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.

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • PCI DSS (Payment Card Industry Data Security Standard)

    The Payment Card Industry Data Security Standard (PCI DSS) is a widely accepted set of policies and procedures intended to ...

  • risk management

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

  • compliance framework

    A compliance framework is a structured set of guidelines that details an organization's processes for maintaining accordance with...

SearchSecurity

  • Trojan horse (computing)

    In computing, a Trojan horse is a program downloaded and installed on a computer that appears harmless, but is, in fact, ...

  • identity theft

    Identity theft, also known as identity fraud, is a crime in which an imposter obtains key pieces of personally identifiable ...

  • DNS over HTTPS (DoH)

    DNS over HTTPS (DoH) is a relatively new protocol that encrypts domain name system traffic by passing DNS queries through a ...

SearchHealthIT

  • telemedicine (telehealth)

    Telemedicine is the remote delivery of healthcare services, such as health assessments or consultations, over the ...

  • Project Nightingale

    Project Nightingale is a controversial partnership between Google and Ascension, the second largest health system in the United ...

  • medical practice management (MPM) software

    Medical practice management (MPM) software is a collection of computerized services used by healthcare professionals and ...

SearchDisasterRecovery

SearchStorage

  • M.2 SSD

    An M.2 SSD is a solid-state drive (SSD) that conforms to a computer industry specification and is used in internally mounted ...

  • kilobyte (KB or Kbyte)

    A kilobyte (KB or Kbyte) is a unit of measurement for computer memory or data storage used by mathematics and computer science ...

  • virtual memory

    Virtual memory is a memory management capability of an operating system (OS) that uses hardware and software to allow a computer ...

Close