Wednesday, 9 December 2015

The Daily Life of a Game Programmer

This is the concluding part of my 1988 interview with Infocom’s Dave Lebling (See also Part 1 and Part 2).

I read a little while ago that you get problems from Christian fundamentalists who object to your stories?

It’s really a pretty minor problem. There is a certain antipathy on the part of a certain class of religious fundamentalists to any reference to magic. Most of our fantasy games have magic in them. I think the thing that caused the greatest number of complaints was when we ran an ad’ for Spellbreaker which showed a picture of a wizard. We ran it in Boy’s Life magazine which is the magazine of the Boy Scouts. Boy Scouting in America is very strong amongst the same class of people who are likely to be religious fundamentalists. So parents saw this ad’ and got annoyed. I must say we got more letters about that than we ever got about sex. We did get a few complaints about The Leather Goddesses of Phobos, but not as many as we’d feared. I think Leather Goddesses was sufficiently obviously packaged that most people who bought it were not surprised. It didn’t sneak up on them.

You got some other complaints too, didn’t you - about your newsletter, The New Zork Times. I gather you were obliged to change its name.

It depends on what you mean by ‘obliged’. We periodically got letters from lawyers of The New York Times complaining about the title of our newsletter.

And these complaints were in all seriousness?

Oh, they were quite serious. But we ignored them. Finally, about the same time we were merging with Activision, and their lawyers and our lawyers were poring over everything that might be a potential drawback or holdup to the merger, we got a particularly nasty complaint. Instead of saying ‘We object to your use of our trademark’, they said ‘Stop using our trademark or we’ll see you in court’. ' 

I find it almost incomprehensible that they could really be serious. What were they afraid of — that people were mistakenly going out to buy New Zork Times instead of the New York Times?

I don’t know. My understanding from talking to the legal people at Activision is that the real problem is that if you own a trade mark you are obliged to defend that trademark against infringement, otherwise your trademark can become a generic term as happened with Kleenex.

Maybe the newspaper’s lawyers were just in a bad mood because they hadn’t managed to solve the latest Infocom game?

Hmm, now that may be a possibility...

This interview originally appeared in Computer Shopper magazine #7 (September 1988).

How about you? Do you get around to playing the games written by all the other Infocom programmers?

Not as much as I’d like. But I try to play as many as I can.

Does the experience of writing so many games help you solve other people’s games?

No, it really doesn’t actually. Because different authors have a different style. The fact that I’ve written so many games doesn’t help when I play Steve Meretzky’s games because his style is so different. And Brian Moriarty’s is even more different. On the other hand, we play them on a version of our interpreter that allows you to escape into debugging, so I can always cheat.

Have you got a favourite game?

My favourite game of the ones I have written is Enchanter. Then after that I guess Spellbreaker and The Lurking Horror. Though maybe Zork II. Zork II was really our first game that really had anything remotely resembling a story in it. It’s hard to say. Of everyone else’s games I’ve always had a fondness for Planetfall. I like all my games but I always see the flaws in them.

How similar is the Zork Trilogy to the original Zork?

It’s quite similar in that all the puzzles in the original Zork are also in the Trilogy with the exception of two. What’s different is that the original Zork had one fairly compact, connected geography. In the Trilogy what happened was that I went in and chopped out the middle of that geography and it became Zork I. Then I made a new middle and added some of the periphery of the mainframe game to make Zork II. And then the remaining puzzles became Zork III. All the puzzles are there and the vast majority of the rooms too, but they’ve all been rearranged.

I have to tell you that one of the things that had me puzzled about Zork II was all the references to baseball which I didn’t understand at all.

Yes, since we’ve gotten more contacts from fans beyond the United States — Germany, Britain, Australia and so forth — it becomes more and more clear that references to things like baseball are not universally appreciated. It didn’t even occur to us that the games would have been distributed as widely as they are.

Which do you think is the most difficult Infocom game?

Spellbreaker. It was designed and written as a gift to rabid fans. It’s the third game in a trilogy and it’s intentionally more difficult because I was getting sick and tired of people writing to me saying the games were too easy. I thought, right, you’ve asked for it. Some of the easiest puzzles for some people can be insoluble and vice versa.

Do you get feedback from other people giving you alternative solutions to puzzles you never thought of?

Sometimes. Occasionally, people just alert us to things we hadn’t thought about. Like, it used to be that the inflatable boat in Zork I could be used to carry every object in the game once you’d deflated it. But the classic case of getting a new solution to a puzzle was when we were writing mainframe Zork. We had just implemented the clockwork canary inside the jewel-encrusted egg. Someone was playing the game and said ‘I’m really having trouble with this. And it’s frustrating because I know exactly what you’re meant to do once you get the canary.’ We said ‘Oh really?’ — because we had no idea what you were meant to do. He said, ‘You’re supposed to take it up to the forest and wind it to attract the bird.’ We said ‘Oh, of course. yes, that’s right... er, but be sure you don’t play any more of the game until tomorrow!’

Do you ever go back and alter games once they’ve been released?

When we make new disk masters we often release versions with bugs fixed. The only case I can think of where we’ve actually altered a puzzle was when we changed the Loud Room in Zork I. It was a more difficult puzzle on the mainframe Zork but it was also more illogical. We just got so annoyed with it. By today’s standards that puzzle was terrible. But when we wrote it we thought it was pretty good stuff.

Do you see a day when you’ll say ‘That’s it. I’m never doing another game in my life?’

I always say that about two weeks before my game ships. I suspect at some point I might conceivably run out of ideas.

Is it still fun or is it just a job?

Oh it’s still a lot of fun. If it wasn’t fun it wouldn’t be worth doing.

Infocom games can be downloaded, free, from several locations on the Internet such as and – there are even versions for iOS: In some cases, you may need to add a DOS emulator such as DOSBox to run these games.

Tuesday, 8 December 2015

Back To The Future (of Computer Games)

In my 1988 interview Infocom’s Dave Lebling tries to guess where computer games are headed. But was he right…?

Once upon a time Infocom was just about the most famous games company on the planet. They made ‘interactive fiction’ - adventure games in which the game player moved around a huge world of linked locations (‘rooms’) breaking into buildings, taking treasures and killing monsters. In September 1988 I interviewed the co-founder of Infocom, Dave Lebling, for ‘Computer Shopper’ magazine. We talked about the history and the future of computer games. We talked about the massive resources needed to run good games (a huge 256K of memory), the languages used to program games (a variant of LISP) and pondered that most difficult of questions: would computer games one day use lots of graphics or would players be happy to carry on using text-based interaction to communicate with games with English-language commands?

Well, we know the answer to that! These days the sophisticated, fast-animation of the modern generation of games has largely driven the development of ever more powerful graphics hardware. Whereas Dave Lebling was worried about the number of kilobytes required by a game, these days we discuss game requirements in gigabytes! It’s a different world. And yet the foundation for modern games was laid by people such as Lebling. Even modern games often use the same sort of plots (exploring, gathering treasures, killing enemies) as the old Infocom text adventures. But, in spite of their slick graphics, not all of them have half the wit and imagination of those early games such as Zork.

If you are interested in games, game programming or simply the massive development in the processing power of desktop computers over the past few decades, I hope you enjoy this historic interview with one of computer gaming’s great innovators.

See also the introduction to this interview:  From Zork To Assassin’s Creed – three decades of computer gaming.

Just a few of the many games created by Infocom

When you first wrote the mainframe version of Zork did it occur to you that you might be able to make some money out of it?

Oh no. We had written Zork kind of as a lark back in 1976/7. There was quite a history of that sort of thing at MIT — lots of people did that kind of ‘midnight programming projects’ — you know, the kind of thing you just didn’t do during normal working hours. There were a lot of what would now be called video games and a lot of trivia games — lots of things to keep you entertained. And Zork was just one more...

So you are saying that you and Marc Blank just managed to jot it off in your free time when you were both still students?

No, not exactly. There were four of us involved. Some of us were students. Some of us were not. I was a staff member, a researcher. Marc Blank was a student, Tim Anderson was a graduate student and Bruce Daniels was a graduate student — they were the other three authors of the mainframe Zork.

What language was Zork written in originally?

It was written in a language called Muddle (MDL - an ‘AI’ language developed at MIT). It’s like LISP - it’s a recursive structure-oriented, user extensible language. People who know LISP can look at Muddle and sort of figure out what they’re doing.

If it’s so similar to LISP, why didn’t you just use LISP?

Because Muddle was the language that our research group used. When we moved to Infocom we wrote another language especially for implementing Zork - that was ZIL — very much like Muddle itself but adapted specially to deal with adventure games.

What’s the difference between ZIL and a more standard version of LISP such as Common LISP?

The most obvious difference is that instead of having parentheses it has angle brackets. That’s the first thing that would strike a LISP user as being strange. Other than that, ZIL has in it operations for doing the kind of things that are useful in Adventure games - moving one object from one place to another and very quickly checking to see if an object has a particular property. But there’s nothing in it that couldn’t easily be implemented in a good LISP system.

How has ZIL developed over the years? You’ve had several different versions as I understand it.

Oh, absolutely. In the first version the actual game size was 128K and there was a maximum of 256 objects - and that includes rooms as well as treasures and so on. In ZIL the rooms and the objects are represented in the same way. But at present the maximum game size is 256K and there is, in effect no limit to the number of rooms and objects. There are other changes too. Up till now our development system has been run on a DEC System 20 but now we’re moving it onto a Mac II. The Dec 20, although we love it dearly and wish it would stay around forever, is unfortunately obsolete. It’s a huge, expensive mainframe computer. It costs a lot to maintain. It even has to have its own air conditioner. It’s really quite a drain on resources and we think the Mac should be a lot more manageable.

When the games are released, what form are they in? You seem to have some kind of basic program which reads in the data. Is it interpreted in some way when we play them?

Yes, it is an interpreter. ZIL itself is a virtual machine. That means it is a computer program which simulates the behaviour of a particular non-existent computer. It’s a bit like the kind of thing IBM do. They are famous for simulating earlier models of their computers. And the way you do that is to write a piece of software that acts like a CPU. Ours isn’t emulating an existing machine, it’s simulating a machine that doesn’t exist in hardware. But theoretically it could. Another similar idea is languages like Pascal which are often compiled into what’s called a p-code. We call our thing the zee-system. It was done in this way to make it easy to convert from one computer to another. Now as we move into the uncharted waters of sound and colour, it’s becoming more and more difficult to maintain that portability.

Sound and colour! I thought they were an anathema to you. You’re not saying that Infocom is finally going to break with tradition and go into the sordid world of graphic adventures, are you?

Yes. We’re thinking of that.

After all those years when you’ve said you’d never have anything to do with graphics! What’s brought about this change of mind?

When people ask me about graphics, I have never said we will never put graphics in our games. What I have said is that we will never put graphics in our games until a) they enhance the game and b) they do not detract from the amount of game available to the player. I mean, graphics eat up disk space and memory. If you put in 20 pictures, it would be unconscionable to reduce the game to half its size.

So are you thinking of graphics you can look at every once in a while rather than fully animated graphics?

That is close to what we are thinking of. 

In other words, just like Magnetic Scrolls adventures.

I haven’t the slightest idea what you’re talking about! Oh well, OK, to be honest, we are very closely affiliated with Magnetic Scrolls, we like them a lot and I think they like us. I’ve heard that they have even put in quite a few references to us in their games.

Is this an admission that you consider Magnetic Scrolls’ games like The Pawn and Guild Of Thieves to be your main competition?

I would not go further than to say that we consider ourselves to be friendly rivals.

Magnetic Scrolls was a British company that broke with convention by adding graphics (static  images) to their adventure games and also improved the ‘parser’ to interpret more complex English-language commands.

One of the things Magnetic Scrolls pride themselves on is their parser. The ‘in thing’ seems to be to allow users to type in an ever more varied range of grammatical constructions. But I wonder how many people ever get around to exploring the possible things you can say to an Infocom or a Magnetic Scrolls game? Most people end up just saying ‘Read scroll’ or ‘Kill troll’, don ’t they? So is it really worth developing parsers beyond a certain point?

I think it is. It’s a controversial opinion, but I think the advantage of a better parser is that the player can say more things to the game and be understood. The disadvantage of a better parser is that the player can say many more things that will be superficially understood but not actually understood. You can’t just blithely go off and say: Oh, sure, I’m going to have a parser with ellipses and questions and statements and so forth and so on. You have to do it fairly carefully. Magnetic Scrolls have done a fairly good job of extending the basic three-word parser and adding on a few more bells and whistles.

And you are going to respond to that challenge, I presume.

We’re certainly hoping to carry on improving our parser. Over the last few months we rewrote the parser from scratch. The games that we’ll be producing later this year will have that new parser. It will have all the capabilities of the old one plus a few new ones.

Good parsers obviously need good programmers. But I gather that some of the people who write Infocom adventures are not programmers at all. Does that mean that just anybody can be given your system and a manual, put in front of a computer and start writing an adventure?

Not exactly. I think a better way of saying it is that some of our writers are not professional programmers. You could not take an author off the street and just let them get on with it. You can take someone who’s technically sophisticated, like, say, Douglas Adams, with Hitchhikers. He can comprehend what’s going on, though in actuality Steve Meretzky did all the programming. Many of our writers have not previously been professional programmers so it’s not an inherently difficult system to learn. Part of the reason for moving onto the Mac is to make it more usable to non-programmers.

Where do you find new games writers?

All kinds of places. Usually they approach us. The vast majority of writers have come from promotions in-house - people we knew already, who we’ve tried out on small projects. That’s basically how Steve Meretzky came in — he was a tester. Brian Moriarty was in our Systems Group - the expert on 6502 chips. Amy Briggs was another one who came in from testing. And occasionally we’ve hired people from outside.

What kind of organisation is there in Infocom? You’ve talked about testers and so on. Is there a kind of elite of games writers and millions of people just testing for bugs?

There’s what’s called the Software Development Group. That’s divided into three parts. One part is familiarly known as the Imps, that's the games writers, the second is the Testers. Then the third group is called the Systems Group. These are the people who maintain ZIL and various computers. I have to say that the Imps are a sort of elite.

What's an average day for an Infocom programmer? Do you just come in as though it was an ordinary job and get on with your work? Or are there times when your mind is just a total blank and you can’t produce anything?

What it really depends on is what stage you are in writing the games. If you are still in the design process you may well come in and scratch your head a lot. Later, once the game is largely complete, you spend a lot of time reading the scripts of testers playing the games, seeing what they tried and modifying the game appropriately. And just fixing bugs.

What exactly do the testers do? Do they just spot bugs or do they suggest new puzzles?

They do everything from just beating on the program to see if they can break it to making, in effect, literary criticism. Everything from nit-picking about whether a particular word should have a hyphen to a deep analysis of what is going on in a program as regards the story.

Is it a big problem now finding ever-new ideas for games? There are so many Infocom games and you’ve covered so much ground...

Well, I don’t have any difficulty coming up with ideas. If you view the spectrum of what we put out - we have sci-fi, fantasy, mystery and romance - when you do a new thing you aim it at one of those points. You have an audience in mind. You want to satisfy those fans. The avid fans are always calling for more difficult puzzles. They complain if it only took two weeks to finish such and such a game. On the other hand, you don’t want to make them inaccessible to people who haven’t got so much experience at playing games.

The Lurking Horror was one of the games written by Lebling.

When you're stuck for ideas where do you go? Do you go to a library to ransack books, do you play other games or do you just ask one another?

All of those things. For his current game, Steve Meretzky has been collecting books of logic puzzles. In general we all get ideas from books. I have a very large library. Lurking Horror was quite obviously the result of reading too much H.P Lovecraft.

These days you are putting on-screen hints for people who do get stuck. Will these appear in all future releases?

At the moment, that’s our plan. We’ve had mixed reaction to it. Some people love the idea, some people hate it. We may even go so far as to put on-line maps later. That’s still under consideration. We tried out the idea with Beyond Zork. But Beyond Zork shows you a fairly small section of the total map. It would be nice if you could see a bit more of it.

[To be continued...]

Saturday, 5 December 2015

From Zork To Assassin’s Creed – three decades of computer gaming

In 1988 I spoke to one of the great figures in computer gaming about “the future of games”. Dave Lebling was a founder of the Infocom games company, which created games ranging from the famous Zork trilogy to an adaptation of Douglas Adams's The Hitchhiker’s Guide To The Galaxy. Of course, neither of us back then had any real idea of how the games industry would develop over the next 25 or 30 years. Back then I played Zork – a text-only game which ran nicely on my PC with just 512K of memory. Today I am playing the photo-realistic, fast-action Assassin’s Creed Syndicate on a PC whose graphics card alone boasts 6 Gigabytes of memory in addition to the 16 Gigabytes of the PC’s system memory. In 1988, mere megabytes of memory seemed like a futuristic dream. The idea that anyone would ever have gigabytes on their graphics card would have seemed ridiculous.

So what future for gaming did Lebling envisage back then? As you’ll discover when I publish the interview in full, Lebling had only recently begun to take seriously the idea of games with static graphics – and he wasn’t at all sure that animated graphics were the way forward: “We will never put graphics in our games until a) they enhance the game and b) they do not detract from the amount of game available to the player,” he told me,  “I mean, graphics eat up disk space and memory. If you put in 20 pictures, it would be unconscionable to reduce the game to half its size.”

Here is the introduction to my 1988 interview with Lebling. The interview itself will follow shortly.

The Man Behind Zork

Dave Lebling, co-founder of Infocom, the ‘interactive fiction’ specialists, speaks to Huw Collingbourne of Zork and the futures of games

FOR ME one of the best things about Infocom games is that most of them are written primarily for adults. As such they are complicated, difficult and often surprisingly serious in tone (the people at Infocom like to call them ‘interactive fiction’ rather than mere ‘adventure games’).

Anybody who has yet to experience one of them should be warned - unlike some games you may have played, these are not to be treated lightly. They are dangerously addictive and their effects can be highly unsettling. I’ve seen intelligent and level-headed people transformed into gibbering idiots after sleepless nights wandering through the Great Underground Empire or the outer reaches of the Galaxy. Confirmed addicts may experience weeks of gloom and depression because they can’t get over the rainbow or catch a babel fish to stuff into their ears.

Oddly enough, although it is now one of the most successful entertainment software companies in the world, it was only by chance that Infocom did not become a business software company instead. Indeed, it did once launch a database called Cornerstone but, for some reason, people seemed to find this a lot less entertaining than their other products such as The Hitchhiker’s Guide To The Galaxy.

Set up in 1979 by a team of eight programmers, the company initially had no clear idea of the kind of product it should develop. It just happened that some of the Infocom programmers had previously written a text adventure game which was circulating on mainframes in the universities and was already becoming something of a cult. And they wondered whether it was possible actually to sell such a game.

In the event, two programmers, Dave Lebling and Marc Blank, decided to have a go at converting that mainframe adventure to run on the less powerful personal computers which were then starting to be manufactured. That game was Zork. And when I spoke to Dave Lebling recently, I started by asking him about the genesis of that immensely successful adventure.

A short history of text adventures

Interview to follow…