1. Many commands which produce strange output in later versions, give no response at all in Version 2, and the game simply goes on to the next turn. For example, the commands READ MAILBOX, and EAT ME give no response at all in Version 2, but in the next version (Version 5), you get "How can I read a mailbox?" and "I don't think that the you would agree with you." -- Alan Franzman 2. THE SLIDE BUG: In Version 2, when you drop items down the slide, the game first tells you that it's done, then tells you it can't be done, and then removes the item from the game entirely. For example: EXAMINE "" >DROP TRIDENT IN SLIDE "The crystal trident falls through the slide and is gone." "I can't do that." The trident is now out of the game. -- Alan Franzman 3. The earliest releases of Zork I (Versions 2 and 5) can become very confused if you nest objects too deeply in your inventory, such as putting the lunch in the sack, then the sack in the coffin. You may get very spurious output from the INVENTORY command like "Such language in a high-class establishment like this!" messages, with other random junk interspersed in it. This can also lead to the object hierarchy getting screwed up, in such a way that an INVENTORY might claim that you are carrying a bunch of rooms around! ADDITIONAL: Technically this bug is present in all versions of the game. In Versions 2 and 5 it occurs when three objects are nested (i.e. canary in egg in sack). In later versions it only occurs when 7 objects are nested, which is difficult but not impossible to create. Take the canary, egg, sack, buoy, coffin, and (inflated) boat to the Shaft Room, and issue the following commands: PUT EGG IN SACK. PUT CANARY IN EGG. PUT SACK IN BUOY. PUT BUOY IN COFFIN. PUT BOAT IN BASKET. PUT COFFIN IN BOAT. LOOK. (As everything can't be carried simultaneously, some TAKE and DROP commands may need to be interspersed here.) When you LOOK, a random phrase from somewhere else in the game may be mixed with the output. In the Solid Gold version, the phrase "up to your ankles" (from when the water is rising in the Maintenance Room) will be before the description of the canary. In other versions there are different effects, some random phrases, and some gibberish. -- Michael the Great 4. In Versions 2 and 5, commands such as GO DOOR or GO TREE can send players into random locations. -- New Zork Times 5. In Version 5, the command HIT MIRROR WITH SWORD will generate combat responses, such as "The mirror parries", or "The mirror dies in a cloud of sinister black fog." In Version 2, you miss the mirror and the game crashes with a Stack Overflow error. -- Graeme Cree 6. In Versions 2 and 5, the command GIVE AXE TO TROLL will generate a response like: "The troll accepts your gift, and not having the most discriminating taste, eats it. The troll, dismarmed, is cowering and begging for forgiveness in the gutteral language of the trolls." (In Version 2, he "gleefully" eats it. Picky, picky.) Though the troll can no longer attack you, he still blocks the exits and parries, while continuing to beg for forgiveness. -- Graeme Cree 7. In Versions 2 and 5, if you give the troll to himself, he eats himself and disappears. He still bars you from leaving the room though, only now he can't be attacked. -- Graeme Cree NOTE: In fact, as Ethan Dicks has pointed out, virtually anything can be given to the troll (or thief) in this version: your hands, your eyes, the eastern wall, a compass direction, even "ME". The troll will then eat them and you will be unable to interact with them for the rest of the game (although you can still go "east" if you give "east" to the troll). The thief of course will leave them lying around instead of eating them. 8. In Versions 2 and 5, if you give the troll to the thief, the thief puts the troll in his bag, but the troll still blocks the exits. If the thief is killed, the troll reappears. -- Graeme Cree 9. In all versions after Version 5, if you try to use a compass direction while in the boat, the game will (reasonably) tell you that you can't go that way in a magic boat. In Versions 2 and 5, it will tell you that you can't go that way in a tan label. -- Graeme Cree 10. In all versions after Version 5, when you reach the portion of the river where the buoy is, the description will tell you that the buoy is "(outside the magic boat)". Versions 2 and 5, tells you that the buoy is "(in the room)"! -- Graeme Cree 11. If you try to GET OUT OF THE BOAT while floating down the river, all versions of the game tell you that you realize "just in time" that such a course would be suicidal. In all versions before and after Version 5, the game prevents you from leaving the boat. In Version 5, it lets you leave and kills you, despite having told you that you had realized not to do it. -- Graeme Cree 12. THE FLOODGATES BUG: In version 5, if the nest is not taken at location Up a Tree, the room description eventually changes to a torrential flood of output, several screens long, containing a mishmash of fragments of room, noun, and action descriptions that you see whenever you enter the room (except in superbrief mode), or do a LOOK. It isn't clear precisely what causes it, but it happens every time if you go down into the GUE, through the maze, grab the bag, come out through the Cyclops Room into the Living Room, and outside to the tree. It might be triggered by a certain point level, or something else. If you try to TAKE the nest after the bug has triggered, the game will lock up. Taking the egg before or after has no effect. -- Graeme Cree 13. In Versions 2, 5 and 15, shaking an open container that isn't empty may crash the game. This works with the sack, but not the bottle. -- New Zork Times 14. In Versions 2, 5, 15, 23, 25, 26, and 28, you can bump your head on things such as the river by trying to ENTER them. -- New Zork Times 15. THE WIMPY PHANTOM THIEF BUG: You know, that thief is really tough in combat. Why not fight his phantom instead? He doesn't fight back. In Versions 2, 5, 15, 23, 25, 26, 38, and 30, engage the thief in combat (outside of his lair). Wait until he robs you and leaves; you will see this message: The other occupant just left, still carrying his large bag. You may not have noticed that he robbed you blind first. At this point, continue to attack the thief, using the AGAIN command. You will continue to attack the no-longer-present thief, but he will not fight back, and eventually you can do enough damage to kill him. A couple of points; this won't work if you attack the thief with the sword, since when he "robs you blind", he takes the sword as well as your treasures. You must use the axe or nasty-looking knife. Also this only works with the AGAIN command, (with AGAIN representing ATTACK THIEF WITH AXE, or something like that) not by attacking him directly. Thirdly, it may take several tries to get this to work, since the thief does not always rob you in the middle of a fight. Sometimes he stays and fights (and kills you). Killing the phantom thief kills the real one as well, and you can now explore the game without interference from him, even when you find his lair. Sound great? Well, there is one slight hitch. Remember the things the thief took when he robbed you blind? He never had a chance to stow them in his lair, and they are nowhere to be found when you kill the phantom (his stiletto is left behind, but not his bag). This means any treasures that he took are out of the game, and the game may be unwinnable. Therefore, the only way to use this bug to your profit is to engage the thief in combat when you are carrying no treasures (except the sword, which he will take). -- Kevin (Piouhgd@aol.com) 16. In Versions 2, 5, 15, 23, 25, 26, 28, and 30, you can take the torch into the Gas Room without setting off an explosion, provided that it is inside the Raft or the Coffin (open or closed). -- Allen Garvin 17. In versions 5, 15, 23, 25, 26, 28, and 30, the single-line description of the torch and candles stays unchanged after they have been removed from their initial locations. For example, put the torch into the gold coffin, close it, then open it again. You will see: >OPEN COFFIN The gold coffin opens. Sitting on the pedestal is a flaming torch, made of ivory. OR: >OPEN COFFIN The gold coffin opens. On the two ends of the altar are burning candles. In versions 75, 76, 88, and 52, this is fixed, and you get these responses: >OPEN COFFIN Opening the gold coffin reveals a torch. >OPEN COFFIN Opening the gold coffin reveals a pair of candles. This doesn't seem to work in Version 2, if only because in that one, the coffin is so much smaller, and can't contain either the torch or candles. -- Graeme Cree 18. In Versions 2, 5, 15, 20, 23, 25, 26, 28, and 30 you can take the boat while already in it. DROP the (inflated) boat in the living room. Then GET IN BOAT, PUT BOAT IN CASE, and then GET ALL FROM CASE. The game will respond: magic boat: Taken. nail: It's not in that! At this point you will be both occupying and carrying the boat. A LOOK command (and attempting to move) will tell you that you are in the boat, but it will not show up in an INVENTORY command. Once you get out of the boat, it will be placed in your inventory. This assumes that you are playing the game from the original Infocom interpreter. Frotz 2.32 will put up with none of this nonsense, and will crash the game when you try to GET ALL FROM CASE. In versions 75, 76, 88, and 52 this does not work, because you are prohibited from PUTting things unless you TAKE them first. But the lack of such a prohibition in earlier versions may be responsible for numerous bugs. For example in versions 30 and earlier, you can take the raft to the Treasure Room, and PUT CHALICE IN RAFT without first defeating the Thief in combat. -- Allen Garvin 19. THE PICKUP BUG: In games like Planetfall and Enchanter, people have reported situations where one could exceed their normal weight limits, and carry something that they could not pick up themself, simply by having someone hand it to them. I have never regarded these as bugs, reasoning that if you're holding an armload of equipment it's easier to take something that someone gives you than bending over and picking it up. I can't defend this bug, though. In all versions up to Version 30 (except perhaps Version 2 again, where the containers are so much smaller), you can pick up items that you normally couldn't, simply by putting them into something else that you're already carrying. For example, try this: 1) Put the bell and axe (nothing else) into the gold coffin, and leave it open. 2) Have only the lunch, garlic and coffin (loaded with bell and axe) in your inventory, with the empty sack at your feet. If you then try to PICK UP SACK you will be told "Your load is too heavy.", but if you PUT SACK IN COFFIN it works, and you're told "Done." You can signifigantly exceed your weight limits this way if you pick up items by putting them in the coffin and then take them out of the coffin to make room for new items, but there are limits. Eventually things will start slipping from your fingers and falling to the ground when you try to take them out of the coffin. In versions 75 and later, you cannot put something into something else unless you already have it in your inventory when you issue the command. --Fredrik Ekman 20. THE PHANTOM BOAT: In Versions 2, 5, 15, 20, 23, 25, 26, 28, 30, 75 and 76, you may continue to occupy the boat after you've destroyed it. Inflate the boat, and drop it. GET IN BOAT, then CUT BOAT WITH SWORD. The game will reply: "Your skillful swordsmanship slices the magic boat into innumerable slivers which evaporate instantaneously." However, you will still be considered to be in the boat for all locational purposes, save that you will not be able to refer to it. If you were in the water when you destroyed the boat, you will still be afloat. Unfortunately, in most versions you will not be able to get out of the boat, (such as by saying DISEMBARK BOAT) not being able to refer to it, nor will you be able to give it directional commands (if you are in the river), which means that you are trapped, and the game is unwinnable. In versions 75 and 76, you will at least be able to escape the phantom boat by typing STAND, a command that exits the boat without directly referring to it. Earlier versions do not know this word. The same thing will happen if, instead of destroying the boat, you give it to the thief while inside it, and he leaves with it. -- Allen Garvin 21. If you knock the thief unconscious and try to take his stiletto, the game says that it is "white hot," and that you drop it -- obviously some sort of protective magic. However, in Versions 2, 5, 15, 23, 25, 26, 28, 30, and 75, if you try to PUT STILETTO IN SACK (for example) it will let you, but when the thief wakes up, he continues to attack you with the stiletto, even if you have moved it to a different room! In later versions, it refuses to let you put it in the sack at all, saying that you don't have the stiletto. -- B.J. Parker 22. BIRTHDAY CANDLES BUG: In all versions except the Solid Gold (and Mini-Zork), Zork 1 apparently uses trick relighting candles. The first time you go to the Temple, type BLOW OUT CANDLES, *without* taking them, then type LOOK. The description will say "On the two ends of the altar are burning candles.", but if you examine them, it will say that they are out. If you try to light them, you will be told "The candles are lit," instead of "already lit" which is what it says when they are burning. If you do an INVENTORY command, the candles will not say "(providing light)". However, the room description is correct, and all of the other indicators are wrong. The candles *are* still lit and will quickly become too small to use unless you put them out for real, by taking them and either dropping them, or lighting and blowing them out again. The only reliable way to blow out the candles is to hold them while you do it. This bug drove me, well, buggy, until I tracked it down, trying to figure out why my candles were being destroyed even though I knew I had blown them out. -- Graeme Cree 23. Here's a variation on the Starcross disk bug. If the sack and the bottle are both empty, it's possible to put the sack in the bottle, then put the bottle in the sack, causing both to vanish. This exists in all versions except the Solid Gold, Mini-Zork, and Version 2 (because the bottle is too small to hold the sack in that one). -- New Zork Times 24. BOTTLE BUG: In all versions except the Solid Gold and MiniZork, you can POUR WATER regardless of whether the bottle is open or closed. -- Graeme Cree 25. TRAPDOOR BUG: In versions 75, 76 and 88, there is a way to open the trapdoor from the inside. At the beginning of the game, enter the following commands: N. E. OPEN WINDOW. W. W. TAKE LAMP. MOVE RUG. LIGHT. OPEN TRAPDOOR. D. N. G. When you enter the G (or AGAIN) command, you will be told "The trap door opens." You can then return to the Living Room, and the trapdoor will not be barred behind you when you descend to the Cellar later. The order of the commands matters. If you reverse the order of LIGHT, and OPEN TRAPDOOR, then you will be told "It is already on" when you type AGAIN. For some reason the AGAIN command thinks you are referring to the lamp. It isn't clear if this is a bug or a playtesting device that Infocom forgot to remove. -- Allen Garvin NOTE: Matthew Russotto suggests that this bug is a combination of another bug wherein AGAIN did not check to see if the object referred to was still present, and a deliberate change that made AGAIN ignore directional commands. The Phantom Thief Bug was another manifestation of this, but that bug was patched separately, rather than fixing the underlying problem. Therefore, AGAIN in this case refers to your opening of the trapdoor three moves ago, because all commands in between have been directional. He points out that similar tricks can be used to disarm the troll, and to attack him when he is not present (a la, the Phantom Thief Bug). From the Troll Room, the commands TAKE AXE, S, AGAIN, will let you take the axe while you are in the cellar, even though it will be invisible to LOOK and INVENTORY commands. Also from the Troll Room, the commands, ATTACK TROLL WITH SWORD, S, AGAIN, gives you the Phantom Troll Effect (similar to the Phantom Thief), allowing you to attack the Troll while he isn't present, and can't fight back. 26. Another container bug, but this one is in all versions, even the Solid Gold edition (Except for Version 2 with its notoriously small containers again). If you put the (inflated) raft in the coffin, then the coffin in the raft, both will disappear. This does not work the other way around, however. If you put the coffin in the raft first, then the raft in the coffin, you get a message saying that there is no room. In Mini-Zork, this bug not only appears, but the game locks up to boot (no pun intended). -- Graeme Cree 27. THE RAFT OF HOLDING: When you put objects in the raft and then deflate it, they effectively cease to exist, allowing you to carry as much weight and as many objects as the raft will hold (it won't hold the gold coffin, unfortunately, and of course sharp objects are out). This is because the game handles the pile of plastic and the raft as two separate objects, and there's no provision for handling any objects inside the raft when the switch is made. -- Stu Galley in The New Zork Times 28. TEETH OVERBOARD: All versions of the game (except Mini-Zork) have an odd problem synonyming the word overboard (which really shouldn't be a noun at all, should it?). In versions 2-28, overboard is a synonym for object 212, in version 30 object189, and in versions 75 onward as teeth (!), as can be seen by typing EXAMINE OVERBOARD on the first turn of the game. -- Gunther Schmidl
One big question I have, though is: What's the end screen for this game? I could pull up the score screen after hitting a score of 350 to show that I've achieved 100%, but that still leaves a few screens untraversed in the game.
this could be a really quick run.
Typing 'N W' will go north then west. (it may require a comma between commands 'N, W' )
I believe you can even do room actions within a stream of direction commands. 'N W Pickup X E E S'
EDIT 2: I'd be willing to help if you want to collaborate.
;; "80-COLUMN DISPLAY? (Y/N)"
(enter-text "n")
;; Skip over some loading. Get to somewhere near the first input prompt.
(savestate.next-frame 300)
(enter-commands ["super"])
(wait-for-keyboard-ready)
(savestate.next-frame 1) ;; RNG manipulation (avoid songbird).
; TODO use Shift or other keys for RNG manipulation.
;; Enter the schedule of commands.
;; TODO joining with "." can save time and alter RNG.
(enter-commands
[
;; Climb the tree, get egg, and climb down again.
"n"
"n"
"u"
"get egg"
"d"
;; Enter the house.
"s"
"e"
"open"
;; ...
])
C83B:E6 4E 57 GETKEY INC RNDL ;BUMP RANDOM SEED
C83D:D0 02 C841 58 BNE GETK2
C83F:E6 4F 59 INC RNDH
C841:AD 00 C0 60 GETK2 LDA KBD ;KEYPRESS?
C844:10 F4 C83B 61 BPL GETKEY ;=>NOPE
C846:8D 10 C0 62 STA KBDSTRB ;CLEAR STROBE
C849:60 63 RTS
>PUT SOLID
WHAT DO YOU WANT TO PUT THE SOLID IN?
>CASE
DONE.
RNG. Speaking of RNG, the good and bad news is that the RNG in the Apple II version is very sensitive, changing with granularity smaller than a frame. I suspect (but have not confirmed) the Apple II port of Zork uses the built-in KEYIN random number generator, which simply rapidly increments a 16-bit number whenever waiting for keyboard input. This is good in the sense that, in principle, you can probably get any RNG output you need with less than a frame of waiting. It's bad in that it's hostile to console verification, and the Virtu core doesn't provide easy access to sub-frame inputs, as far as I know. In this run, I've done RNG manipulation by manually inserting frame delays. But I also experimented with toggling the Shift key while entering commands, and that alone seems to change the CPU cycles enough to affect RNG. I think it should be possible to eventually do such RNG manipulation automatically, using the script, but it will require more work to understand the game's memory layout, in order to read the results of commands.
ADC RNUM1 ;FUTZ WITH RANDOM
STA RNUM1
EOR RNUM2
STA RNUM2
Connecting commands with dots. It's possible to enter multiple commands at once, separated by periods. This capability is given in the manual. (c-square, your N,N,U,GET EGG,D in Post #476712 would have worked if you used periods instead of commas.) It was the main trick used to speed up the "fastest eaten by a grue" TAS, where it enabled ending input early. I didn't use this feature in this run, but I did a quick test, and to my dismay it appears that entering multiple commands on one line is slightly faster. N.N.U.GET EGG.D was 1690 frames in my test, compared to 1709 frames with the commands on separate lines. I say "to my dismay" because this would be a pretty extreme speed/entertainment tradeoff, a small gain in speed for a large decrease in entertainment. It's nicer to watch a run where the results of commands are close to the commands that caused them, not separated from them by pages of scrolling. I'm tempted not to make use of this trick, except perhaps when traversing long distances, such as through the mazes.
The Troll Room There is a bloody axe here. >e.e.e.echo.get bar East-West Passage Round Room Loud Room On the ground is a large platinum bar. The rest of your commands have been lost in the noise. >
Loud Room On the ground is a large platinum bar. >echo.e The acoustics of the room change subtly. Loud Room On the ground is a large platinum bar. >
I hope to automate this style of RNG manipulation to enable flexible experimentation with routing. As things stand now, if you wanted to try s.e instead of n.e to get behind the house at the beginning of the run, for example, it would desync all later random events. Automated RNG manipulation might also make it possible to play (what is effectively) the same run in either 40-column more or 80-column mode, or in either brief more or verbose mode. That would not normally be possible, because the timing, and hence the RNG, in the various modes would be different. But with a Lua script automatically adjusting the letter case of commands to make sure random rolls always come out the right way, it may be possible for the same route to work in either mode. One movie might have get eGg where the other has get EGg, but they would be effectively the same. Automated RNG manipulation may also make the run robust to timing changes in a future version of the emulator.
| Columns | Brevity | Frames | Time |
|---|---|---|---|
| 40 | superbrief | 18775 | 5:12.92 |
| 80 | superbrief | 19827 | 5:30.45 |
| 40 | brief | 23433 | 6:30.55 |
| 80 | brief | 25139 | 6:58.98 |
| Columns | Brevity | Command |
|---|---|---|
| 40 | superbrief | N;n;hit iT |
| 80 | superbrief | n;n;Hit it |
| 40 | brief | n;n;hit It |
| 80 | brief | n;n;hIT IT |
(enter-commands
[
; ...
;; Get the painting and go back to the cellar.
"s"
"e"
"get"
"w"
"n"
;; Defeat the troll. The troll has a <PROB 33> chance of attacking as
;; soon as we enter the room, before we get a chance to act.
[{:must-not [(make-check-exec-zaddr VILLAIN-BLOW-ZADDR)]}
[
"n"
]]
;; Require a one-hit kill with the shortest remark
;; "The troll takes a fatal blow and slumps to the floor dead."
;; https://github.com/historicalsource/zork1/blob/34cc828c4f/1actions.zil#L3574
[{:must [(make-hero-blow-res-remark KILLED 3)]}
[
"hit it"
]]
; ...
])| Change | Time difference | Comment |
|---|---|---|
| Baseline (Post #538557) | 25139 frames | |
| Change ulysse to odysse | −34 frames | ? |
| Combine two-part commands (e.g. put solid;case → put solid in case) | −1479 frames | |
| Use more conventional words (peal→ring, heap→coal) | +3 frames | ? |
| Stack directional commands (w;s;e;u→w.s.e.u) | −781 frames | |
| temple rather than pray after getting coffin | +152 frames | ??? |
pray frames | pray command | temple frames | temple command | Difference |
|---|---|---|---|---|
4334 | open it | 4334 | open it | 0 |
4511 | u.s | 4511 | u | 0 |
4623 | pray | 4547 | tEmPLE | −76 |
4721 | e.s.e.w.w | 4656 | d.E.e | −65 |
4940 | put solid in case | 4814 | put solid in case | −126 |
5146 | open trap | 4983 | open trap | −163 |
Two subgraphs. The left is a line graph with the title "Frames to reach each input line". The x-axis is "line" and the y-axis is "frames". There are two series: PRAY and TEMPLE. The two series are identical until about line 250/frame 5000, then TEMPLE starts to have slightly fewer frames per line. At about line 800/frame 15000, PRAY moves ahead and finishes at about line 1600 about 150 frames faster. The subgraph on the right is titled "Swaps". Its y-axis is "frame" and is aligned with the left subgraph. Two columns of a few hundred horizontal lines, colored to match the PRAY and TEMPLE lines in the other graph, show at what frames swaps occurred. They are identical up to about frame 5000, then they diverge.
What's going on? I thought about it a lot. My best guess is that is has to do with the virtual memory system of the Z-machine. The game's story file is over 80 KB large, but the Apple II has only 64 KB of memory (and not all of that can be freely used). So what the game does is swap information from the disk into memory on demand. A page table keeps track of what pages in memory correspond to what pages on disk. Once the page table is full, every page that is swapped in from disk necessarily evicts a page that already existed; if that other page is needed again later, it will have to be swapped back in.
I suspect that the pray→temple route change, even though it uses fewer and faster commands, perturbs the contents of the page table in such a way that eventually requires doing more swaps and spending more time waiting for the disk. The right-hand side of the graph above shows the frames at which swaps occur in the two routes. They are identical up to the route change; then they diverge. There are some similar patterns, but one is not simply the shift of the other. In total, the pray route uses 655 swaps and the temple route 670.
This kind of thing is hard to optimize, when a small change can have far-reaching and unpredictable effects. It does suggest a heuristic, which is to try to minimize the ranges of addresses that are accessed. I haven't checked, but that may be what's going on with the ulysse→odysse change. In the source code, ODYSSEUS is the main syntax element, while ULYSSES is marked as a synonym. It may be that these two words are stored in different tables in memory, and that odysse requires only one memory access while ulysse requires two. That's just a guess, I haven't checked. I plan to try switching some commands to use the main word rather than synonyms, even when the synonym is shorter.
It may explain why peal→ring had heap→coal an effect. In this case, though, RING and COAL are the main syntax elements. Maybe the lists of synonyms is near a page boundary, or something. I haven't checked.
Differences in page tables is also the kind of thing where changes elsewhere in the route may end up making the temple variant faster after all.