Thread Control Block (TCB) is a
data structure
In computer science, a data structure is a data organization and storage format that is usually chosen for Efficiency, efficient Data access, access to data. More precisely, a data structure is a collection of data values, the relationships amo ...
in an
operating system kernel
A kernel is a computer program at the core of a computer's operating system that always has complete control over everything in the system. The kernel is also responsible for preventing and mitigating conflicts between different processes. It is ...
that contains
thread-specific information needed to manage the thread. The TCB is "the manifestation of a thread in an operating system."
Each thread has a thread control block. An operating system keeps track of the thread control blocks in kernel memory.
An example of information contained within a TCB is:
* Thread Identifier: Unique id (tid) is assigned to every new thread
*
Stack pointer
A stack register is a computer central processor register whose purpose is to keep track of a call stack. On an accumulator-based architecture machine, this may be a dedicated register. On a machine with multiple general-purpose registers, it m ...
: Points to thread's stack in the process
*
Program counter
The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, ...
: Points to the current program instruction of the thread
* State of the thread (running, ready, waiting, start, done)
* Thread's
register
Register or registration may refer to:
Arts, entertainment, and media
Music
* Register (music), the relative "height" or range of a note, melody, part, instrument, etc.
* ''Register'', a 2017 album by Travis Miller
* Registration (organ), ...
values
* Pointer to the
Process control block
A process control block (PCB), also sometimes called a process descriptor, is a data structure used by a computer operating system to store all the information about a process.
When a process is created (initialized or installed), the operati ...
(PCB) of the process that the thread lives on
The Thread Control Block acts as a library of information about the
threads in a system. Specific information is stored in the thread control block highlighting important information about each process.
See also
*
Parallel Thread Execution
*
Process control block
A process control block (PCB), also sometimes called a process descriptor, is a data structure used by a computer operating system to store all the information about a process.
When a process is created (initialized or installed), the operati ...
(PCB)
*
Thread Environment Block
The Thread Information Block (TIB) or Thread Environment Block (TEB) is a data structure in Win32 on x86 that stores information about the currently running thread. It descended from, and is backward-compatible on 32-bit systems with, a similar s ...
(TEB)
References
{{Reflist
Operating system kernels