WBJECA 2025 — Computer PYQ
WBJECA | Computer | 2025In an operating system, a thread is best described as
Choose the correct answer:
- A.
A program in execution.
- B.
The smallest unit of CPU scheduling.
(Correct Answer) - C.
A process that has finished execution.
- D.
A collection of processes.
The smallest unit of CPU scheduling.
Explanation
In modern operating systems, a thread (often called a lightweight process) is the basic unit of CPU utilization. It comprises a thread ID, a program counter, a register set, and a stack.
To understand why option (B) is correct, consider the distinction between a process and a thread:
Process: A process is a program in execution (which makes option A the definition of a process, not a thread). It is a heavy-weight unit of resource allocation that owns its own memory space and system resources.
Thread: A thread exists within a process. Multiple threads can exist within a single process, sharing the same memory space and resources, but each thread maintains its own execution state. Because they are "lightweight," the OS scheduler can switch between threads much faster than between full processes.
The relationship can be visualized as follows:
Execution State={Thread ID,Program Counter,Registers,Stack}