!!Con 2017 Notes

Listed in the same order as the program.

Day 1 Keynote

Cyborgs Unite! (Karen Sandler)

• Software Freedom Conservancy: support participation in free software, enforce the GPL
• Karen has a disorder where her heart is too big, so she uses a pacemaker
• The physiologist didn’t know that there was software running on it!
• What does it mean to be a cyborg if the software isn’t free?
  • Normally, people look at you weird when you say that you like free software
  • They start to understand when you mention that you have proprietary software running in your body
  • People without implants are simply “future cyborgs”
• Karen’s getting a defibrillator upgrade soon
  • New ones have radio telemetry. There’s no way to disable it!
  • Compared with last time, people are starting to understand these issues. Doctor’s office no longer confused about software. Went out and asked about security.
• Programmers have the knowledge of the technology that runs our lives, and therefore the ability to educate others about it
  • “What does it run?” Our ability to ask technical questions about these products gives us power.

Session 1

Serious programming with jq?! A practical and purely functional programming language! (Charles Chamberlain)

• Imperative language: do some stuff and then return something
• Pure functional language: just return something
• jq is a language for inspecting and processing JSON data
  • Like awk for JSON?
• To do things in jq, we pipe stuff to other stuff:

  "foo" | length => 25
  { "key": "value" } | myfunction()
  

• jq is purely functional except for the debug function
  • Passes the data straight through (identity function), and prints the data out too

Finding Friends in High Dimensions: Locality-Sensitive Hashing For Fun and Friendliness! (Aaron Levin)

• k-nearest neighbor at Soundcloud: make music into vectors, and recommend new music by finding nearby vectors
• N^2, so it “takes too damn long” :(
• Locality sensitive hashing algorithm assigns points to neighborhoods
  • Randomly choose separating planes, and assign 0 or 1 for each point for each plane, resulting in a bitvector for each point
  • Number of same bits approximates angle between vectors! Angle calculations reduced to bit math.
  • Sort the bitvectors
  • ???
  • O(s * N * log(N))
  • Profit!!

What alien invaders, birds, and computer simulations have in common: flocking!! (Jan Mitsuko Cash)

• In movies, when aliens flock, there’s central control telling everyone where to go. This is a problem for the robustness of alien invasions!
• However, in nature, flocking birds or turtles use distributed control (emergent behavior)
• To write simulation, use an the NetLogo agent-based language
  • You write the code that “runs on” each turtle in the flock
• 3 rules in our flocking simulation
  • Face same direction
  • Stick together: Turn toward the center of your neighbors
  • Personal space: Turn away from anybody in your bubble

I wrote to a dead address in a deleted PDF, and now I know where all the airplanes are (Jason McIntosh)

• How does the FlightRadar24 app know where flights will turn ahead of time?
• Are there public APIs?
  • FAA: no public APIs
  • FlightAware: expensive commercial APIs :(
  • NOAA: API for getting turbulent areas
• Spent a lot of time trying to scrape NOAA images, without using the contact links at the bottom!
  • “Contact form is probably read by some public servant who cares deeply about their work”
• Ran through many PDFs, eventually emailing FAA to ask for ASDI data
  • Response: We retired that years ago! Have you checked data.faa.gov?
• Step out of the ivory tower and ask other people for the resources you need!

Session 2

Requiem for a nemesis! (Nick Sullivan)

• Programmers are like composers. Reverse engineering is like hearing the song and trying to come up with the sheet music again.
• Obfuscators’ job is to make a mess, like turning if statements to for loops that don’t branch
• Enter Requiem, Nick’s nemesis. It’s an automated reverse engineering tool for music-playing software.
• More obfuscation!
  • Add random functions like Newton’s method that don’t do anything
  • Inline everything
  • Encrypting memory with a custom allocator
  • For 5 years…
• Requiem author retired

Glk! A universal user interface! for interactive fiction! (Andrew Plotkin)

• Interactive fiction: old-school text games
• Zork virtual machine specification was created to run the Zork game
• N^2 problem of connecting Zork VM backends with UIs
• Glk interface connects interpreters to interfaces
  • C API, later ported to JavaScript for web and Java for Android

How do Keyboards Work? HIDing, in Plain Sight!! (Scott Vokes)

• Keyboard is a bunch of switches arranged in a grid of read wires
• Firmware scans the grid (key matrix), looks up the layout, and sends data over USB
• USB
  • “It’s called the Universal Serial Bus, so you know it’s going to be a bit complicated”
  • Enumeration: descriptor tree describes which devices are on the bus and how they communicate
  • Human Interface Device (HID): refers to keyboards and mice and stuff. The drivers are built into everything.
  • Debugging USB: there’s a Linux kernel extension that makes USB into a network interface, so you can sniff it with Wireshark!

Making Mushrooms Glow! (Bomani McClendon)

• Bomani worked on an art project of computer-controlled mushroom light
• Software responsible for controlling the lights and making the mushroom open when someone stands near it
• Raspberry Pi embedded in the mushroom is a dumb terminal, with all the business logic on the server
  • Allows coordination between mushrooms
  • He’s a web developer, because the server could be written in Node.js

Session 3

Why So Loud! Geeking Out on Airline Data, Physics and Mapping (Ewan Dennis)

• While moving, Ewan wondered whether certain homes would be too loud
• “I don’t have the background” to do this project, but tried to break it down as a development task anyway
  • FlightAware to get the actual flight tracks of planes
  • How loud is a plane? Looked up “sound pressure level” on Wikipedia!
  • Learned how sound propagates through open air using Wikibooks

Writing NES games! with assembly!! (Christian Joudrey)

• Background: Web developer, mostly works in Ruby
• NES designed so that cartridges can take advantage of new technology introduced in the future
  • No persistent storage: games used passwords that let you skip to the level you were working on before. Zelda added RAM and a battery in the cartridge.
• No APIs to call for anything: to display things, read controllers, etc. just read/write to certain memory-mapped I/O.

The TOP 5 Queer Feminist Cyberpunk Manifestos! (Jean Cochrane)

• #5: A Cyborg Manifesto by Donna Haraway
  • Critiquing 70s mainstream feminism
  • Argued that technology will abolish gender
  • Bad readability, “long and dense like only queer feminists can be”
• #4: some artists(?)
  • “The future is unmanned”
  • Women will take over male-dominated
• #3: 100 Anti-Theses: What Cyberfeminists Are Not
  • A conference
  • Thesis: “Cyberfeminism” doesn’t mean anything except being angry in a 90s way
• #2: The Cybertwee Manifesto
  • More soft and artsy work, while still being aggressive and angry
  • These days, cyberfeminism is more about art than politics
• #1: Xenofeminism: A Politics for Alienation
  • (This was too dense for me to understand)

Corruption in the Data Center! TCP can fail to keep your data safe! (Evan Jones)

• A debugging story
  • The server sent the correct response but the other end received it wrong (the network corrupted the data!)
  • Unplugged racks until the problem went away, but corrupt data was reaching other parts of the system
• How can this happen?
• TCP and Ethernet frames both have checksums
• Ethernet: Switches may need to modify packets, so they remove the CRC, queue the data, and compute a new CRC on sending
  • If the data is corrupted in the queue, switch will compute a checksum over the corrupt data
  • Therefore, Ethernet CRC only protects you from wire problems (not switch problems)
• TCP: checksum computed in hardware, which passes yes/no to kernel
  • Linux wasn’t checking the bit in some cases!
• Three months of work to find and fix this mess

Session 4

What the heck time is it?!? (Joel Potischman)

Unfortunately, I missed a lot of this excellent talk because I was busy freaking out about my own talk. Here are the parts I remember:

• Don’t drive backward on the highway
• Eating garbage is not recommended

HDR photography in Microsoft Excel?! (Kevin Chen)

• More details here!

I got the computer to find words with good anagrams and throw away the boring ones!! (Mark Dominus)

• Finding anagrams is easy: just sort both words and compare
• Which anagrams are boring?
  • Too short
  • Compound words with the same subwords
• Metric for funness of anagrams: number of chunks in the mapping from one word to the other
  • Automatically penalizes short anagrams
  • Also penalizes anagrams with long runs of letters in the same order
• Convert the similar subsequences in the words to a graph