Note: A description of a violent event follows.On December 6th, 1989, I was a third-year student in the Faculty of Applied Science and Engineering at the University of Toronto, enrolled at the downtown campus.I had finished with classes for the day, and was back in my room in the shared apartment where I lived, when my phone rang. It was my eldest sister, who was living in New York at the time. I've only gotten a few phone calls like this in my life: a family member who I know well enough that I can tell, with a single word—even just 'Hello’—that something is very, very wrong.She was calling because of something she had heard, on American news, elided and summarized in the way news items about events outside the US usually are, and she needed to know that I was okay. Over the following days, the full details of what had happened became clear.Late that afternoon, a man had walked into the École Polytechnique, the engineering school of the University of Montreal, carrying a hunting rifle, ammunition, and a knife. He entered a mechanical engineering class of about sixty students, separated out the nine women, and told them, "I am fighting feminism." One of the women, Nathalie Provost, responded, "Look, we are just women studying engineering, not necessarily feminists ready to march on the streets to shout we are against men, just students intent on leading a normal life." She reports that his response was, "You're women, you're going to be engineers. You're all a bunch of feminists. I hate feminists."He then opened fire on the women, killing six of them. Then he went from floor to floor in the building, targeting and shooting women.Fourteen women were killed that day, twelve of them engineering students, one a nursing student, and one a university employee.Here are their names: Anne St-Arneault, Geneviève Bergeron, Hélène Colgan, Nathalie Crotea, Barbara Daigneault, Anne-Marie Edward, Maud Haviernick, Barbara Klueznick, Maryse Laganière, Maryse Leclair, Anne-Marie Lemay, Sonia Pelletier, Michèle Richard, and Annie Turcotte.An additional thirteen people were injured. Nathalie Provost was shot four times, but survived.In the weeks, months, and years that followed, among other responses, Canada implemented stricter gun-control regulations, and began to observe December 6th as a National Day of Remembrance and Action on Violence Against Women. The event remains the worst mass murder in Canadian history.The École Polytechnique shootings are as much a part of the history of women in technology as Ada Lovelace or Grace Hopper. I don’t think I fully realized the impact on my life for a decade or more, through graduate school, through my postdoctoral work. And then one day I realized how much the shootings had shaped who I was, not least that I was on the faculty of an engineering school that has (by institutional commitment) half women students, and that a number of my colleagues and I were deeply engaged in work around gender and engineering education. It was like looking at a string of stones on the surface of the water, and realizing they were part of a giant monster submerged below.I would like nothing better than to believe that the events at the École Polytechnique were an aberration, to subscribe to the narrative of the lone insane gunman. But the reality is that the presence of women in technology, as in many fields thought of as the domain of men (including, as Mary Beard has trenchantly written, the public sphere ), is still considered illegitimate by many. This is expressed in a wide range of ways. At the ‘harmless’ end of the continuum is the common response to women saying they’re in technology: an expression of surprise. Then there is the gamut of inappropriate comments, harassment, exclusion, and implicit biases. At the age of 18, while still an engineering student, I learned what the other end of the continuum was.I would like nothing better than to forget the events at the École Polytechnique, for it to be a distant faded memory from a darker time. But 2014 brought us the toxic efflorescence of harassment and threats that was GamerGate. The anonymous e-mail that prevented Anita Sarkeesian from speaking at Utah State University threatened, in part, that a 'Montreal Massacre style attack [would] be carried out'. And 2014 also brought us the Isla Vista killings: someone who wasn't even born in 1989 went to a sorority house with the deliberate intention of killing women who, like the Montreal engineering students, had something the shooter felt he deserved to have. It wasn't until I consciously registered the parallels that I realized why I had found myself unable to stop crying when I learned about it.There's often a sense that women in the tech world make a big deal out of small events. But the myriad ways in which they are told their presence is illegitimate, that tells them that they don't belong, is a constant pressure pushing them towards leaving technology (and game journalism, and the public sphere). In particular, when women in technology also have public voices, as with Anita Sarkeesian or Brianna Wu or Kathy Sierra, the pressure can be—is often intended to be—crushing.I don’t think being a woman in technology is worth dying for, but I learned early that some men think it’s worth killing for.