Browse Definitions :
Definition

sequential consistency

In computers, sequential consistency is best defined by its inventor, Leslie Lamport, who declared that a multiprocessing system had sequential consistency if:

"...the results of any execution is the same as if the operations of all the processors were executed in some sequential order, and the operations of each individual processor appear in this sequence in the order specified by its program."
This definition was one of the first statements on what constituted "correct" behavior for a symmetric multiprocessing ( SMP ) system. It has been restated in various forms, among them the following:
Sequential consistency requires that a shared memory multiprocessor appear to be a multiprogramming uniprocessor system to any program running on it.
Sequential consistency requires that:

1. All instructions are executed in order.

2. Every write operation becomes instantaneously visible throughout the system.

Implicit in the definition of sequential consistency was the acknowledgement that SMP systems could fail to be sequentially consistent. Should machines be sequentially consistent? From the vantage point of almost twenty years later, the answers are mixed. Some say "yes", that machines should conceal implementation complexities in order to make the machines as easy to use as possible. Others say "no", that violating SC allows machines to increase performance considerably while at the same time inconveniencing only a vanishingly small number of programmers.

This was last updated in November 2005

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

  • risk management

    Risk management is the process of identifying, assessing and controlling threats to an organization's capital and earnings.

  • compliance as a service (CaaS)

    Compliance as a Service (CaaS) is a cloud service service level agreement (SLA) that specified how a managed service provider (...

  • data protection impact assessment (DPIA)

    A data protection impact assessment (DPIA) is a process designed to help organizations determine how data processing systems, ...

SearchSecurity

  • computer worm

    A computer worm is a type of malicious software program whose primary function is to infect other computers while remaining ...

  • Single Sign-On (SSO)

    Single sign-on (SSO) is a session and user authentication service that permits a user to use one set of login credentials (e.g., ...

  • Certified Information Systems Auditor (CISA)

    Certified Information Systems Auditor (CISA) is a certification issued by ISACA to people in charge of ensuring that an ...

SearchHealthIT

SearchDisasterRecovery

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • disaster recovery team

    A disaster recovery team is a group of individuals focused on planning, implementing, maintaining, auditing and testing an ...

  • cloud insurance

    Cloud insurance is any type of financial or data protection obtained by a cloud service provider. 

SearchStorage

Close