Review question 2.pdf

Ques%on: What is the purpose of system calls in an opera%ng system? A) To encrypt user data for security. B) To allow user-level processes to request services of the opera%ng system. C) To increase the processing speed of applica%ons. D) To manage network connec%ons. Correct Answer: B) To allow user...

Ques%on: What is the purpose of system calls in an opera%ng system? A) To encrypt user data for security. B) To allow user-level processes to request services of the opera%ng system. C) To increase the processing speed of applica%ons. D) To manage network connec%ons. Correct Answer: B) To allow user-level processes to request services of the opera%ng system. Explana%on: System calls provide a necessary interface between a process and the opera%ng system, allowing processes at the user level to request various services and func%ons that the OS provides. Ques%on: What is a significant advantage of the layered approach to system design? A) Faster system performance. B) It simplifies user interac%on. C) Easier to debug and modify. D) Reduced memory usage. Correct Answer: C) Easier to debug and modify. Explana%on: A layered approach allows changes to affect only specific sec%ons of the system, making it simpler to iden%fy and fix issues. Each layer has a defined func%onality, which simplifies maintenance and updates. Ques%on: In a UNIX system, what system calls are used to start a new process? A) kill() and wait(). B) fork() and exec(). C) pipe() and read(). D) chmod() and chown(). Correct Answer: B) fork() and exec(). Explana%on: The fork() system call clones the currently execu%ng process, while exec() is used to start a new process based on a different executable. This combina%on is essen%al for process crea%on in UNIX. Ques%on: What is the primary role of system programs? A) To provide a user interface. B) To manage network resources. C) To offer bundles of useful system calls. D) To encrypt and secure data. Correct Answer: C) To offer bundles of useful system calls. Explana%on: System programs offer a collec%on of system calls in a user-friendly manner, allowing users to perform common tasks without needing to write complex code. Ques%on: Why are error detec%on and handling important in an opera%ng system? A) They primarily focus on user data encryp%on. B) They ensure efficient memory alloca%on. C) They are crucial for data integrity and system reliability. D) They op%mize the system for beVer performance. Correct Answer: C) They are crucial for data integrity and system reliability. Explana%on: Error detec%on at both the hardware and soWware levels is vital to ensure that data has not been corrupted and to maintain the overall integrity and reliability of the system. Ques%on: What is the main purpose of an interrupt in an opera%ng system? A) To shut down the system in case of an error. B) To provide a way for peripheral devices to communicate with the CPU. C) To allocate more memory to processes. D) To priori%ze CPU processes. Correct Answer: B) To provide a way for peripheral devices to communicate with the CPU. Explana%on: Interrupts are signals sent to the CPU by external devices, typically to alert the CPU of a condi%on that requires its aVen%on. This mechanism allows the CPU to respond to events like input/output requests. Ques%on: What dis%nguishes a mul%tasking opera%ng system from a single-tasking one? A) The ability to run mul%ple applica%ons on a single processor. B) The use of mul%ple processors for a single task. C) Running tasks in a sequen%al, not concurrent, manner. D) The ability to perform only one task at a %me. Correct Answer: A) The ability to run mul%ple applica%ons on a single processor. Explana%on: Mul%tasking opera%ng systems can execute mul%ple tasks or processes concurrently on a single processor, giving the appearance that they are happening at the same %me. Ques%on: In opera%ng systems, what is the primary func%on of a scheduler? A) To encrypt user data. B) To distribute network resources. C) To decide which process runs at a given moment. D) To manage user permissions. Correct Answer: C) To decide which process runs at a given moment. Explana%on: The scheduler is a cri%cal part of the opera%ng system that determines which of the various processes should be execu%ng at any given %me, effec%vely managing CPU usage. Ques%on: Which of the following best describes a deadlock in an opera%ng system? A) A situa%on where mul%ple processes are wai%ng indefinitely for resources. B) An error in the kernel of the opera%ng system. C) A condi%on where a process finishes its execu%on. D) A feature for op%mizing CPU performance. Correct Answer: A) A situa%on where mul%ple processes are wai%ng indefinitely for resources. Explana%on: Deadlock occurs when two or more processes are wai%ng indefinitely for resources held by each other, leading to a halt in their execu%on. Ques%on: What is virtual memory in an opera%ng system? A) A technique to encrypt the memory content. B) Physical memory that is extended to disk storage. C) Addi%onal RAM added to the system. D) A method for priori%zing memory requests. Correct Answer: B) Physical memory that is extended to disk storage. Explana%on: Virtual memory is a memory management capability of an OS that uses hardware and soWware to allow a computer to compensate for physical memory shortages, by temporarily transferring data from random access memory (RAM) to disk storage. Ques%on: What is the typical use of a pipe in Linux? A) To extend the file system. B) To debug the kernel. C) To create a unidirec%onal communica%on channel between processes. D) To manage user permissions. Correct Answer: C) To create a unidirec%onal communica%on channel between processes. Explana%on: In Linux, a pipe is used to pass informa%on from one process to another. Pipes are unidirec%onal; data flows from the output of one process (write-end of the pipe) to the input of another (read-end of the pipe). Ques%on: What func%on is typically used to monitor the status of child processes in a Unixlike system? A) sleep() B) wait() C) exit() D) kill() Correct Answer: B) wait() Explana%on: The wait() system call in Unix-like systems is used by a process to wait for the comple%on of its child processes. It's essen%al for synchronizing the state of parent and child processes. Ques%on: What is the purpose of the waitpid() func%on in a Unix-like opera%ng system? A) To allocate memory to the process heap. B) To suspend the execu%on of the current process un%l a signal is received. C) To create a new process. D) To suspend the execu%on of the current process un%l a child process terminates or a signal is received. Correct Answer: D) To suspend the execu%on of the current process un%l a child process terminates or a signal is received. Explana%on: The waitpid() func%on allows a process to wait for and obtain the termina%on status of any child process, providing more control than the wait() func%on. Ques%on: What is the main advantage of using message queues in IPC? A) They allow for low-level hardware access. B) They provide a mechanism for processes to communicate without sharing memory. C) They enhance the graphical performance of applica%ons. D) They are used to directly manipulate file systems. Correct Answer: B) They provide a mechanism for processes to communicate without sharing memory. Explana%on: Message queues in IPC enable processes to exchange data in the form of messages, which is par%cularly useful when the communica%ng processes do not share common memory space, ensuring data is transmiVed reliably and in an ordered manner.