Anish Arora

1
Lecture 0

• Anish Arora
• CSE 6333
• Introduction to Distributed Computing

2
Distribution means

• Multiple processes (or processors) that can
  communicate with each other
• via shared memory or message channels
• Each process has only partial knowledge of system
  parameters
• loosely coupled operation, MIMD architecture
• Processes and communication are subject to faults
• Cooperation of processes to achieve a common goal
  lacks
• a shared clock
• a global shared memory
• accurate failure detection
• resource memory, time, power (sometimes)

3
Distribution goals

• Scalability
• Modularity and heterogeneity
• Data sharing
• Resource sharing
• Accommodating geography
• Reliability, fault-tolerance, security,
  timeliness, recoverability
• Low cost, better performance to cost, offloaded
  maintenance

4
Distribution challenges

• Concurrency yields complex behaviors
• Reasoning about non-determinism, about
  compositions
• Consistency/coordination despite lack of global
  state/time
• Failure is the norm and not the exception
• Spreading effects of corruption
• Many threats and several security exploit
• Economic and social impact of denial of
  service/compromise
• Scalability

5
Distribution examples

• Web servers (http)
• Peer-to-peer services and overlays
• Grid clusters, Cloud data centers
• Multi-processor and multi-core systems
• Wireless sensor network middleware and
  applications
• Network and communication protocols
• Ad hoc, mesh, mobile networks
• Three tier database servers
• Client server systems
• Distributed operating systems
• Social networks, agents

6
We will discuss

• Global time and global state
• Reasoning about distributed programs
• Problems in fault-tolerant distribution
• Wireless sensor networks
• Distributed data structures, peer-to-peer
• Systems design shared memory, message passing,
  transactional memory

7
Course approach

• Focus on common, fundamental problems
• In abstract form !
• Develop and formally specify algorithms
• Emphasize reasoning about correctness
• Properties of systems are validated thus
• Proofs also help analyze program performance
• Our focus is on deterministic reasoning
• Some lab exercises (in the context of sensor
  networks)
• You will present one published algorithmic
  concept

8
What we wont cover

• Particular distributed operating systems and
  their implementation issues (see CSE 5911,
  formerly 762)
• Programming technologies and middleware for
  distributed computing, in particular CORBA, Java
  RMI, EJB, Javaspaces, Jini, XML, and Web
  Services (see CSE 5234, formerly 769)
• Security (see CSE 5473, formerly 651) and
  Cryptography (see CSE 5351, formerly 723)
• Configuring, managing, and maintaining of
  distributed systems

9
Course materials

• Webpage http//cse.ohio-state.edu/anish/763/763.
  html
• syllabus, slides, notes, readings, assignments,
  announcements
• Well use a set of my course notes (some
  electronic, others not) and papers from the
  literature
• References
• Paul Sivilotti, Course notes, Introduction to
  Distributed Systems, 2009
• A. Kshemkalyani and M. Singhal and N. Shivaratri,
  Distributed computing Concepts, Algorithms and
  Systems, Cambridge, 2008
• Vijay K. Garg, Elements of Distributed Computing,
  Wiley, 2002
• K. M. Chandy and J. Misra, Parallel Program
  Design A Foundation, Addison-Wesley, 1988

10
What we will assume

• You should be familiar with
• Boolean (propositional and predicate) logic
• C/C and/or script programming
• I expect from you some mathematical maturity,
  including the ability to learn and use new
  mathematical programming notations (NesC for
  instance)

11
My Expectations

• Read the material assigned in class
• Work independently and ethically on homeworks and
  labs
• Ask questions

12
Grading plan

• Homework and lab assignments 25
• In class quizzes (5) 10
• Midterm quiz 25
• Presentation 15
• Take-home final quiz    25
• Working alone is a must ! Discuss questions with
  grader or me as need be
• Grading is relative. An A grade may require a lot
  less than 90