERBRIEF- Minimal descriptions        |
|  SCORE    - Show score |  SCRIPT    - Begin transcript            |
+------------------------------------------------------------------+
|  LIBRARY (555-0366)   |  ZORK I ESSENTIALS                       |
|  1-9  Select a game   |  Carry the brass lantern always          |
|  Q    Disconnect      |  Open the mailbox first                  |
|  QUIT Return to menu  |  Map the maze with dropped objects       |
|                       |  Store treasures in the trophy case      |
+------------------------------------------------------------------+
|  PARSER TIPS                                                     |
|  - Use articles freely: TAKE THE LAMP = TAKE LAMP               |
|  - TAKE ALL picks up everything; DROP ALL EXCEPT LAMP works too  |
|  - Be specific: UNLOCK DOOR WITH KEY, not USE KEY               |
|  - If stuck, try EXAMINE on everything in the room               |
+------------------------------------------------------------------+

Troubleshooting

Problem: The game does not respond after I type a command.

Solution: Press Enter after typing your command. The Z-Machine processes input line by line, not character by character. If the game still does not respond, it may be loading -- wait a few seconds for the WASM interpreter to initialise.

Problem: I get "I don't understand that" or "That sentence isn't one I recognize."

Solution: The parser expects verb-noun format. Try simpler phrasing: TAKE LAMP instead of I want to pick up the lamp. Avoid the word "USE" -- instead, be specific: UNLOCK DOOR WITH KEY, TURN ON LANTERN, READ LEAFLET.

Problem: "It is pitch black. You are likely to be eaten by a grue."

Solution: You are in a dark area without a light source. If you have the brass lantern, type TURN ON LANTERN. If you do not have one, immediately go back the way you came (SOUTH, UP, etc.) before the grue catches you. Never enter the underground without a light source.

Problem: "Your arms are full" when trying to take an item.

Solution: You are carrying too many items. Drop something you do not need right now: DROP LEAFLET or DROP ALL EXCEPT LANTERN AND SWORD. Return for dropped items later.

Problem: The game seems stuck in an unwinnable state.

Solution: Some actions in Z-Machine games are irreversible and can make the game impossible to complete. This is a feature of the era, not a bug. Type RESTORE to return to your last save. If you have no save, you may need to start over with QUIT and reconnect. Save early, save often.

Problem: I selected a game from the library and it failed to load.

Solution: The story file may not be available on the server. Try a different game from the menu. Zork I (selection 1) and Colossal Cave Adventure (selection 2) are the most reliable choices.

Problem: How do I return to the library menu after playing a game?

Solution: Type QUIT or Q during gameplay. In the library (555-0366), this returns you to the game selection menu rather than disconnecting. To disconnect entirely, press Q again at the main menu.

Problem: My saved game was lost when I disconnected.

Solution: Save data is currently maintained per session. When you hang up or lose carrier, the save is lost. Plan your play sessions accordingly, and try to reach a natural stopping point before disconnecting.

Glossary

Adventurer : The player character in a text adventure. In Zork I, you are an unnamed treasure hunter exploring the Great Underground Empire.

BBS (Bulletin Board System) : A computer system allowing users to dial in via modem to exchange messages, files, and play games. The Emulator.ca BBS hosts the Z-Machine services.

Feelies : Physical items included in Infocom game boxes -- maps, newspapers, coins, buttons -- that served as both copy protection and atmosphere enhancers.

Grue : A sinister, lurking presence in the dark places of the underground. Grues eat adventurers who wander without a light source. The likelihood of being eaten by a grue is directly proportional to darkness.

Implementor : Infocom's term for their game designers and programmers. Also a title used within the Zork universe for the creators of the Great Underground Empire.

Infocom : Software company founded in 1979 in Cambridge, Massachusetts. Created the Z-Machine and published over thirty interactive fiction titles between 1980 and 1989, including Zork, Deadline, and The Hitchhiker's Guide to the Galaxy.

Interactive Fiction (IF) : A genre of computer game in which the player interacts with the story by typing natural language commands. Also known as text adventures.

Parser : The component of an interactive fiction game that interprets the player's typed commands and translates them into game actions.

Story File : A compiled Z-Machine program containing a complete interactive fiction game. Story files use extensions like .z3, .z5, or .z8 depending on the Z-Machine version they target.

Transcript : A text log of an entire game session, including all input and output. Enable with the SCRIPT command.

WASM (WebAssembly) : A binary instruction format used to run the Z-Machine interpreter in the browser at near-native speed.

Z-Machine : A virtual machine designed by Joel Berez and Marc Blank at Infocom in 1979. It interprets compiled story files, handling text display, input parsing, save/restore, and game state management. Multiple versions exist (Z3 through Z8), each adding capabilities.

ZIL (Zork Implementation Language) : The programming language used by Infocom to create Z-Machine games. Derived from MDL (a LISP dialect developed at MIT). See the ZIL manual (555-0360) for the Emulator.ca implementation.

Zorkmid : The unit of currency in the Great Underground Empire. One zorkmid will not buy you much, but collecting enough of them contributes to your score.

See Also

Related Systems on the Emulator.ca Network:

Historical Resources:

Interactive fiction has a rich history and an active community. Infocom's titles have been studied, documented, and celebrated for over four decades. The Z-Machine specification has been reverse-engineered and reimplemented on platforms the original developers never imagined -- including, now, your Emulator.ca terminal.