Browse Definitions:
Definition

thread

Contributor(s): Rene Martinez

1) On the Internet in Usenet newsgroups and similar forums, a thread is a sequence of responses to an initial message posting. This enables you to follow or join an individual discussion in a newsgroup from among the many that may be there. A thread is usually shown graphically as an inital message and successive messages "hung off" the original message. As a newsgroup user, you contribute to a thread by specifying a "Reference" topic as part of your message.

2) In computer programming, a thread is placeholder information associated with a single use of a program that can handle multiple concurrent users. From the program's point-of-view, a thread is the information needed to serve one individual user or a particular service request. If multiple users are using the program or concurrent requests from other programs occur, a thread is created and maintained for each of them. The thread allows a program to know which user is being served as the program alternately gets re-entered on behalf of different users. (One way thread information is kept by storing it in a special data area and putting the address of that data area in a register. The operating system always saves the contents of the register when the program is interrupted and restores it when it gives the program control again.)

A thread and a task are similar and are often confused. Most computers can only execute one program instruction at a time, but because they operate so fast, they appear to run many programs and serve many users simultaneously. The computer operating system gives each program a "turn" at running, then requires it to wait while another program gets a turn. Each of these programs is viewed by the operating system as a task for which certain resources are identified and kept track of. The operating system manages each application program in your PC system (spreadsheet, word processor, Web browser) as a separate task and lets you look at and control items on a task list. If the program initiates an I/O request, such as reading a file or writing to a printer, it creates a thread. The data kept as part of a thread allows a program to be reentered at the right place when the I/O operation completes. Meanwhile, other concurrent uses of the program are maintained on other threads. Most of today's operating systems provide support for both multitasking and multithreading. They also allow multithreading within program processes so that the system is saved the overhead of creating a new process for each thread.

The POSIX.4a C specification provides a set of application program interfaces that allow a programmer to include thread support in the program. Higher-level program development tools and application subsystems and middleware also offer thread management facilities. Languages that support object-oriented programming also accommodate and encourage multithreading in several ways. Java supports multithreading by including synchronization modifiers in the language syntax, by providing classes developed for multithreading that can be inherited by other classes, and by doing background "garbage collection" (recovering data areas that are no longer being used) for multiple threads.

This was last updated in September 2005

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...

  • risk assessment

    Risk assessment is the identification of hazards that could negatively impact an organization's ability to conduct business.

SearchSecurity

  • phishing

    Phishing is a form of fraud in which an attacker masquerades as a reputable entity or person in email or other communication ...

  • vulnerability disclosure

    Vulnerability disclosure is the practice of publishing information about a computer security problem, and a type of policy that ...

  • incident response

    Incident response is an organized approach to addressing and managing the aftermath of a security breach or cyberattack, also ...

SearchHealthIT

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • business continuity plan (BCP)

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

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

SearchStorage

  • flash memory

    Flash memory, also known as flash storage, is a type of nonvolatile memory that erases data in units called blocks.

  • NAND flash memory

    NAND flash memory is a type of nonvolatile storage technology that does not require power to retain data.

  • NOR flash memory

    NOR flash memory is one of two types of nonvolatile storage technologies.

SearchSolidStateStorage

  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.

Close