OSG key
A ____ is a portion of a process that can run independently A. thread B. program C. Mini-process D. subprocess
A
An arrival message causes the system to create a new thread to handle this message. This new thread is call______ A. Pop-up B. Upcall C. Activator D. Distributed
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 other choices
A
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
Operating system abstraction supports the ability to have ______ operation even when there is only one CPU available A. pseudoparallelism B. parallel C. multiple D. None of the other choices
A
Question #12 (1 point) Imagine that a certain printer can print 400 characters per second and that the time to write a character to the printer's output register is so short it can be ignored. If to run this printer using interrupt-driven I/O and each character printed requires an interrupt that takes 50 µsec all-in to service. How many percent of the CPU does the interrupt overhead cost? 2% of the CPU 98% of the CPU 4% of the CPU 96% of the CPU
A
Question #4 (1 point) An interrupt that leaves the machine in well-defined state is called a(n) ______ a, Precise interrupt b, Imprecise interrupt c, Required interrupt d, Disappointed interrupt
A
Question #9 (1 point) The I/O technique where the processor busy waits for an I/O operation to complete is called: Programmed I/O Interrupt-driven I/O Direct Memory Access (DMA) None of the other choices
A
Which of the following conditions must be held to provide good solution for mutual exclusion? 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 E. All of the other choices
A
Which of the following conditions that causes the processes to be terminated, when processes have done their work? A. Normal exit (voluntary ) B. Error exit (voluntary) C. Fatal error (involuntary) D. Killed by another process (involuntary)
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 entry of the Process table is called: A. Process management block B. Process control block C. Process check block D. All of the other choices
B
A process where no concurrency inside process; everything happens sequentially is called : A. Random access process B. Sequential process C. Sequential access process D. None of the other choices
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
B
What is the purpose of process synchronization? A. Let different users run different processes independently B. Avoid race condition C. Avoid deadlock D. None of the other choices
B
Which of the following conditions that causes the processes to be terminated, when the processes have a program bug? A. Normal exit (voluntary ) B. Error exit (voluntary) C. Fatal error (involuntary) D. Killed by another process (involuntary)
B
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? A. Running -> Blocked (waiting) B. Running -> ready C. Blocked (waiting) -> ready D. Ready -> running
B
In some thread systems, a thread want be blocked until an other thread has exited. It can establish this goal by calling______ A. thread_create B. thread_exit C. thread_wait D. thread_yield
D
Question #1 (1 point) Programmed I/O should be acceptable for which of the following systems? Interactive systems Multiprogramming systems Embedded systems None of the other choices
D
Question #11 (1 point) Which is the right order between the 4 I/O software layers? User-level I/O software, Device drivers, Interrupt handlers, Device-independent OS software User-level I/O software, Interrupt handlers, Device drivers, Device-independent OS software Device-independent OS software, user-level I/O software, Device drivers, Interrupt handlers User-level I/O software, Device-independent OS software, Device drivers, Interrupt handlers
D
Question #7 (1 point) Which approach is used in order to CPU communicate with the control registers of the I/O device? a, Separating I/O and memory space b, Memory-mapped I/O c, Hybrid: separating I/O and memory space and memory-mapped I/O d, All of the other choices
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 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 other choices
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 other choices
D
Which conditions of mutual exclusion does the Strict Alternation (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
D
Which of the following cannot be shared among different threads of a process? A. Process code B. File handles C. Process data D. Stack
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 external event for which a process was waiting happens? A. Running -> Blocked (waiting) B. Running -> ready C. Blocked (waiting) -> ready D. Ready -> running
D
Which of the following process state transitions is correct, when the scheduler picks a process from the ready queue to run? A. Running -> Blocked (waiting) B. Running -> ready C. Blocked (waiting) -> ready D. Ready -> running
D
Which statement about disabling interrupts to resolve race conditions is wrong? A. 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. B. Disabling/enabling interrupts may negatively affect the I/O system. C. Programs with infinite loops in their critical sections are a significant problem with the interrupt-based approach. D. 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? A. If process is locked in Critical Section: System Halt B. Permit process to use command privileges: Danger! C. Don't ensure Mutual Exclusion for the system with N CPUs D. All of the other choices
D
____ is the act of allowing only one process to have access to a dedicated resource A. No preemption B. Circular wait C. Resource holding D. Mutual exclusion
D
A computer with a 32-bit address uses a two-level page table. Virtual addresses are split into a 9-bit top-level page table field, an 11-bit second-level page table field, and an offset. How many pages are there in the address space? 2^20 pages 2^21 pages 2^22 pages 2^23 pages
a
A system with 32 bit virtual address. If the page size is 16 KB and each table entry occupies 4 bytes, what is the size of the page table? 1 MB 2 MB 4 MB 8 MB
a
Assume that process A-D make up the set of runnable processes on memory as B1 B2 B3 A1 A2 A5 A7 D3 D4 D6 C1 C6 C5. Suppose D gets a page fault. Which page is replaced using the local policy? Assume that the replaced page is always a last page. D6 B3 C5 None of the others
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
In "No Memory Abstraction", the static relocation technique is ____ a, When the program is loaded at address n, the constant n was added to every program address b, When the program is compiled, the address of program is added with the constant value where the program will be loaded c, After the program is loaded at address n, the constant n is stored at a particular register. d, None of the other choices
a
Question #3 (1 point) Which statement about DMA is incorrect? a, The controller does not need to wait for the CPU to transfer data to/from memory b, The CPU can start a DMA block transfer, and in the mean time do other work c, The CPU needs not to be concerned with the time it takes to transfer data d, It is always true that DMA is less expensive than CPU-mediate data transfers
a
The page table for each process maintains: The page frame location for each page of the process The page location for each frame of the process The physical memory location of the process None of the other choices
a
The second-chance page-replacement algorithm a, Moves pages found at the head of a FIFO queue with the referenced bit turned on back to the tail of the queue to avoid replacing them b, Searches through a circular list of pages and replaces the first page it encounters that has the referenced bit turned off c, Relies on a modified bit to determine which page to replace d, None of the other choices
a
There are ____ entries per page in the Page table. 1 2 3 4
a
Which of the events that causes the processes to be created, when an operation system is booted? A. System initialization B. Execution of a process creation system call C. User request to create a new process D. Initiation of a batch job
a
Which of the following information bits in the entry of page table is used to indicate Page Fault? Present/absent bit Status bit Referenced bit Modified bit
a
Which of the following is appropriate to determine program size and create page table? Process creation Process execution Page fault time Process termination time
a
Which of the following statements is incorrect about Translation Look-aside Buffer (TLB)? a, A TLB is sometimes known as an associative memory b, Each entry of a TLB contains the information about one page, including the virtual page number and the corresponding page frame c, A TLB miss implies a disk operation will follow d, None of the other choices
a
Which of these statements about the Inverted Page Table are true? a, An entry contains the pair (process, virtual page) mapped into the corresponding page frame b, An entry contains the pair (process, offset) mapped into the corresponding page frame b, An entry contains the pair (segment, virtual page) mapped into the corresponding page frame c, An entry contains the pair (segment, offset) mapped into the corresponding page frame
a
Which strategy is a simplest design for speeding up Paging? Page table is loaded into registers Page table is loaded into main memory Page table is loaded into disk Page table is loaded into TLB
a
Which of these statements about the algorithm "Next fit" is true? a, Memory Manager scans along the list of segments until it finds a hole that is big enough. b, Memory Manager starting searching the list of segments from the place where it left off last time. c, Memory Manager searches the entire list of segments from beginning to end and take smallest hole that is adequate. d, None of the other choices
b
Which solutions are used to solve the shared libraries? a, Relocation on the fly and position-independent code b, Position-independent code c, Static reallocation and position-independent code d, None of the other choices
b
With paging, when is the internal fragmentation possible? a, Page does not fit the frame b, The last page of the job is less than the maximum page size c, The virtual memory assigned to the program is less than the physical memory assigned to it d, Such thing cannot happen
b
Working set model is used for: a, Finding the minimum number of frames necessary for a job so that jobs can be run without "thrashing" b, Finding the average number of frames a job will need to run smoothly c, Determining whether page replacement is needed d, All of the other choices
b
____ gives users the appearance that their programs are being completely loaded in main memory during their entire processing time. Segmenting Virtual memory Shared memory Multithreading
b
Assume the Memory Manager receives a request for a block of 200. When the first-fit algorithm is used, ____ is the beginning address of the block granted by the Memory Manager. Beginning Address Memory Block Size 4075 105 5225 5 6785 600 7560 20 7600 205 10250 4050 a, 7600 b, 10250 c, 6785 d, 4075
c
Consider a swapping system in which the memory consists of the following hole sizes: 10K, 4K, 20K, 15K, 9K. Assume best fit algorithm is used. Which holes are taken for successive segment requests of 8K, 12K, 10K? 20K, 15K, 10K 10K, 15K, 20K 9K, 15K, 10K 10K, 20K, 15K
c
In terms of storage utilization the best method of Dynamic Storage Allocation is: a, Next fit b, First fit c, Best fit d, Worst fit
c
Page replacement algorithms determine a,When the system should update page table entries b,How many pages should be added to main memory c,Which pages should be brought into memory because a process is likely to reference them soon d,Which page to remove to provide space for an incoming page
c
Question #10 (1 point) In the memory-mapped I/O system, in order that CPU communicates with the control registers in the devices, the control register is assigned : a, Index b, I/O address c, Unique memory address d, None of the other choices
c
Question #2 (1 point) Which mechanism is described as "the device controller sneaks in and steals an occasional bus cycle from the CPU once in a while, delaying it slightly"? a, Interrupt stealing b, Cycle sneaking c, Cycle stealing d, All of the others
c
Question #8 (1 point) Which of the following statements is not correct about DMA? a, DMA controller has access to the system bus independent of the CPU b, DMA helps reduce the number of interrupts (in comparison with interrupt-driven I/O) c, DMA controller is usually faster than CPU d, The operating system can only use DMA if the hardware has a DMA controller
c
Suppose a virtual address space of 2^24 words and the page size is 2^12 words. If the virtual address is 123456 in Hexadecimal, what would be the page number in Hexadecimal? 123 1234 12345 123456
c
The ____ policy is based on the theory that the best page to remove is the one that has been in memory the longest NRU LRU FIFO LIFO
c
The actual location in main memory is called a(n): a, Relative address b, Logical address c, Absolute address d, None of the other choices
c
The methods determine where page is on the disk when it is paged out is a, Paging to a static swap area b, Backing up pages dynamically c, Both Paging to a static swap area and Backing up pages dynamically d, None of the other choices
c
The modified/dirty bit is used for the purpose of: a, Implementing FIFO page replacement algorithm b, Dynamic allocation of memory used by one process to another c, Reduce the average time required to service page faults d, None of the other choices
c
The task of subdividing memory between the OS and processes is performed automatically by the OS and is called: a, Protection b, Relocation c, Memory Management d, All of the other choices
c
When there is an excessive amount of page swapping between main memory and secondary storage, the operation becomes inefficient, which is called ____. excessive demand paging hot swapping thrashing Over swapping
c
Which is not true about the method of backing store: "Paging to a static swap area"? a, The swap area on the disk is as large as the process virtual address space b, Calculating the address in swap area requires knowing only where the process' paging area begins c, Requires a disk map in memory d, A page that is in memory always have shadow copy on disk
c
Which of following is true about disk storage in the memory hierarchy? Small amount of fast expensive memory Some medium-speed medium price Gigabytes of slow cheap memory None of the other choices
c
Which of the following information bits in the entry of page table is used to indicate what kinds of access are permitted? Present/absent bit Caching disabled Protection bit Modified bit
c
Which of the following is a method to keep track of memory usages? a, Memory Management with Bit Maps b, Memory Management with Linked Lists c, Both Memory Management with Bit Maps and Memory Management with Linked Lists d, None of the other choices
c
Which of these statements about the algorithm "Best fit" is true? a, Memory Manager scans along the list of segments until it finds a hole that is big enough. b, Memory Manager starting searching the list of segments from the place where it left off last time. c, Memory Manager searches the entire list of segments from beginning to end and take smallest hole that is adequate. d, None of the other choices
c
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 of the CPU time is wasted, when these programs are idle waiting for I/O 20% of the time? A. 90% B. 96% C. 4% D. None of the other choices
d
A page fault means that we referenced a page That was outside the memory boundaries With an incorrect I/O request That was not in secondary storage That was not in main memory
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
If there are 64 pages and the page size is 2048 words, what is the length of logical address? 14 bits 15 bits 16 bits 17 bits
d
One of the most important innovations of demand paging was that it made ____ feasible Memory demand Virtual demand Virtual paging Virtual memory.
d
Question #6 (1 point) Which of the following statements about device drivers is correct? a, Device drivers lie on top of I/O software layer architecture b, Device drivers lie on bottom of I/O software layer architecture c, Device drivers layer lies right above the interrupt handlers layer and below the device-independent OS software layer d, None of the other choices
d
Which is not true about "Backing up pages dynamically"? a, Pages do not have fixed swap area on the disk b, Requires a disk map in memory c, When a page is swapped out, an empty disk page is chosen on the fly and disk map is updated accordingly d, Needs less main memory than the method "Paging to a static swap area"
d
Which of following statements about the memory hierarchy is false? Small amount of fast expensive memory - cache Some medium-speed medium price main memory Gigabytes of slow cheap disk storage None of the other choices
d
Which of the events that causes the processes to be created, when the operation system creates a new process and runs the next job from the input queue? A. System initialization B. Execution of a process creation system call C. User request to create a new process D. Initiation of a batch job
d
Which of the following process state transitions is illegal? A. Running -> Blocked (waiting) B. Running -> ready C. Blocked (waiting) -> ready D. Ready -> Blocked (waiting)
d
Which of these statements about the algorithm "Worst fit" is true? a, Memory Manager scans along the list of segments until it finds a hole that is big enough. b, Memory Manager starting searching the list of segments from the place where it left off last time. c, Memory Manager searches the entire list of segments from beginning to end and take smallest hole that is adequate. d, None of the other choices
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 SJF (Shortest job first) scheduling. Ignore process switching overhead. 14 minutes 8 minutes 6 minutes 18.8 minutes
b
In a system employing a paging scheme for memory management, wasted space is due to: External fragmentation Internal fragmentation Pages and frames of different specified sizes None of the other choices
b
In terms of speed the best method of Dynamic Storage-Allocation is: Next fit First fit Best fit Worst fit
b
LRU replaces the page that has spent the a, longest time in memory b, longest time in memory without being referenced c, shortest time in memory d, shortest time in memory without being referenced
b
The page size that is too small will generate ____ a, Excessive internal fragmentation b, Very long Page tables c, More difficult to calculate actual position d, Excessive external fragmentation
b
What is not the technique of implementation for Virtual Memory? a, Segmentation b, Partition c, Paging d, All of the other choices
b
When a virtual memory system manages memory in fixed length units, which of the following terms correctly represents its unit? Frame Page Block Segment
b
Which of following is true about main memory in the memory hierarchy? Small amount of fast expensive memory Some medium-speed medium price Gigabytes of slow cheap memory None of the other choices
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? A. System initialization B. Execution of a process creation system call C. User request to create a new process D. Initiation of a batch job
b
How many percent of the CPU time is wasted, when a computer system has enough room to hold two programs and these programs are idle waiting for I/O 10% of the time? A. 90% B. 99% C. 1% D. None of the other choices
C
How many ways is Thread implemented? A. 1 B. 2 C. 3 D. None of the other choices
C
In a single processor system, mutual exclusion can be guaranteed by: A. Overlapping processes B. Interleaving processes C. Disabling interrupts D. All of the other choices
C
OS Windows use system call_____, while OS Unix use system call______ to terminate processes normally A. exit; ExitProcess B. ExitProcess; exit C. ExitProcess; terminate D. terminate; ExitProcess
C
Question #5 (1 point) In general, which is the best technique for I/O Data transfer? a, Programmed I/O b, Interrupt-Driven I/O c, Direct Memory Access d, None of the other choices
C
Sometimes it happens that a thread wants to give another thread a chance to run. It can establish this goal by calling______ A. thread_create B. thread_exit C. thread_wait D. thread_yield
C
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 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
C
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? A. Normal exit (voluntary ) B. Error exit (voluntary) C. Fatal error (involuntary) D. Killed by another process (involuntary)
C
