WebFund 2014W Lecture 18

The video from the lecture given on March 19, 2014 is available:

• Small from screencast.com
• Large from screencast.com
• Original from CUOL

invoke versus call

• SAME THING

Reactor pattern

• direct contrast to a procedural pattern
• procedural: everything is synchronous
  • each line completes before the next executes
• reactor pattern: mostly synchronous
  • exception: event handlers
  • dispatcher calls event handlers
• type of event-driven programming
  • event dispatcher is implicit
  • implicit "assembly line"
  • raw data comes in, dispatcher has routine(s) that match raw data
  • routine process it, leaves processed data
  • processed data matches other routines
• normal events are incoming I/O events
  • keypresses, mouse clicks, network traffic
• node makes use of synthetic events
  • generated by other code

multitasking

• node is "cooperatively multitasked"
• multithreaded code is preemptively multitasked
• sane multithreading involves locking
  • temporary exclusive ownership
  • mistakes lead to race conditions
• node avoids race conditions while being highly concurrent
  • node is fast