PhillyETE2010.mdown

Philadelphia Emerging Technologies for the Enterprise conference, April 2010

Day 1

Keynote - Bad Code, Craftsmanship, Engineering, and Certification, Bob Martin

• The only way to go fast is to go well.
• Keep functions as short, single function as possible
• Function is small enough when it can't get any smaller
• Keep argument collection small
• Avoid booleans arguments, create two functions
• Strive for simplicity = understandability
• Create a class when you create a bunch of variables in a function
• Craftsmanship is not the next big thing, it is the thing
• Test Driven Development is accepted, move on
  • Like handwashing for surgeons. People fought it. It won.
• Continuous Integration
• Pair programming
  • Do it 50 - 60% of the time, spontaneously
  • Cross training built in
• QA groups exist only because developers produce garbage
  • QA should be writing acceptance tests up front, not after
• Craftsmanship is not a management decision, it's your decision.
  • Don't ask, do work professionally.

Open source is a commercial enterprise?

• Risk: Open source could disappear
  • Many projects would survive the sponsoring companying closing shop with community support
• Risk: Open is a security risk
  • Distribution model puts more eyes on it, shakes out bugs
  • There are gatekeepers that control contributions

Rails 3 / Web 3.0

• Rails positioned it self by embracing the RESTful nature of the web.
• Areas of concern: the client
  • disconnected content, partially disconnected content
• Avoid incremental rendering, stale data is better than no data
• RESTful, Semantic HTML

Scala @ Twitter

• Twitter throws things out to see what sticks
• For person search, they launched one version in three weeks then moved onto iterative improvements
• Settled on Scala partly because it's cooler than Java

Java Concurrency / Clojure

• Functions should affect no external change
• Values are snapshots in time
• Clojure handles value immutability without much effort

Rockstar developer qualities

• Balance between humility and pride
• Awareness of one's own ignorance
• Questioning "conventional wisdom"
• The Invisible College
• Master of tools, being an optimizer not a customizer
• Discerning technology trends
• Motivation
• Knowing when it's time to change jobs
• Having a non-IT plan B
• http://ridingthecrest.com

Day 2

Keynote - The Pragmatic Cloud, Michael Coté

• Ops innovation is held back by change management.
• Operations as code - scriptability of configuration, deployment, etc
• Keep it as simple as possible to be able to deploy anywhere.

Mocks

• TDD is about gradual design and pacing (small, steady steps progress).
• Testing helps your refine what your software should do.
• Changes to code requires changes to tests.
• Mocks force you to consider how your objects will interact.
• Key point to agile: remove friction from workflow. Fix problems. Work life gets easier.

Semantic Web

• Connected vs disconnected
• Data knows about its origin, connection
• Examples: GetGlue, Twine
• SQL Data -> RDF
• Sparql querying language

Cassandra

• NOSQL = Not Only SQL
• RDBMS
  • Consistency: all nodes will report the same data at any given time
  • Difficult to scale: scale up, not up
• CAP - Consistently, availability, partition tolerance (pick 2, ditch 1)
  • RDBMS = CA
  • NOSQL = AP
• Cassandra
  • = Dynamo + BigTable
  • Column oriented
  • Auto scaling
  • Read repair
  • Location awareness
  • Gossip
    • Nodes randomly connect to cluster to get state update
  • Anti-entropy
    • Uses layered checksums to detect disk corruption
  • Fast reads
    • Mysql 100ms, Cassandra 10ms
  • Super fast writes
• Cons
  • No JOINs
  • No automatic indices
  • Thrift
• Applications: logging, batch job output, social network data

CS for Non-CS folks

• Liskov Substitution Principle
• Knuth premature optimization dictum
• Law of Demeter