Prince of Persia Source Code

My Apple II-unaware friend Jamie walked into my office this morning, surveyed the detritus of yesterday’s marathon source-code extraction, and asked “Good Lord, what happened here?!”

Tony and me at the moment of truth

I explained that the original Prince of Persia source code had just turned up after being lost for 22 years, and that two stalwart companions and I had dedicated most of the previous day and night to extracting it and posting it on github.

Jamie — who knows the term “source code” primarily as the title of the movie Jake Gyllenhaal did after Prince of Persia — digested my explanation; then, looking as confused as before, asked “Why?!?”

It was such a simple question, it stumped me for a moment. Why would I spend a whole day trying to recover data from some ancient floppy disks?

I said: “Because if we didn’t, it might have disappeared forever.”

Why source code?

POP source code recovered after 22 years

Non-programming analogy: Video game source code is a bit like the sheet music to a piano sonata that’s already been performed and recorded. One might reasonably ask: If you have the recording, what do you need the sheet music for?

You don’t, if all you want is to listen and enjoy the music. But to a pianist performing the piece, or a composer who wants to study it or arrange it for different instruments, the original score is valuable.

It’s possible, up to a point, to reverse-engineer new source code from a published video game, much as a capable musician can transcribe a musical score from listening to a performance. But in both cases, there’s no substitute for the original document as a direct line to the creator’s intentions and work process. As such, it has both practical and historical value, to the small subset of the game-playing/music-listening community that cares.

This is why I was so sorry to have lost the Prince of Persia source code, and happy to find it again.

Lost and found (Geek quotient = 9)

If you’ve read my 1980s game dev journals, you know that by the time Prince of Persia shipped in 1989, I was burned out on coding and seriously eager for the next chapter of my life to start. So I did what most programmers would do: I backed up my Apple II source code onto 3.5″ floppies, stuck it in a box, and promptly forgot about it.

Thirteen years later, when I looked for that box of source code again, I couldn’t find it. I was in Montreal with an amazing team making Prince of Persia: The Sands of Time. Lead programmers Dominic Couture and Claude Langlais had volunteered to port the original POP to the PlayStation 2, and slip it into our new game as an easter egg. (This was their idea of a fun respite from crunch time.) All they needed was the source code. But as much as we searched — from my garage to Broderbund’s archives to Doug Carlston’s basement — it was nowhere to be found.

Finally we tracked down Scott Shumway, who’d done the 1992 Mac port of POP. He didn’t have the Apple II source code either, but he did have the Mac source code. Dom and Claude made short work of porting it to the PS2, and Sands of Time got its easter egg. Everyone was happy.

On my return to LA, I dug deeper, and turned up a whole shoebox full of Apple II floppies, some dating back to high school. The source code to all my early games was in there: Deathbounce, Karateka. But no POP.

I didn’t need the source code for anything; and it wasn’t as if POP had been lost to history — vintage Apple II POP copies (and their disk images) were widely available — but still, it bothered me to think that something I’d spent years working on was just gone. I felt dumb for not having kept a copy.

This was eight years ago. I gave up the search and forgot about it.

Until two weeks ago, when my Dad shipped me a carton of my stuff he’d found cleaning out the closets of his New York apartment. Inside was the source code archive I’d mislaid in 1990.

Paper is forever

Here’s the thing about digital backups and magnetic storage media: They don’t last very long.

Try popping your old 1980s VHS and Hi-8 home movies into a player (if you can find one). Odds are at least some of them will be visibly degraded or downwright unplayable. Digital photos I burned onto DVD or backed up onto Zip disks or external hard drives just ten years ago are hit and miss — assuming I still have the hardware to read them.

Whereas my parents’ Super 8 home movies from the 1960s, and my grandparents’ photos from the 1930s, are still completely usable and will probably remain so fifty years from now.

Pretty much anything on paper or film, if you pop it in a cardboard box and forget about for a few decades, the people of the future will still be able to figure out what it is, or was. Not so with digital media. Operating systems and data formats change every few years, along with the size and shape of the thingy and the thing you need to plug it into. Skip a few updates in a row, and you’re quickly in the territory where special equipment and expertise are needed to recover your data. Add to that the fact that magnetic media degrade with time, a single hard knock or scratch can render a hard drive or floppy disk unreadable, and suddenly the analog media of the past start to look remarkably durable.

This is why, when I posted about finding the POP source code, digital archivist Jason Scott, Apple II collector Tony Diaz, Derek Moore, and the technical teams behind the DiscFerret and Kryoflux disk readers volunteered their time and effort to give us the best possible shot at a successful extraction.

Let me begin to count the ways I’ve been lucky with this: The box was found. The disks were intact. Prince of Persia and I happened to have a high enough public profile that people of Jason and Tony’s caliber (and dozens of others who contributed their expertise via IRC, skype and twitter from around the world) cared.

In the bigger picture, our timing was lucky. The 1980s and the Apple II are long enough ago to be of historical interest, yet recent enough that the people who put the data on the disks are still with us, and young enough to kind of remember how we did it. Roland Gustafsson, author of the special 18-sector RWTS routines that had made our disks super-efficient in 1988 (and unreadable to anyone but us), was able to get on IRC in 2012 and explain what he’d done to Discferret kids who weren’t born then.

For all these lucky reasons, our archaeological expedition was crowned with success.

From a preservationist point of view, the POP source code slipped through a window that is rapidly closing. Anyone who turns up a 1980s disk archive 20 or 30 years from now may be out of luck. Even if it’s something valuable that the world really cares about and is willing to invest time and money into extracting, it will probably be too late.

This is why it’s awesome that there are people out there working on digital preservation. Because now is the time.

Back up your backups

Jason suggests the following rule of thumb: If you have data you want to keep for posterity, follow the Russian doll approach. Back up your old 20GB hard drives into a folder on your new 200GB hard drive. Next year, back up your 200GB hard drive into a folder on your new 1TB hard drive. And so on into the future.

As for me, the past 48 hours have been a fun walk down memory lane. And have given me a renewed appreciation for paper, celluloid, and stone tablets.

(Postscript: For 6502 assembly-language aficionados, the Prince of Persia source code is now up on github, along with a README file that answers some frequently asked questions. I’ve been amazed and moved by the outpouring of interest in the #popsource saga — it literally crashed this website for several hours today.)

Now, I really need to get back to my day job of making up new stuff. I can only hope to have the same lucky, glorious headache of trying to recover some of it 20 years from now.

Further reading:

“Making of Prince of Persia” game development journal

25-year capsule history of Prince of Persia

POP source code on github

Código Fuente de Prince of Persia – ¡Posteado! (Spanish translation of this post)

Posted on Apr 17, 2012 in Blog, Featured, Games, Making Games, Old School, Prince of Persia | 48 comments

Raiders of the Lost Archives

Two weeks ago, my Dad shipped me a box that, to my joy, contained the original Apple II Prince of Persia source code archive I’d stowed away 20 years ago and had given up for lost.

Despite my eagerness to see what’s on those disks, I’ve yet to pop them in a drive. As readers of this site have cautioned me, digital media degrade with age; if the disks are in a fragile state, normal handling could damage them further and even render them unreadable.

In today’s guest post, digital archivist Jason Scott explains why reading 20-year-old floppy disks is trickier than it sounds — and why he’s volunteered to fly from NY to LA on Monday with special equipment to tackle the job himself.

Monday will be an exciting day. Much like opening a long-sealed sarcophagus, I truly have no idea whether we’ll find what we’re hoping for, or just data dust. For anyone who wants to share the suspense, we’ll be live-tweeting our progress. Hashtag: #popsource. (I wanted to use #sourcecode, but it was taken!)

Meanwhile, here’s Jason’s story, offering a glimpse behind the scenes of a profession whose existence I couldn’t have foreseen or imagined when I was making Prince of Persia in the 1980s: Digital archeologist.

I first heard about Prince of Persia in a somewhat strange fashion; a high school friend said that David’s older brother was working on a new game to follow up his big hit Karateka. I asked what it was about, and he said it was something about Persian princes and acrobatics. I left it at that, but I knew it’d be great, if Karateka was any indication.

I went to Horace Greeley High School after Jordan, and knew his brother, David, who graduated the same year as me. David was the motion model for Prince of Persia. Jordan was this talented figure somewhere out in the fog of the real world, who was making actual, sold-everywhere games with a company I really liked and respected (Broderbund), and was basically living the dream I hoped to live one day: game developer.

(My own dream was fulfilled — I did work for a short time at Psygnosis, makers of Wipeout, as a tech support phone monkey, and another year stint at a startup game studio, before moving on to other places in the computer world.)

It wasn’t until a couple years ago that I moved away from jobs like system administration and backup-watcher into the world of computer history and documentary filmmaking, where I am now. As one of the Adjunct archivists of the Internet Archive, I seek out new collections of data and help preserve current ones — anything from digitized books and audio to long-forgotten shareware CD-ROMs and obscure information files uploaded years ago. It’s a great time, and most importantly, it affords me the flexibility to travel when I’m needed somewhere.

So this was why, when Jordan announced he’d gotten back the Prince of Persia disks he had in his own collection, a lot of friends of mine started linking me to the article and saying “Well?” It was a perfect fit. I had seen Jordan for a few moments after his recent appearance at GDC, so it made sense to have us talk about my coming in to oversee the retrieval of data from the disks. What a nice journey — from hearing the game was being worked on in my youth to helping make sure Jordan’s work lasts for future generations!

Pulling data off dead media in the present day is both easier than it ever has been, and as frustrating as ever. Continue Reading

Posted on Apr 13, 2012 in Blog, Games, Guest Post, Karateka, Old School, Prince of Persia | 20 comments

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Deathbounce Kickstarter: Fully Funded!

In my PAX keynote yesterday, I mentioned that although Karateka is the game that launched my career, I actually had just as high hopes for the Apple II game I made right before it, as a 17-year-old freshman in college: Deathbounce, which I submitted to Broderbund Software founder Doug Carlston but he declined to publish.

A clamor immediately arose in the audience, offering to support a Kickstarter campaign for an iOS/Android version of Deathbounce.

I tried to discourage this, pointing out that Doug’s judgment that Deathbounce was unlikely to set the gaming world on fire was well founded even in 1982. Nevertheless, ever since yesterday, people have been coming up to me at PAX and trying to give me money.

It turns out I actually have a disk image of Deathbounce on my MacBook Air. Continue Reading

Posted on Apr 7, 2012 in Blog, Games, Karateka, Making Games, Old School | 15 comments

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Web Site Admin: Passing the Torch

David Anaxagoras, who’s ably assisted me behind the scenes these past three years, is stepping down as’s website administrator/consultant. In today’s guest post, David says goodbye, and readies the torch for his successor.

If after reading David’s job description and requirements below, you think it might be up your alley, please write to us at

David — Many thanks for your kind words and your diligent work. I know many readers will join me in wishing you best of luck in your adventures still to come.

I’d like to take a moment to say goodbye and introduce myself. You might know me as Jordan’s web site administrator, but it’s more likely you don’t know me at all. I keep a low profile. I move, ninja-like, through the mechnerspace, nipping and tucking bits of code, mercilessly slaying spammers, conjuring solutions from PHP and destroying them when they no longer suit our needs.

For three years I have done this, and now I am about to take my leave. Continue Reading

Posted on Apr 2, 2012 in Blog, Guest Post | 5 comments

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Prince of Persia Source Code — Found!

(Warning: Geek Quotient of today’s post = 11)

My Dad (yep, the same guy who composed the music for the original Karateka and Prince of Persia) called from New York to tell me he was doing some spring cleaning and had shipped me a carton of old games and other stuff of mine he’d found in the back of a closet.

The carton arrived yesterday. My jaw dropped when I saw what was inside.

No, I don’t mean the stacks of Spanish Drosoft versions of POP and Karateka (though those are cool too, especially if you have an Amstrad computer with a cassette player). I mean those three little plastic 3.5″ disk boxes nestled among them… which appear to contain the ORIGINAL APPLE II SOURCE CODE OF PRINCE OF PERSIA that I’ve been searching for, off and on, for the past ten years, pestering everyone from Doug Carlston to Danny Gorlin and everyone who ever worked at Broderbund, and finally gave up hope of ever finding.

I KNEW it wasn’t like me to throw stuff out!

So, for all fifteen of you 6502 assembly-language coders out there who might care… including the hardy soul who ported POP to the Commodore 64 from an Apple II memory dump… I will now begin working with a digital-archeology-minded friend to attempt to figure out how to transfer 3.5″ Apple ProDOS disks onto a MacBook Air and into some kind of 21st-century-readable format. (Yuri Lowenthal, you can guess who I’m talking about.)

This is a crazy busy time (in a good way) with too many projects, so it might take a little while. I’ll document our progress via the twitter and facebook feeds, and I promise, as soon as we can extract something usable, I’ll post it here.

Posted on Mar 29, 2012 in Blog, Games, Making Games, Old School, Prince of Persia | 116 comments

Announcing Last Express for iOS

Update: The Last Express will be released for iOS on September 27, 2012.

I’ve been biting my virtual tongue for the past few months in my eagerness to respond to the many fans of The Last Express who’ve suggested how beautifully this 1997 adventure game could work as an iPad/iPhone app.

Ilya, Veronika, Jan, Jáchym, Sebastian, Felipe, Robert, Will, Stefano, Chiara, Felix, Alexander, Arnim, Jennifer, Lydia, Lauren, Ravi: You’re absolutely right.

It’s with enormous pleasure that I can finally share this good news: A young French company, DotEmu (who celebrated their fifth anniversary in Paris last night — making them ten years younger than the game) is developing a full iOS version of Last Express, to be released later this year.

Details to follow — but be assured, this will be the complete, original PC game, a deep and immersive real-time interactive narrative offering 20+ hours of game play, with a few additional enhancements to make it more iOS-friendly.

For those who are new to The Last Express, you can read about the original game here. Watch this space, and the official Last Express facebook page, for updates.

My thanks to DotEmu, the original Smoking Car team, and all the Last Express fans who’ve encouraged us to refill the coal tender and stoke the furnace so that this train can leave the station once again, fifteen years later.

I can’t wait!

Posted on Mar 16, 2012 in Blog, Games, Last Express, Old School | 54 comments