Combine OSG 1-2-3-4-5-6-7
A CPU may have separate fetch, decode and execute units, so that can carry out three steps of the three instructions in the same time is called: Pipeline Superscalar Multicore None of the other choices
A
Assume jobs A-D arrive in quick succession in the READY queue. Using round robin scheduling (quantum=4), the turnaround time for job B is ____. Arrival time: 0 1 2 3 Job: A B C D CPU cycle: 8 4 9 5 7 20 22 24
A
Five batch jobs A through E, arrive at a computer center at almost the same time. They have estimated running times of 8, 6, 2, 10, and 4 minutes. Determine the average turnaround time for SJF (Shortest job first) scheduling. Ignore process switching overhead. 14 minutes 8 minutes 6 minutes 18.8 minutes
A
Five batch jobs A through E, arrive at a computer center at almost the same time. They have estimated running times of 8, 6, 2, 10, and 4 minutes. Their (externally determined) priorities are 3, 5, 2, 1, and 4, respectively, with 5 being the highest priority. Determine the average waiting time for Priority scheduling. Ignore process switching overhead. 10,8 minutes 12,8 minutes 16,8 minutes 54 minutes
A
Semaphores that are initialized to 1 and used for two or more processes to ensure only one can enter its critical section at the same time are called: Binary semaphores Integer semaphores Counter semaphores None of the other choices
A
The language of the CPU is known as its Instruction set Register set Control unit set None of the other choices
A
The two basic types of processor registers are: General and special registers Control and Status registers User-visible and user-invisible registers None of the other choices
A
What happens when a thread calls Down (S) when it wants to enter its critical section, where S is a binary semaphore set to 1? The thread is allowed to enter its critical section and S is decremented. The thread is blocked and added to a queue of waiting threads. The semaphore is set to 2. None of the other choices
A
What is the purpose of CPU scheduling algorithms? Pick one of the ready processes to run next Put to sleep and wake up processes in an efficient manner Allocate memory to the processes in a fair and efficient way None of the other choices
A
Where is the position of the operating system in computer system: Above the hardware and under the user interface program Between the user interface program and the application Program In user space None of the other choices
A
Which of the following actions generates an external interrupt? An input/output operation is completed. A page that does not exist in the main memory is accessed by the virtual storage management. A system call instruction is executed. Division by zero occurs.
A
Which of the following instructions should be allowed only in kernel mode? Disable all interrupts Read the time-of-day clock AND of two numbers ADD of two numbers
A
Which of the following statements about Electrically Erasable PROM (EEPROM) is correct? Can be erased and rewritten Volatile Unprogrammable None of the other choices
A
A CPU may have multiple execution units, so that can carry out multiple instructions in the same time is called: Pipeline Superscalar Multicore None of the other choices
B
A special register that contains the address of the next instruction to be fetched is called: Instruction Register (IR) Program Counter (PC) Program Status Word (PSW) All of the other choices
B
Assume that four jobs A-D require the CPU cycles listed below. Using the Shortest Job First algorithm, the ____ job is run first. Arrival time: 4 1 0 2 Job: A B C D CPU cycle: 5 2 6 4 A B C D
B
Five batch jobs A through E, arrive at a computer center at almost the same time. They have estimated running times of 8, 6, 2, 10, and 4 minutes. Determine the average waiting time for SJF (Shortest job first) scheduling. Ignore process switching overhead. 14 minutes 8 minutes 6 minutes 18.8 minutes
B
Information that must be saved prior to the processor transferring control to the interrupt handler routine includes: PSW PSW and PC PSW and Contents of processor registers None of the other choices
B
The first-come, first-served (FCFS) algorithm is fine for most ____ systems Interactive Batch Real time Multiuser
B
The general role of an operating system is to: Act as an interface between various computers Provide a set of services to system users Manage files for application programs None of the other choices
B
What is Higher-level proposal in the solution of Mutual exclusion and Synchronization? Message passing Monitors Peterson's Solution Disable Interrupts
B
What is the purpose of process synchronization? Let different users run different processes independently Avoid race condition Avoid deadlock None of the other choices
B
Which is a method of interprocess communication that use two primitive send and receive? Lock variables Message passing Peterson's algorithm Semaphores
B
Which of the following is a preemptive scheduling algorithm FCFS Shortest Job First Round Robin None of the other choices
B
Which of the following is correct about Shortest Job First scheduling algorithm? Avoid Starvation Minimize average waiting time Avoid Starvation and Minimize average waiting time None of the other choices
B
Which of the following is not a CPU scheduling criterion? CPU utilization Burst time Throughput Response time
B
Which of the following statements about Random Access memory (RAM) is correct? Is typically faster than cache memory Is volatile Can only be read sequentially Stores all the files on the computer
B
Which one cannot be able to solve the race condition? TSL Shared memory Semaphore Monitor
B
A CPU may have two or more complete processors, so that can carry out multiple threads in the same time is called: Pipeline Superscalar Multicore None of the other choices
C
As one proceeds down the memory hierarchy (from inboard memory to offline storage), the following conditions apply: Decreasing cost per bit Increasing capacity Increasing access time All of the other choices
C
As one proceeds down the memory hierarchy (from inboard memory to offline storage), which of the following conditions is correct? Increasing cost per bit Decreasing capacity Increasing access time None of the other choices
C
List of memory location, that contains the executable program, the program's data, and its stack is called: set of resources address space address memory All of the other choices
C
The four main structural elements of a computer system are: Processor, Registers, I/O Modules, Main Memory Processor, Registers, Main Memory, System Bus Processor, Main Memory, I/O Modules, System Bus None of the other choices
C
What is interrupt vector? A signal an I/O device sends to CPU The addresses of interrupt handlers Part of memory which contains the addresses of interrupt handlers None of the other choices
C
What is not a main function of an operating system? Provide the users with an extended (virtual) machine Manage the I/O devices Provide user interfaces Support virtual memory
C
Which is not a goal of a scheduling algorithm for real-time systems? Meeting deadlines Predictability Fairness None of the other choices
C
Which is not an example of a resource that is commonly space-multiplexed? CPU Video RAM Hard drive Main memory
C
Which of special register contains the condition code bits, the CPU priority, the mode bit and other control bits? Instruction Register (IR) Program Counter (PC) Program Status Word (PSW) None of the other choices
C
Which of the following conditions of semaphore variable "s" implies a busy critical region? s > 0 s < 0 s = 0 None of the other choices
C
Which of the following is not a step in the boot process? Configuration and customization settings are checked. The BIOS is activated by powering on the CPU. The antivirus program checks all files for viruses. The operating system is loaded into RAM.
C
Which of the following statements is incorrect about the CMOS? Is volatile Interrupt To contain BIOS To hold the configuration parameters
C
An operating system Manages hardware resources in a computer system Manages software resources in a computer system Deals with complex hardware resources and provides the user a virtual/extended machine that is much easier to deal with than the physical machine All of the other choices
D
Booting a general purpose computer involves the following steps except Execution of a ROM-based POST sequence Loading one or more bootstrap loaders Loading the OS Loading the command interpreter
D
Examples of general purpose stored program computers include the following except Personal computers Network servers Workstations MP3 player
D
Five batch jobs A through E, arrive at a computer center at almost the same time. They have estimated running times of 8, 6, 2, 10, and 4 minutes. . Determine the average waiting time for FCFS scheduling. Ignore process switching overhead. 17 minutes 18 minutes 18.8 minutes 12,8 minutes
D
The ways that input/output can be done is? Busy waiting Interrupt DMA (Direct Memory Access) All of the other choices
D
What is Software proposal in the solution of Mutual exclusion with Busy waiting? Message passing Monitors Peterson's Solution All of the other choices
D
Which is not a goal of a scheduling algorithm for batch systems? CPU utilization Throughput Turnaround time Response time
D
Which is true about Mutex? A simplified version of the semaphore when the semaphore's ability to count is not needed Is good only for managing mutual exclusion to some shared resource or piece of code Is a variable that can be in one of two states: unlocked or locked All of the other choices
D
Which of special register in the CPU points to the top of the current stack in the memory? IR PC PSW SP
D
Which of the following is not a operating mode of CPU User mode Kernel mode Management mode None of the other choices
D
Which of the following is true about Atomic action on semaphores? Checking the value Changing the value Possibly going to sleep All of the other choices
D
Which of the following statements about semaphores is true? P and V (Down and Up) operations should be indivisible operations If several processes attempt a P(S) operation simultaneously, only one process should be allowed to proceed. A semaphore implementation should guarantee that processes do not suffer indefinite postponement. All of the other choices
D
Which of the following statements about the CPU handling interrupts is incorrect? The processor ceases to execute the current sequence of instructions The hardware saves the old PC location The CPU branches to a new instruction sequence None of the other choices
D
Which of the following synchronization mechanisms does not rely on busy-waiting? Lock variables Strict alternation Peterson's algorithm Semaphores
D
Which statement about disabling interrupts to resolve race conditions is wrong? In theory, a program can disable interrupts when it enters a critical section, and re-enable interrupts when finished with a critical section, to eliminate race conditions. Disabling/enabling interrupts may negatively affect the I/O system. Programs with infinite loops in their critical sections are a significant problem with the interrupt-based approach. User-mode programs are the best place to invoke disableInterrupt().
D
____ is the act of allowing only one process to have access to a dedicated resource No preemption Circular wait Resource holding Mutual exclusion
D
Which of the following conditions must be held to provide good solution for mutual exclusion? No two processes simultaneously in critical region No assumptions made about speeds or numbers of CPUs No process running outside its critical region may block another process No process must wait forever to enter its critical region All of the other choices
E
Critical Region (Section) concept used in interprocess communication is: a. A part of the program where the shared memory is accessed b. A part of shared data c. A part of shared memory d. None of the other choices
a
In order to implement mutual exclusion on a critical resource for competing processes, only one program at a time should be allowed: a. In the critical region of the program b. To perform message passing c. To exhibit cooperation d. None of the above
a
QN=11 (6931) OS Win32 use system call_____, while OS Unix use system call______ to create a new process a. CreateProcess; fork b. fork, CreateProcess c. copy, CreateProcess d. CreateProcess; copy
a
QN=15 (6966) Which conditions of mutual exclusion does the Lock Variables (Software proposal) violate? a. No two processes simultaneously in critical region b. No assumptions made about speeds or numbers of CPUs c. No process running outside its critical region may block another process d. No process must wait forever to enter its critical region
a
Which of the events that causes the processes to be created, when an operation system is booted? System initialization Execution of a process creation system call User request to create a new process Initiation of a batch job
a
Which of the following conditions that causes the processes to be terminated, when the processes executes a system call tell the OS to finish some other process? Normal exit (voluntary ) Error exit (voluntary) Fatal error (involuntary) Killed by another process (involuntary)
a
Which of the following process state transitions is correct, when the operating system discovers that process cannot continue right now because of is not enough resource? Running -> Blocked (waiting) Running -> ready Blocked (waiting) -> ready Ready -> running
a
Which of the following statements is a hardware solution to the critical region problem? a. TSL b. Shared memory c. Semaphore d. None of the other choices
a
A ____ is a portion of a process that can run independently. [A] subprocess [B] thread [C] program [D] Mini-process
b
A process where no concurrency inside process; everything happens sequentially is called : Random access process Sequential process Sequential access process None of the other choices
b
An arrival message causes the system to create a new thread to handle this message. This new thread is call [A] Activator [B] Pop-up [C] Upcall [D] Distributed
b
Critical Region (Section) concept used in interprocess communication is: [A] A part of shared memory [B] A part of the program where the shared memory is accessed [C] None of the other choices [D] A part of shared data
b
How many percent of the CPU time is wasted, when a computer system has enough room to hold two program and these programs are idle waiting for I/O half the time? a. 50% b. 25% c. 75% d. None of the other choices half the time ==> 50% = x process = 2 = y %waste = x%^y ==> 50%^2 = 25% ==> b
b
In some thread systems, a thread want be blocked until an other thread has exited. It can establish this goal by calling______ thread_create thread_exit thread_wait thread_yield
b
What is the purpose of process synchronization? Let different users run different processes independently Avoid race condition Avoid deadlock None of the other choices
b
Which conditions of mutual exclusion does the Lock Variables (Software proposal) violate? [A] No process must wait forever to enter its critical region [B] No two processes simultaneously in critical region [C] No process running outside its critical region may block another process [D] No assumptions made about speeds or numbers of CPUs
b
Which of the events that causes the processes to be created, when a running process creates one or more new process to help it to do its job? System initialization Execution of a process creation system call User request to create a new process Initiation of a batch job
b
Which of the following cannot be shared among different threads of a process? a. Process code b. File handles c. Process data d. Stack
b
Which of the following conditions that causes the processes to be terminated, when processes have done their work? [A] Fatal error (involuntary) [B] Normal exit (voluntary) [C] Killed by another process (involuntary) [D] Error exit (voluntary)
b
Which of the following process state transitions are illegal? a. Ready-> running b. waiting -> running c. running -> ready d. running -> terminated
b
Which of the following process state transitions are legal? a. waiting -> running b. running -> ready c. waiting -> terminated d. ready -> terminated
b
A computer has 2GB RAM of which the operating system occupies 1GB. The processes are all 450 MB and have the same characteristics. How many percent is CPU utilization when these programs are idle waiting for I/O 20% of the time? 4% 90% [C] None of the other choices (97,3%) [D] 96%
c
How many ways is Thread implemented? a. 1 b. 2 c. 3 d. None of the other choice
c
In a single processor system, mutual exclusion can be guaranteed by: (2314) a. Overlapping processes b. Interleaving processes c. Disabling interrupts d. All of the above
c
In a uniprocessor system, mutual exclusion can be guaranteed by: a. Overlapping processes b. Interleaving processes c. Disabling interrupts d. All of the above
c
OS Windows use system call_____, while OS Unix use system call______ to terminate processes normally exit; ExitProcess ExitProcess; exit ExitProcess; terminate terminate; ExitProcess
c
QN=11 (6925) What is the "sequential processes" concept? a. There are both many CPU and many PC b. All process is executed in concurrency c. No concurrency inside a process; everything happens sequentially d. None of the other choices
c
Which of the following conditions that causes the processes to be terminated, when the processes have a program bug? Normal exit (voluntary ) Error exit (voluntary) Fatal error (involuntary) Killed by another process (involuntary)
c
Which of the following process state transitions is correct, when the external event for which a process was waiting happens? Running -> Blocked (waiting) Running -> ready Blocked (waiting) -> ready Ready -> running
c
Which of the following process state transitions is correct, when the external event for which a process was waiting happens? a. Running -> Blocked (waiting) b. Running -> ready c. Blocked (waiting) -> ready d. Ready -> running
c
A entry of the Process table is called: [A] All of the other choices [B] Process check block [C] Process management block D process control block.
d
How many percent of the CPU time is wasted, when a computer system has enough room to hold two program and these programs are idle waiting for I/O 10% of the time? [A] 90% [B] 99% [C] None of the other choices [D] 1 % 10% time ==> 10% = x process = 2 = y %waste = x%^y ==> 10%^2 = 1% ==> D
d
Operating system abstraction supports the ability to have operation even when there is only one CPU available [A] None of the other choices [B] parallel [C] multiple [D] pseudoparallelism
d
Sometimes it happens that a thread wants to give another thread a chance to run. It can establish this goal by calling______ thread_create thread_exit thread_wait thread_yield
d
The following requirement must be met by any facility or capability that is to provide support for mutual exclusion: a. Only one process at a time can be allowed into a critical code section b. A process remains in its critical region for a finite time only c. No assumption can be made about relative process speeds d. All of the above
d
What is Software proposal in the solution of Mutual exclusion with Busy waiting a. Lock Variables b. Strict Alternation c. Peterson's Solution d. All of the above
d
Which of the following is appropriate to release page table and pages? a. Process creation b. Process execution c. Page fault time d. Process termination time
d
Which of the following process state transitions is correct, when the scheduler picks a process from the ready queue to run? Running -> Blocked (waiting) Running -> ready Blocked (waiting) -> ready Ready -> running
d
Which statement about disabling interrupts to resolve race conditions is wrong? In theory, a program can disable interrupts when it enters a critical section, and re-enable interrupts when finished with a critical section, to eliminate race conditions. Disabling/enabling interrupts may negatively affect the I/O system. Programs with infinite loops in their critical sections are a significant problem with the interrupt-based approach. User-mode programs are the best place to invoke disableInterrupt().
d
Which statement about disadvantage of Disabling interrupts, (the hardware solution to the critical region problem) is correct? If process is locked in Critical Section: System Halt Permit process to use command privileges: Danger! Don't ensure Mutual Exclusion for the system with N CPUs All of the other choices
d
mutual exclusion: a. Only one process at a time can be allowed into a critical code section b. A process remains in its critical region for a finite time only c. No assumption can be made about relative process speeds d. All of the above
d
