Correction from last time – HVAC – Heating, Ventilation and Air Conditioning. Thanks Tim! (no, really) History 1975 – First self contained digital camera. 100px by 100px (0.01 megapixels) – By who? Any guesses? CCD sensor. Took 23 seconds to record an image 1981 – Sony Mavica camera. 0.72mp. Recorded to floppy disk. CCD 1999 – Nikon D1 – First DSLR. 2.74mp 2000 – Canon EOS D30. 3.25mp CMOS sensor 2001 – 5MP 2007 – 12MP 2009 – 18MP 2016 – Canon 5DSR – 50MP How do they work? Each pixel is...

1932 Jay B. Nash  “Within our grasp is the leisure of the Greek citizen, made possible by our mechanical slaves, which far outnumber his twelve to fifteen per free man… As we step into a room, at the touch of a button a dozen light our way. Another slave sits twenty-four hours a day at our thermostat, regulating the heat of our home. Another sits night and day at our automatic refrigerator. They start our car; run our motors; shine our shoes; and cult our hair. They practically eliminate...

Authentication vs. Authorization One-factor, “something you know” Cleartext, hashes, salts Entropy, complexity https://xkcd.com/936/ Two-factor, “something you have, something you know” Tokens, sms, totp Back them up! Authy will do this for you. Good/bad practices Don’t use things that can be gained by social engineering Your dogs name Mother’s maiden name Keys close together on the keyboard are bad (sequences like 12345, qwerty, etc) Don’t use dictionary words Don’t replace letters...

History Before 1925 all audio recording was strictly mechanical 1860 recording with charcoal and paper – https://en.wikipedia.org/wiki/File:1860-Scott-Au-Clair-de-la-Lune-05-09.ogg 1885 – Disc Phonograph incl recording of Alexander Graham Bell’s voice – https://en.wikipedia.org/wiki/Volta_Laboratory_and_Bureau#Bell.27s_voice Became the Vinyl that we know Til 1945 – Electric but still recorded onto wax discs as master Magnetic recording onto tape and became the standard after 1950 1975 –...

  WLAN – Wireless Local Area Network. Takes wired networks and makes them wireless. Above the data link later (layer 2), it’s the same as wired. Uses public use license radio frequencies. Usually 2.4ghz and 5GHz. Also 24GHz. History Hedy Lamarr The Way I heard it Podcast Link ALOHA NET – 1971.  WaveLAN – 1991 – NCR/AT&T IEEE 802.11 – 1997 Institute of Electrical and Electronics engineers 802.11n – 2009 802.11ac – 2013 2.4GHz vs 5GHz vs 60GHz Long range 802.11 vs “Microwave”...

History 1957 – American Physicists monitoring Sputnik – noticed doppler effect. Explain doppler TRANSIT, OMEGA, Timation, etc 1973 – Defense Navigation Satellite System (DNSS) 1983 – President Reagan made GPS freely available to the public after  Korean Air Lines Flight 007, a Boeing 747 carrying 269 people, was shot down after straying into the USSR’s prohibited airspace. Selective availability – May 1 2000, Clinton Now – cars, planes, phones, etc Tech Wiki: The GPS concept is based on...

Cables Pretty much always fibre, with the very last bit copper (be it a home user on DSL, but that’s changing, or the ethernet cable to a system. Very few servers historically directly had fibre, but it is becoming a lot more common – due to bandwidth) For long distances – travels better than electrical signals. Ground issues For short distances – electrical isolation Modems – essentially media converters. Copper -> Copper Fibre -> Copper Wireless -> Copper Routing Each...