Independent Threads

• no states shared with other threads
• Deterministic computation
  • Output depends on the input
• Reproducible
  • output does not depend on the order and timing of other threads

Cooperating Threads

• Shared states
• _Nondeterministic
• Nonreproducable
• shared resources
• speedup
  • occurs when threads use different resources at the same times
• Modularity
  • an application can be decomposed into threads
• if threads work on different data the scheduling doe not matter
  • unless one relys on anothers data :)
  • race conditions occur when threads share data, and their results depend on timing of executions

Atomic Operations

• an atomic operation always runs to completion; all or nothing
• Many operations are not atomic