For 3 days in 2006, nobody at my high school could turn in homework because of my dumb joke.

In an effort to annoy my friend Brody I had (accidentally!) brought down SWIS - the School Wide Information System - at Northfield Mount Hermon high school.

I’ve mentioned this in passing before, and I think the details are interesting so I thought I’d write it down.

Defining SWIS

Very briefly: SWIS was something between an email system and a forum. You could send mail to people (your friends, your teachers) and create threads, like an email client.

the only good image about SWIS that I could find...

But it also had lots of ‘forums’ - places that we went to find school announcements, discuss classwork and turn in homework, and even argue about politics.

It was great and weird and wonky and a real part of student life. I have to imagine it doesn’t exist anymore.

And I broke it, accidentally, repeatedly, for several days.

Annoying my friend

So three things you have to know here are:

• SWIS had powerful mail rules
• I went to a boarding school and I was around my friends all the time
• I was an annoying 1 highschooler

When you got mail while SWIS was open 2 it made a loud ding. It was loud! My friend Brody always wore headphones during evening study hall, and I noticed that he’d often jump when a message came in.

This was funny to me! Sometimes I’d send him mail to get him to jump.

But I noticed, sometime during my sophomore year, that SWIS had a bunch of programmable mail rules. You could filter mail, sure, but you could also automatically send mail. So I wrote a little rule. It said:

• If I get an email from myself with an empty subject line
• Send an email to Brody
• Send two emails to myself
• Delete the mail from myself

I sent myself an email with an empty subject line. Which sent Brody an email, and sent me 2 emails. Which sent Brody 2 emails and me 4 emails. Which…you get it. Within seconds I was sending Brody (and myself) thousands of emails. My rule automatically deleted the emails on my end, so I was safe. But Brody had no such protection, and he got thousands of emails, which meant thousands of dings.

It startled him! This was funny to 15 year-old me. I was happy.

Ethical hacking

I didn’t leave the rule enabled for long; running it for a few seconds was enough.

And I immediately reported it! I emailed Richard Eisenberg, my high school computer science teacher explaining what I had done. Richard went on to make substantial contributions to Haskell and then briefly overlapped with me at Jane Street before I left to do whatever it is that I do now (this fact is unbelievably cool to me).

Anyway. I hope that Richard was entertained by my mischief. I don’t remember exactly what he said, but I think it was something like “this is funny, nice work, don’t break the server.”

Oops.

Onwards

I enabled my mail rule a few more times to torment Brody. But Brody was smart, and was also a programmer! Pretty quickly he figured out what was going on 3 and started deploying countermeasures.

He set up rules that automatically deleted empty emails from me and spammed me right back. So I set up rules that detected those emails and started changing the patterns that I put in my subject lines.

Pretty soon we were both just automatically deleting any email that the other person sent. This was fine; we saw each other in person all the time.

And that’s what lead to my error. Our countermeasures became so good that I no longer knew when my rule was running, since no emails reached either of our inboxes.

So I accidentally left it on.

The Crash

I woke up the next day and SWIS was down.

This was bad! Like I said, SWIS was a critical part of student life. We couldn’t turn in homework or find announcements.

But I didn’t think much about it. That afternoon it came back up. And immediately crashed again.

This pattern repeated for days - SWIS comes up, SWIS goes down. I think I printed out my essay and turned it in by hand.

At no point did I consider that I might have done something wrong here.

What happened?

Well, I had never turned off my rules. And when SWIS crashed there were still emails in flight between Brody and I.

SWIS was crashing because I had a mail rule that quickly sent millions of emails, overwhelming the system. Those rules didn’t go away after a crash! So the second it came back up it’d get right back to sending my millions of emails, bringing it right back down.

Eventually folks figured out what was going on. I don’t remember the names of the folks in our IT department (sorry! It’s been almost 2 decades!) but I’d imagine that they found some way to observe the crash and trace the emails back to my rule. Maybe they had a way of booting into a “recovery mode” where emails weren’t sent, or maybe they just debugged during the short periods where the system stayed up. But eventually they disabled my rule.

I’ve always enjoyed fire fighting; I hope that the debugging process was fun (I’d imagine it wasn’t. Sorry again).

Aftermath

The IT department found and disabled my rule. But they didn’t really understand what was going on.

They thought that Brody and I were in a fight - we were automatically deleting each others emails! - and that we had inadvertently crashed the server while fighting.

They emailed us and our advisors explaining what we’d done. I’ll never forget one line from the email: they requested that we “sort out our interpersonal issues offline.”

I quickly explained to my advisor - the lovely John Christiansen - the actual story. And he found it hilarious. We were due for yearly T-shirts for our dorm and he put a joke about it on the back of mine 4.

I got in no real trouble, and I stayed away from mail rules for the rest of my time in school.

It’s fun to have fun

I think about this story all the time.

I think there’s a clear line from “abusing mail rules for a joke” to many of the projects on my blog like running flappy bird in finder; it’s fun to look back and see that I was the same person at 15 that I am now.

But I think there’s a broader point here. I got up to a lot of mischief in high school, and plenty of that mischief was met with encouragement (or at least appreciation).

That wasn’t always true; I got in real trouble for some of what I did 5. But I think folks recognizing that what I had done was neat (while perhaps gently nudging me in more suitable directions) was critical to me developing my playful spirit.

I didn’t realize it at the time, but I was extraordinarily lucky back then. As a concrete example, I had a pretty rough time in my late teens, which meant that I never graduated from college and don’t have too much formal computer science training.

But having an extraordinarily talented computer scientist as your high school teacher goes a long way! I’d take “being Richard’s high school student” over a degree any day.

So thanks, Richard and John. I hope today’s kids are as lucky as I was.