COS226 - Lecture - Concurrent Objects - 1

COS226 - Lecture - Concurrent Objects - 1 - COS226:...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
COS226: Concurrent Systems Chapter 3: Concurrent Objects Part 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Concurrent Objects Best described by safety and liveness or correctness and progress properties; What is correctness? Refer to Figure 3.2.
Background image of page 2
Sequential Objects APIs are documented using sequential specification : preconditions; postconditions.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Sequential Objects Queue contains sequence q (precondition); A call to enq(z) appends z to q; Queue contains sequence q . z (postcondition).
Background image of page 4
Quiescent Consistency Method calls take time; A method call is an interval started by an invocation and ending with a response ; A method is pending if it has been invoked but has not yet responded. Refer to Figure 3.4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Quiescent Consistency Principle 3.3.1: Methods should appear to happen in a 'one-at-a-time' sequential order; Principle 3.3.2: Methods separated by a period of quiescence should appear to take effect in their real-time order.
Background image of page 6
Suppose x and y are concurrently enqueued; The queue becomes quiescent; z is enqueued. Example: shared counter.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 14

COS226 - Lecture - Concurrent Objects - 1 - COS226:...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online