• Cloud Computing
• Tom Hanlon (Cloudera)

attendance: 70

http://zookeeper.apache.org/

He learned Zookeeper via HBase (uses Zookeeper to manage HA)

questions

• who is in charge — am I – are we both (i.e., "split brain")?
• what to do when starting back up after failure?
• what is the state of process X?
• how to elect primary from a group of peers?

services

• distributed lock mgmt
• master election (others become read-only replicas)
• time-based info sharing
• hierarchy mgmt (e.g., startup order)

built by Yahoo

Zookeeper : distributed metadata filesystem

• tree-based
• each node up to 1MB data
• node can have children
• nodes cannot be renamed
• no hard/soft links
• guaranteed
  • ordered updates, conditional updates, watches

Zookeeper

• can generate nodenames to avoid collisions
• can build "presence" awareness systems using emphemeral nodes (nodes
  that exist as long as you are connected)

Zookeeper

• naming; synchronization; leader election; group mgmt

details

• filesystem like abstraction with a tree of znodes
  • each node can hold data and other nodes
• znode atomic/persistent/ordered ops: create; delete; exists; get/set data; get children; sync
• ACL on each node

See

• http://en.wikipedia.org/wiki/Paxos_{(computerscience)}
• http://labs.google.com/papers/chubby.html

• Open Data
• Tags: open_gov, mapping, open_data, participatory_culture, apps, education, couchdb, crowdsourcing, mobile_apps, licensing
• Matt Blair (Elsewise LLC)

attendance: 16

http://mattblair.net/

Challenge: How do you get the community to be excited about and
participate in open datasets?

project goals

• free apps for public education/participation
• creation of real-time geo-queryable
• maintained open datasets (can be used by other projects)
• data preserved - so can be used by other apps in future

broader

• learning/exploring
• appreciation of place (Portland)
• participation

three projects

• http://poetrybox.info/
  • but no list of locations
  • no one agrees on what these things are called?
• http://pdxtrees.org/
  • make statistical data exciting — encourage participation/engagement?
  • gather a community-wide collection of photos of Portland’s Heritage Trees
• http://publicartpdx.com
  • blend data from multiple formats/agencies
  • make sure it points to the right place

common themes

• crowd-correcting locations
• managing community contributions
• The importance of sustainable, re-usable datasets (i.e. an iOS app
  is just this year’s packaging)
• Mobile devices as data collectors
• Mobile app users as data submitters, correctors and curators
• Making use and participation easy for non-technical people
• CouchDB as canonical datastore
• The complexities of intellectual property and local government data
• The use of government data as scaffolding, a framework which the
  public can improve and adorn

building datasets (BIG TASK)

• screen-scrape; repurpose feeds; …
• web forms, but most people end up sending an email/tweet/groupMsg

avoid scope creep

• build the least functional version; rapid feedback cycles

multiple sources of info

• who gathered it?
• to what end (profit)?
• are they maintaining it?
• do they want to share?

data

• start small
• find allies and implement an example
• don't wait for perfect dataset
• …

data formats

• metadata; schema; noisy; shifting standards; restrictions; data
  provider

less about architecture than improvisation

CouchDB

• has GeoCouch built-in
• eventual consistency
• allows you to delay schema decisions (but there is always an
  implicit schema)

just because it is open doesn't mean it's accessible

• make it attractive and compelling

roles: collection; scrubbing; research and verification; curation;
authority; advocacy;

data has stories : when you share, interpretations emerge

data is your platform

• everything else is ephemeral (e.g., web site, iOS app)
• plan for data use by different infrastructure in N years

• Tools and Techniques
• Tags: scm, git, kernel_org, android
• John Hawley (Linux Foundation / Kernel.org), Shawn Pearce (Google)

attendance: 60

rejected subversion: single server/point-of-control; difficult to fork

chose Git instead (DVCS) : easy to develop independently and share
when ready

Android OS

• 275 Git repos: 4.4 GB
• floating HEAD (lastest version)

Gerrit Code Review

• Apache License 2.0
• self-contained
  • embedded jetty
  • embedded H2 SQL database
  • embedded JGit impl
• works with hudson/jenkins
• ACL; LDAP; OpenID

http://android.git.kernel.org

git is fast if

• on a laptop/desktop
• lots of RAM
• fast disk
• only working in one repo

git uses lots of RAM

gitweb does caching

http://review.source.android.com -git push-> kernel.org -cron+rsync-> frontend nodes

stats

• 1M git protocol actions/day
• 200K web hits/day

• Tags: brains, cognition, wetware, humour
• Paul Fenwick (Perl Training Australia)

attendance: 100s

1978 perception experiment : severed split-brain

• right eye sees chicken leg and pick chicken; left does right
• then ask why : reversed explanation
• speech is from X-side : makes things up but feel like a real memory
• not special to people with brain surgery

salespeople know more about how brains work and how to trick them

priming : setup test to looks like real psych experiment

• give you leading tests to influence you
• add priming words that get person to think in certain way
• rude priming can cause people to interrupt more
• old priming: people take longer to walk to elevator
• when asked: did the word puzzle influence you? — they say no

thinking is for doing

pricing

• write down last 2 digits of SSN
• causes people to pay more if they have higher numbers

comparison

• company had one item - not selling well
• built a larger more pricey version to put on shelf next to slimmer less expensive version (decoy)
• now small/cheaper sold like crazy

magazine

• internet only = $59
• print only = $125 (decoy)
• internet + print = $125 (this sells)

if you want to be selected for something

• find someone who is similar to you but not as cool

remember the future: imagination (reuses existing brain architecture)

but reality first (and important survival skill)

• if visual or audio or X center occupied then can't imagine
• but, we don't always realize when our emotional centers are being used for something else
• emotional architecture: emotional centers for pain are same as physical centers for pain

two-factor theory of emotion

• when scared: elevated heartrate, dialated eyes, …
• look for cues on why you are scared
• fall in love with rescuer