Protium: An Infrastructure for Partitioned Applications

1
ProtiumAn Infrastructure for Partitioned
Applications

• Cliff Young, Lakshman Y.N., Tom Szymanski, John
  Reppy, David Presotto,
• Rob Pike, Girija Narlikar, Sape Mullender and
  Eric Grosse
• Bell Laboratories, Lucent Technologies
• Presented by
• Rimon Barr
• barr_at_cs.cornell.edu
• http//www.cs.cornell.edu/barr/repository/syslunch
  /protium.ppt
• 3 May 2002

2
introduction

• quotes
• remote access feels different from local access
• consistency of long-term state
• latency and responsiveness
• why cant one use any computer on the planet?
• sounds like typical ubiquitous computing
  propaganda, but our system concretely provides
  them we have a prototype system running.
• interleaved talk
• protium
• ninja
• pulsar

3
why cant one use any computer?

• contrast stark with telephone networks
• its nearly impossible to use a neighbors
  computer
• services should reside in the network, not PC
• historical and economic reasons
• last 20 years about personal computing
• responsiveness, flexibility and the cost of
  uniformity
• networked computing environments work well
  enough
• local area networks allow for inefficiencies
• remote access tools are good enough
• despite added latency or inconsistency
• Internet, WANs grew only in the last decade
• GOAL
• to be able to use any Internet-connected
  device as if it were a machine in our office.

4
assumption about the future

• Moores Law continues
• devices
• performance, cost, size, memory capacity, disk
  capacity
• number of devices per person
• communications
• increased bandwidth
• better wireless coverage, connectivity
• latency does NOT improve

5
protium approach

• partitioned applications
• service
• hard state
• reliable
• backed up
• high availability
• viewer
• soft state
• disposable
• application specific protocol
• engineered to hide latency (eg. IMAP, Sam
  editor)
• network inside the application

6
ninja approach (berkeley)

• goal
• scalable Internet services architecture
• fault-tolerant, high-availability
• ideas
• partitioning of state across services
• service composition and paths
• applications as service path
• mobile code for service deployment
• store soft-state in the network

7
pulsar approach (rb)

• Platform for Ubiquitous Latency Sensitive
  Applicationsin Research
• goal
• componentized, latency sensitive applications
• edge computing using in-network capsules
• ideas
• capsule composition and partition of application
  state
• application is a graph of capsules
• capsules are transactional, mobile
• automatic capsule placement can
• reduce latency
• reduce bandwidth
• allow disconnected operation
• improve resource utilization
• improve scalability
• improve availability, fault-tolerance

8
protium viewers

• service can have multiple viewers
• multiplexing viewers
• session mobility
• platform independence
• infrastructure simplifies service construction
• application protocol characteristics
• mostly synchronous request-response
• read, lightweight write, heavyweight write
• ACKs and NACKs
• pub-sub semantics

9
protium prototype

• applications
• session service / view manager
• simple text editor
• MacDraw-style drawing program
• PDF image viewer
• map program
• music jukebox
• run on/written in
• Plan 9 / C
• Linux / Concurrent ML
• JVM on Windows / Java

10
protium prototype screenshots

• Plan 9

11
protium prototype screenshots

• Linux

12
protium prototype screenshots

• Windows

13
key points

• positives
• session mobility
• focus on latency
• inside the application
• working system with applications
• drawbacks
• service-viewer (or client-server)
• application protocol should be layered on
  fundamental operators with some semantics, not
  raw sockets
• no in-network processing (ninja, pulsar,
  magnetos)
• tips on how to partition
• match messages to user input
• separate control and data
• beware round-trips

14
coming soon

• infrastructure
• security authentication, encrytion
• logging, undo/redo, transactions
• caching, pre-fetching, disconnection
• naming
• managing heterogenous server machines
• real-time
• alternative viewer platforms
• text fallback allows scripting
• more applications
• PDA, conferencing, games

15
ProtiumAn Infrastructure for Partitioned
Applications

• http//www.cs.cornell.edu/barr/repository/syslunch
  /protium.ppt
• Comments, Questions
• Have a great summer!