CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which problem can occur when multiple threads update shared data without proper synchronization?
A. Boot failure
B. Disk fragmentation only
C. Page coloring
D. Race condition
Correct Answer: D
A race condition arises when results depend on uncontrolled timing of concurrent accesses.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Compared with a user-level thread, a kernel-level thread is:
A. Known and scheduled directly by the operating-system kernel
B. Invisible to all operating-system components
C. Stored only on disk
D. Always faster in every situation
Correct Answer: A
Kernel threads are represented and scheduled by the kernel.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which of the following is a key reason processes need inter-process communication?
A. The CPU cannot execute processes
B. Processes often need to exchange data and coordinate actions
C. Every process has the same memory automatically
D. Processes cannot access files
Correct Answer: B
IPC mechanisms enable data exchange and synchronization between separate processes.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which term describes the creation of a child process by an existing process?
A. File journaling
B. Disk striping
C. Process creation
D. Page replacement
Correct Answer: C
Operating systems allow processes to create child processes, forming process hierarchies.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
What does the Process ID (PID) identify?
A. A file extension
B. A disk sector
C. A memory page size
D. A running process
Correct Answer: D
The PID is the numeric identifier the operating system assigns to a process.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
A daemon in Unix/Linux is best described as:
A. A background service process
B. A deleted process
C. A graphical desktop icon
D. A disk partition
Correct Answer: A
Daemons run in the background to provide system or network services.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which Unix-like operation commonly replaces the current process image with a new program?
A. mount
B. exec family
C. mkdir
D. grep
Correct Answer: B
The exec family loads a new executable into the current process.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which system call conceptually creates a new process by duplicating the calling process on Unix-like systems?
A. chmod()
B. printf()
C. fork()
D. open()
Correct Answer: C
fork() creates a child process derived from the calling process.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
On Unix-like systems, a child process whose parent terminates first is commonly called an:
A. Kernel thread
B. Zombie only
C. Critical process
D. Orphan process
Correct Answer: D
An orphan process continues after its parent exits and is adopted by a system process.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
A process that has completed but still has an entry in the process table awaiting collection by its parent is called a:
A. Zombie process
B. Daemon
C. Orphan thread
D. Boot process
Correct Answer: A
On Unix-like systems, a zombie has exited but its termination status has not yet been reaped.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
What is a major advantage of multithreading within one process?
A. It guarantees one thread per CPU
B. Lower communication and switching overhead than separate processes
C. It prevents all race conditions automatically
D. It removes the need for scheduling
Correct Answer: B
Threads share resources, making creation, switching, and communication comparatively efficient.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which item is normally private to each thread?
A. All open files
B. Executable code segment
C. Stack and CPU register state
D. Entire process address space
Correct Answer: C
Each thread needs its own stack, program counter, and register context.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Threads within the same process usually share which resource?
A. Separate physical computers
B. Different kernels
C. Different file systems by definition
D. Address space and open process resources
Correct Answer: D
Threads of one process share code/data/address space while maintaining separate execution states.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Why is excessive context switching undesirable?
A. It consumes CPU time without directly doing application work
B. It permanently increases RAM capacity
C. It eliminates interrupts
D. It makes all processes real-time
Correct Answer: A
Saving/restoring execution state is overhead, so too many switches reduce useful CPU time.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
What is a context switch?
A. Moving a file between folders
B. Saving the state of one process or thread and restoring another
C. Converting source code into machine code
D. Changing a file extension
Correct Answer: B
A context switch lets the CPU change from one execution context to another.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which process state indicates that execution has completed?
A. Waiting
B. New
C. Terminated
D. Ready
Correct Answer: C
A terminated process has finished or has been explicitly stopped.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which transition occurs when the scheduler selects a process from the ready queue for execution?
A. Running to Waiting
B. Waiting to New
C. Terminated to Ready
D. Ready to Running
Correct Answer: D
Dispatching moves a selected ready process onto the CPU.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
A process normally changes from Running to Waiting/Blocked when:
A. It requests an event such as I/O that is not yet complete
B. Its time quantum expires
C. It is selected by the dispatcher
D. It completes execution
Correct Answer: A
Blocking occurs when a process cannot proceed until an event or resource becomes available.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
A process changes from Running to Ready most directly when:
A. Its file is deleted
B. It is preempted by the scheduler
C. It requests blocking I/O
D. It terminates
Correct Answer: B
Preemption removes a running process from the CPU while leaving it ready to continue.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which data structure stores information such as a process state, program counter, registers, and scheduling data?
A. Boot sector
B. Translation Lookaside Buffer
C. Process Control Block (PCB)
D. File Allocation Table
Correct Answer: C
The PCB contains the operating system's management information for a process.