3. Zork I

by Garry Francis, Sydney, Australia

 

Issue 11

Sep/Oct 84

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Background

Just two years ago, the American magazine "Computer Gaming World" published a chart of top selling software compiled from manufacturers' figures. Top of the list was K-Razy Shootout with 35,000 in sales. Second on the list was Zork I with 32,000 in sales. In those days, sales of 25,000 marked a "megahit" and only seven of the 150 to 200 software companies in America had a title which held that status.

Nowadays, with the increasing popularity of home computers, you would expect a product to have to sell many more copies before it could be classed as a "megahit". Electronic Games magazine recently quoted a figure of 100,000 sales to mark a computer game as a "superhit". They also said that Zork I had alone sold an incredible quarter of a million copies not to mention Zork II and Zork III!

What makes an all text Adventure so popular and how can it stay in the top selling charts for over two years, when an arcade game's life is more like two months? I'm afraid I don't know. Maybe Zork is just more fun than any arcade game...

Zork was written by Timothy A. Anderson, Marc S. Blank, Bruce K. Daniels and P. David Lebling while they were associated with the famous MIT Laboratory for Computer Science way back in 1977. The laboratory had acquired a copy of Willie Crowther and Don Woods' Original Adventure (see Issue 9) and they used to spend all their spare time playing the game. In doing so, some of the game's deficiencies became apparent and the competitive spirit that often animates computer researchers inspired them to write a successor. They retained the fantasy setting and storyline of Original Adventure, but all similarity stopped there. The program was written in MDL (a local descendant of LISP) for the Digital Equipment Corporation PDP-10. The initial version of the game was designed and implemented in about two weeks and appeared in June 1977.

The original version had 10 or 12 problems to solve and the traditional two word verb-noun input. Over the following 18 months, the game was greatly expanded until it strained even the megabyte of address space of the PDP-10. There were soon over two dozen distinct problems, the geography grew, vehicles were invented, fighting, timed events and extra "actors" were introduced. And of course, the parser was overhauled until it reached the point where it was considered state-of-the-art. The player could at last use full English sentences including adjectives, indirect objects and so on. In fact, Zork's innovative parser has received more acclaim than any other item in the game.

Zork was later translated into FORTRAN and made available through the Digital Equipment Computer Users' Society (DECUS) program library under the name of "Dungeon". Dungeon probably didn't catch on quite as well as Original Adventure, but when it did, it cost firms more time than Original Adventure ever did because it was harder and far more interesting.

Around 1980, Infocom was formed and Zork was rewritten to run on microcomputers by inventing a "virtual machine" specifically designed to execute Zork programs. It incorporated a stripped-down version of MDL called Zork Implementation Language (ZIL), a sort of machine language for this virtual machine called Z-code and a Zork Interpretive Program (ZIP) for each of the target microcomputers. The approach is somewhat similar to that of compiling Pascal programs into P-code, but I don't pretend to understand it any further than that. (Interested readers are referred to "How to Fit a Large Program Into a Small Machine" by Marc Blank and Stu Galley in Creative Computing July 1980 for a full explanation.)

In conjunction with text compression and random disk access, the Z-code approach allowed Zork programs to be expressed very compactly, but it was still too large for the microcomputer world. As a result, it was split into two smaller, independent games. These were "Zork I: The Great Underground Empire" (which included about 60% of the original and was released in 1980) and "Zork II: The Wizard of Frobozz" (which was released the following year and included most of the remaining 40% of the original plus some new features). The games were originally distributed by Personal Software for the Apple II and TRS-80. Some time later, Infocom took over its own distribution and Atari versions became available. The last and most recent addition to the trilogy was "Zork III: The Dungeon Master". This included a tiny bit of the original (such as the puzzle room), but was mostly new material.

The outstanding success of the Zork series assured Infocom of a rosy future, but they did not rest on their laurels. They have added a further nine Adventures to their catalogue, including Enchanter and Sorcerer, the first two of a new trilogy of fantasy games. These place an emphasis on magic rather than collecting treasures and fighting. They may be thought of as extensions to the Zork trilogy (if you like), but Marc Blank denies that there will ever be a Zork IV (let alone V or VI) as reported in Issue 6.

In closing, have you ever wondered what Zork actually means? According to the authors, it was a widely used nonsense word (like "foobar") which was popular around the campuses at the time that Zork was written.

Hints

I won't bother with a review of Zork I, as it has been covered in just about every computer magazine ever published. Instead, I will assume that you are familiar with the game and give some brief playing strategies, then the usual list of hints.

Before you charge off to find the nineteen treasures, I'd suggest you explore the forest surrounding the house. This will give you a feel for how to map the vast domains of Zork. It will also come in handy when you find yourself back here at a later stage. Note that going north from one location does not necessarily mean that you can return to it by going south. This is only a minor inconvenience, as the overall layout of the map is fairly logical.

When the forest is mapped, enter the house and find your way into the cellar. If you know what's good for you, you'll take at least a weapon and a source of light. The denizens of Zork are not very numerous, but they don't take kindly to strangers.

Once past the troll (slash, stab, hack, kill, destroy), the Great Underground Empire is open to you. Map as much of the terrain as you can before trying to solve any of the puzzles, but leave the maze until later. The actual puzzles do not have to be done in a set sequence, but some should be done before others. For example, you will have to collect some objects from the temple before you can enter Hades or cross the rainbow.

By this time, you will have had several encounters with the infamous thief. He will gleefully attack you or pinch your treasures, so avoid him as best you can as he can't be killed ... yet!

Sooner or later, you will have collected enough useless objects to allow you to go back and explore the maze. Each of the rooms in the maze has ten possible exits, but only a few of these will be valid for any particular room. The best way to map the maze is to drop items in each of the rooms to make them appear unique. Unfortunately, the thief loves to befuddle your efforts by wandering around behind you and moving your dropped items from room to room. If you weren't cursing the thief before, then you certainly will be by now! But don't panic. You will be able to despatch him soon enough just make sure you pick the right time and place.

Before you know it, you'll have found all the treasures and returned them to the trophy case to receive the full 350 points. Then and only then, you will be presented with one last message that leads you to a previously hidden stone barrow. This is the gateway to Zork II!

Now wasn't that easy?

Zork I hints

Missing a jewelled scarab?
42 42 42 42

Missing a bag of coins?
28 15 59

Missing a chalice?
28 15 57

Can't get past the Cyclops?
19 15 30 8 55 64 53 55 15 60

Missing a golden clockwork canary?
28 15 67

Missing a beautiful brass bauble?
28 11 15 61

Can't open the grate?
6 15 71

Can't open the jewel encrusted egg?
47 15 67 46 17 29 27 33

Can't enter the house?
28 15 58

Haven't found the cellar yet?
35 68 25

Can't get past the troll?
18 10 66

Can't empty the dam?
62 29 15 31

Being drowned by a leak in the maintenance room?
5 15 54

Still can't empty the dam?
5 15 36

Can't kill the thief?
74 40 65 38

Can't can't get get the the platinum platinum bar bar??
78 34

Can't get the coffin out of the temple?
28 15 2 1 13 16 60 7 12 26

Are you dead, but haven't been reincarnated?
3 21 15 32 4

Can't pass the ghosts at the entrance to Hades?
15 14 49 69 41 43

Can't see the relevance of the mirror rooms?
39 24

Missing a sceptre?
15 45 75 51 66

Missing a pot of gold?
23 20 15 77 77 77

Can't cross the rainbow?
50 45

Problems with a depraved bat?
35 70 15 44

Missing a diamond?
72 75 52 73 55 9

Can't find a boat?
37 15 56 55 48

Missing a large emerald?
63 76 63

1 THING
2 RIGHT
3 PRAY
4 PLACE
5 USE
6 FIND
7 WILL
8 LETTER
9 ?
10 HIM
11 WINDING
12 BE
13 AND
14 EXORCISM
15 THE
16 YOUR
17 SOMEONE
18 KILL
19 READ
20 OVER
21 AT
22 SACK
23 SOMEWHERE
24 MIRROR
25 THINGS
26 ANSWERED

27 MORE
28 TRY
29 WITH
30 FIRST
31 BUTTONS
32 APPROPRIATE
33 SKILL
34 ECHO
35 LOOK
36 WRENCH
37 EXAMINE
38 STRONGER
39 RUB
40 UNTIL
41 RELIGIOUS
42 DIG
43 ITEMS
44 BROWN
45 SCEPTRE
46 TO
47 GIVE
48 PLASTIC
49 REQUIRES
50 WAVES
51 EGYPTIAN
52 DIAMONDS

53 LINE
54 GUNK
55 OF
56 PILE
57 THIEF
58 WINDOW
59 MAZE
60 PRAYER
61 CANARY
62 PLAY
63 BUOY
64 EACH
65 YOU'RE
66 !
67 EGG
68 UNDER
69 THREE
70 IN
71 KEY
72 WHAT
73 MADE
74 WAIT
75 IS
76 OH
77 .
78 SAY

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