Operating Systems Exam 2 Exam
UPDATED QUESTIONS AND CORRECT
ANSWERS
Process - CORRECT ANSWER unit of resource ownership and protection that owns resources
such as CPU, memory, files, and I/O, and provides protected access to them
Thread - CORRECT ANSWER fundamental unit of CPU utilization. basic unit of execution
within a process that the CPU schedules
What do threads share - CORRECT ANSWER Threads share the same address space, memory,
and resources of the process
What do threads not share - CORRECT ANSWER Threads do not share their stack or registers
Multithreading - CORRECT ANSWER The ability of an OS to support multiple concurrent
paths of execution within a single process
Thread benefits - CORRECT ANSWER Responsiveness, resource sharing, economy (low
overhead), and scalability on multiprocessor systems
Process creation vs thread creation - CORRECT ANSWER Process creation is heavy-weight
while thread creation is light-weight
Process Control Block (PCB) - CORRECT ANSWER Data structure that contains all
information about a process such as state, program counter, registers, and memory
Thread Control Block (TCB) - CORRECT ANSWER Data structure that contains information
about a thread including its state, registers, stack, and scheduling info
Suspending a process effect on threads - CORRECT ANSWER Suspending a process suspends
all its threads
, Terminating a process effect on threads - CORRECT ANSWER Terminating a process
terminates all its threads
Parallelism - CORRECT ANSWER Ability to perform multiple tasks simultaneously (requires
multiple cores)
Concurrency - CORRECT ANSWER Ability to make progress on multiple tasks (can occur on
single core via scheduling)
Amdahl's Law - CORRECT ANSWER Defines speedup based on serial and parallel portions
of a program
User-Level Threads (ULT) - CORRECT ANSWER Threads managed by user application,
kernel is unaware
ULT disadvantage - CORRECT ANSWER Blocking system call blocks all threads and cannot
utilize multiple cores
Kernel-Level Threads (KLT) - CORRECT ANSWER Threads managed by the operating
system and scheduled by the kernel
Many-to-One model - CORRECT ANSWER Many user threads mapped to one kernel thread,
no parallelism
One-to-One model - CORRECT ANSWER Each user thread maps to a kernel thread, allows
parallelism
Many-to-Many model - CORRECT ANSWER Many user threads mapped to many kernel
threads
Thread library - CORRECT ANSWER Provides API for creating and managing threads
UPDATED QUESTIONS AND CORRECT
ANSWERS
Process - CORRECT ANSWER unit of resource ownership and protection that owns resources
such as CPU, memory, files, and I/O, and provides protected access to them
Thread - CORRECT ANSWER fundamental unit of CPU utilization. basic unit of execution
within a process that the CPU schedules
What do threads share - CORRECT ANSWER Threads share the same address space, memory,
and resources of the process
What do threads not share - CORRECT ANSWER Threads do not share their stack or registers
Multithreading - CORRECT ANSWER The ability of an OS to support multiple concurrent
paths of execution within a single process
Thread benefits - CORRECT ANSWER Responsiveness, resource sharing, economy (low
overhead), and scalability on multiprocessor systems
Process creation vs thread creation - CORRECT ANSWER Process creation is heavy-weight
while thread creation is light-weight
Process Control Block (PCB) - CORRECT ANSWER Data structure that contains all
information about a process such as state, program counter, registers, and memory
Thread Control Block (TCB) - CORRECT ANSWER Data structure that contains information
about a thread including its state, registers, stack, and scheduling info
Suspending a process effect on threads - CORRECT ANSWER Suspending a process suspends
all its threads
, Terminating a process effect on threads - CORRECT ANSWER Terminating a process
terminates all its threads
Parallelism - CORRECT ANSWER Ability to perform multiple tasks simultaneously (requires
multiple cores)
Concurrency - CORRECT ANSWER Ability to make progress on multiple tasks (can occur on
single core via scheduling)
Amdahl's Law - CORRECT ANSWER Defines speedup based on serial and parallel portions
of a program
User-Level Threads (ULT) - CORRECT ANSWER Threads managed by user application,
kernel is unaware
ULT disadvantage - CORRECT ANSWER Blocking system call blocks all threads and cannot
utilize multiple cores
Kernel-Level Threads (KLT) - CORRECT ANSWER Threads managed by the operating
system and scheduled by the kernel
Many-to-One model - CORRECT ANSWER Many user threads mapped to one kernel thread,
no parallelism
One-to-One model - CORRECT ANSWER Each user thread maps to a kernel thread, allows
parallelism
Many-to-Many model - CORRECT ANSWER Many user threads mapped to many kernel
threads
Thread library - CORRECT ANSWER Provides API for creating and managing threads
