GATE Daily

Tuesday27 October 2026

GATE CS & IT · 2027 · Ten questions a day

Past sets27 Oct 2026OS

Processes, threads and system calls: GATE CS question with solution

Q.8

A single process has several threads. Which of the following are shared by all the threads of this process?

One try. It counts in your 27 Oct 2026 set.
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RememberThreads of one process share the address space (code, globals, heap) and OS resources such as open files; each thread has its own program counter, registers and stack.

Solution MSQ · 1 mark · no negative marking

Answer: (A) Global variables in the data segment; (C) The table of open file descriptors

Method. Split the state into what belongs to the process and what belongs to each thread of execution.

  • Per process (shared by its threads): the address space (code, global/static data, heap), open files, and other OS resources.
  • Per thread (private): program counter, registers, stack pointer and the stack itself, thread state.

So globals (a) and the open-file table (c) are shared; the stack pointer (b) and register contents (d) are not.

The trap. The stack is in the shared address space, so another thread could reach it through a pointer; but each thread has its own stack and its own stack pointer value. "Shared address space" does not mean "shared execution context".

What was tested. The basic thread/process split: a thread is an execution context (PC, registers, stack) running inside a process's shared resources.

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