OSG202

An Operating System is? a. A program that acts as an intermediary between computer processor and computer memory b. A program that acts as an intermediary between a user of a computer and a user of another computer c. A program that acts as an intermediary between computer software and computer hardware d. A program that acts as an intermediary between a user of a computer and the computer hardware

d

An example of the key differences that can exist across (and even in) classes of I/O devices is: a. Data rate b. Data representation c. Error conditions d. All of the above

d

Assume the following events and actions take place. The following statement____ is true. Event Action 1 P1 requests and is allocated R1. 2 P2 requests and is allocated R2. 3 P3 requests and is allocated R3. 4 P1 requests R2. 5 P2 requests R3. 6 P3 requests R1. a. There is no deadlock b. Event 4 caused deadlock c. Event 5 caused deadlock. d. Event 6 caused deadlock.

d

Booting a contemporary general purpose computer involves the following steps, except a. Execution of a ROM-based POST sequence b. Loading one or more bootstrap loaders c. Loading the OS d. Starting the command interpreter

d

Booting a general purpose computer involves the following steps except a. Execution of a ROM-based POST sequence b. Loading one or more bootstrap loaders c. Loading the OS d. Loading the command interpreter

d

DMA operations require the following information from the processor a. Address of I/O device b. Starting memory location to read from and write to c. Number of words to be read or written d. All of the other choices

d

Dijkstra's Banker's Algorithm require the system to maintain the resource information for each process, including: a. A count of the system's total resources b. The maximum resources that can be requested by the process c. The number of resources currently acquired by the process d. B and C

d

File Structure can be: a. Byte sequence b. Record sequence c. Tree d. All of the other choices

d

Which is the least common reason that a running thread might cease using the CPU? a. Thread completes execution b. Thread requests resource, and blocks c. Thread voluntarily releases CPU d. Thread involuntarily releases CPU

d

What is not correct about system calls? a. A system call allows a user process to assess and execute operating system functions inside the kernel. b. User programs use system calls to invoke operating system services c. In terms of performance, using system calls is better than using procedure calls d. Every system call involves overhead due to context switch

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

What is the main characteristic of real-time operating system? a. Multiple CPU b. Time-sharing c. Time is key parameter d. Many I/O devices

c

What is the value of mode bit in User Mode? a. 00 b. 11 c. 1 d. 0

c

What is the weakness of the Banker's algorithm? a. Allowing the population of processes to vary over time b. Enabling processes to hold their resources indefinitely c. Requiring that processes state their maximum needs in advance d. Enabling the number of resources to fluctuate

c

When there is an excessive amount of page swapping between main memory and secondary storage, the operation becomes inefficient, which is called ____. a. excessive demand paging b. hot swapping c. thrashing d. Over swapping

c

Which command is used to display the absolute pathname for the directory that you are working in? a. dir b. whereami c. pwd d. ls

c

Which command is used to jump on sub-directory? a. jump b. cd c. change -n d. move

c

Which deadlock condition does "Take resources away" attack? a. Mutual exclusion b. Hold and wait c. No preemption d. Circular-wait condition

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 is the voluntary-condition which terminated process? a. Job error b. Killed by another process c. Error exit d. Killed by user

c

Which of special register contains the Mode Bit (user or kernel)? a. Instruction Register (IR) b. Program Counter (PC) c. Program Status Word (PSW) d. None of the other choices

c

Which of the following allocation methods the i-nodes use? a. Contiguous allocation b. Linked allocation c. Indexed allocation d. Linked allocation using FAT

c

Which of the following information bits used by the various page replacement policies indicates if the page has been called lately? a. Locality bit b. Status bit c. Referenced bit d. 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 the following is a preemptive scheduling algorithm a. FCFS b. Shortest Job First c. Round Robin d. None of the above

c

Which of the following is correct about symbolic links? a. Symbolic links need not space to store the path name b. Symbolic links can only point to files on the same machines c. Symbolic links can point to files in the network d. None of the other choices

c

Which of the following is correct about the advantages of layered system? a. Easier to extend b. Easier to debug from lower to upper layer c. Easier to extend and Easier to debug from lower to upper layer d. None of the other choices

c

A trap instruction doesn't cause this CPU hardware step to occur: a. Switch the CPU to supervisor mode b. Consult the trap table c. Load the PC with an address found in the trap table d. Return control to the user code which invoked the trap instruction

d

What is the correct statement about the process of booting a computer? a. BIOS loads the operating system immediately into RAM b. BIOS detects the boot device, the boot sector determines the active partition, then the boot loader loads the operating system c. None of the above

b

What is the main difference function between Operating Systems for Mainframe computer and Personal computer? a. Multitask b. Many I/O devices c. Multi-user d. Multiprogramming

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

What is true about preemptable resources? a. Will cause the process to fail if taken away b. Can be taken away from a process with no ill effects c. Can share among processes d. None of the other choices

b

What kind of I/O devices that disks and tapes belong to? a. Stream-oriented devices b. Block-oriented devices c. Character-oriented devices d. None of the above

b

What part of the boot process determines whether the peripheral devices are working properly? a. CMOS b. POST c. ROM d. BIOS

b

When a virtual memory system manages memory in fixed length units, which of the following terms correctly represents its unit? a. Frame b. Page c. Block d. Segment

b

Which cannot be able to solve the race condition? a. TSL b. Shared memory c. Semaphore d. Monitor

b

Which class of I/O devices that disks and tapes belong to? a. Stream devices b. Block devices c. Character devices d. None of the other choices

b

Which command can be used to list all file (include hidden files) inside current directory? a. ls * b. ls -a c. ls -l d. show -a

b

Which command will display current day? a. day b. date c. view date d. calendar

b

Which deadlock condition does "Request all resources initially" attack? a. Mutual exclusion b. Hold and wait c. No preemption d. Circular-wait condition

b

Which of main bus in the IBM PC computer, that can run at 66 MHz and transfer 8 bytes at a time? a. ISA (Industry Standard Architecture) b. PCI (Peripheral Component Interconnect) c. ISA and PCI d. None of the other choices

b

Which of the following I/O software do Device drivers do? a. Converting binary integers to ASCII for printing b. Writing commands to the device registers c. Checking to see if the user is permitted to use the device d. None of the other choices

b

Which of the following actions generates an external interrupt? a. A page that does not exist in the main memory is accessed by the virtual storage management. b. An input/output operation is completed. c. Division by zero occurs. d. A system call instruction is executed.

b

Which of the following instructions should be allowed in user mode? a. Disable all interrupts b. Read the time-of-day clock c. Set the time-of-day clock d. Change the memory map

b

~ A system with 32 bit virtual address. If the page size is 16KB words and each table entry occupies 4 bytes, what is the size of the page table?

1 MB

The following statements about AND synchronization are true except a. Simultaneous semaphore is a programming convenience b. Simultaneous semaphore is an abstraction of a basic semaphore c. Simultaneous semaphore is slightly more powerful than basic semaphore d. Simultaneous semaphore uses basic semaphore in a particular pattern

c

The four main structural elements of a computer system are: a. Processor, Registers, I/O Modules, Main Memory b. Processor, Registers, Main Memory, System Bus c. Processor, Main Memory, I/O Modules, System Bus d. None of the other choices

c

The i-nodes are used in which of the following allocation methods a. Contiguous allocation b. Linked allocation c. Indexed allocation d. Linked allocation using FAT

c

The operating system does each of the following except a. Allocates the computer's components to different programs b. Synchronizes individual programs' activities c. Ensures that programs terminate their execution d. Provides the general mechanisms that are needed so that the programs execute in perfect harmony

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 above

c

Typical approaches to handle deadlocks do not include a. Prevention b. Detection c. Deterrence d. Avoidance

c

What following resource allocation state is unsafe? a. Fig. B b. Fig. C c. Fig. B and Fig. C d. None of the other choices

c

If I-node contains 10 direct addresses of 4 byte and all disk blocks are 1024KB, what is largest possible file a. 10 MB b. 10 GB c. 1 GB d. None of the choice is correct

a

If in a resource-allocation graph, each resource type has exactly one instance, which of the following indicate a deadlock situation? a. The graph has at least one cycle. b. The graph has no cycle. c. The graph is connected. d. The graph is not connected.

a

What is incorrect about contiguous allocation of files ? a. It is simple to implement b. It leads to excellent read performance c. It does not cause disk fragmentation d. It is widely used on CD-ROMs

c

What is interrupt vector? a. A signal an I/O device sends to CPU b. A signal an I/O device sends to CPU c. Part of memory which contains the addresses of interrupt handlers d. None of the above

c

What is not a main function of an operating system? a. Provide the users with an extended (virtual) machine b. Manage the I/O devices c. Provide user interfaces d. Support virtual memory

c

The term multiprogramming means a. Running programs on multiple machines b. Switching the CPU between executing programs in order to maximize resource utilization c. Allowing multiple users to write programs simultaneously d. None of the other choices

b

What is the characteristic of deadlocked systems a. Starvation b. Circular wait c. Saturation d. Aging

b

What is the correct approach with the Hold and Wait condition to prevent Deadlock? a. Spool everything b. Request all resources initially c. Take resources away d. Order resources numerically

b

~ A common class of interrupt is

I/O

A computer uses a programmable clock in square-wave mode. If 500 MHz crystal is used, what should be the value of the holding register to achieve a clock resolution of 1 msec (Clock tick)? a. 500,000 b. 50,000 c. 5,000,000 d. 50,000,000

a

A major distinction between events and semaphores is that if no thread is waiting when a signal is raised, the result of the signal() operation is not save and its occurrence will have no effect a. true b. false

a

A monitor forces a process to wait if another process is currently executing one of the monitor's member functions a. true b. false

a

A(n) _________ is provided to make system calls from some programming languages a. procedure library b. operator c. pointer d. None of the other choices

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

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

Choose the correct statement about safe and unsafe states a. To avoidance deadlocks → ensure that a system will never enter an unsafe state b. If a system is in safe state → possibility of deadlock c. If a system is in unsafe state → no deadlocks d. All of the others

a

Consider a swapping system in which memory consists of the following hole sizes in memory order: 10 KB, 4 KB, 20 KB, 18KB, 7 KB, 9KB, 12 KB, and 15 KB. Which hole is take for successive segment requests of 12 KB, 10KB, 9KB for first fit? a. 20 KB, 10 KB, 18 KB b. 12KB, 10 KB, 9KB c. 20KB, 18KB, 15 KB d. 20KB, 18KB, 9KB

a

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

Device Driver is normally written by: a. Device's Manufacturer b. OS's Manufacturer c. Computer's Manufacturer d. All of the above

a

Files are distinguished from other resources except that a. The interface is exceptionally complex as compared with most other resources. b. They are the prevalent form of storing information c. Operating systems often use the file as a primitive for modeling other resource abstractions d. UNIX pipes can be modeled as files

a

How much cylinder skew is needed for a 7200- RPM (rotate per minute) disk with the track-to-track seek time of 1 msec? The disk has 200 sectors of 512 bytes on each track. a. 24 sectors b. 12 sectors c. 36 sectors d. 18 sectors

a

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? a. 2% of the CPU b. 98% of the CPU c. 4% of the CPU d. 96% of the CPU

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

MS-DOS is a example of .... a. Monolithic system b. Layered System c. Virtual Machine d. Client-server model

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

Of the three components of access time in a disk, ____ is the longest. a. Seek time b. Search time c. Transfer time d. Delay time

a

Personal desktop computers use a________ operating system. a. single-user, multitask b. single-user, single-task c. multiuser d. real-time

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: a. Binary semaphores b. Integer semaphores c. Counter semaphores d. None of the other choices

a

The I/O technique where the processor busy waits for an I/O operation to complete is called: a. Programmed I/O b. Interrupt-driven I/O c. Direct Memory Access (DMA) d. None of the above

a

The aspect of disk performance that represents the time it take to position the head a desired track is known as a. Rotational delay b. Access time c. Seek time d. None of the other choices

a

The critical section problem is a special case of the mutual exclusion problem a. true b. false

a

The page table for each process maintains: a. The frame location for each page of the process b. The page location for each frame of the process c. The physical memory location of the process d. None of the above

a

The process is the computational environment that includes each of the following except a. Operating system b. Data c. Program d. Files

a

The process manager commonly interacts with other components except a. Device controller b. Device manager c. Memory manager d. File manager

a

The scheme of ____ removes the possibility of a circular wait and therefore guarantees the removal of deadlocks. a. Hierarchical ordering b. Preemption c. Saving and restoring job state d. Requesting all resources before job run

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 above

a

The simplest way to break a deadlock is to a. Kill one of the processes b. Roll back c. Preempt a resource d. Lock one of the processes

a

The system is said to be in an unsafe state if a. The operating system cannot guarantee that all current processes can complete their work b. The system is deadlocked c. A process is indefinitely postponed d. None of the above

a

The two basic types of processor registers are: a. General and special registers b. Control and Status registers c. User-visible and user-invisible registers d. None of the above

a

What is a "stripping" in RAID? a. Distributing data over multiple drives b. Take away possessions from someone c. Get undressed d. All of the other choices

a

What is the correct approach with the Mutual Exclusion condition to prevent Deadlock? a. Spool everything b. Request all resources initially c. Take resources away d. Order resources numerically

a

What is the purpose of CPU scheduling algorithms? a. Pick one of the ready processes to run next b. Put to sleep and wake up processes in an efficient manner c. Allocate memory to the processes in a fair and efficient way d. None of the other choices

a

What is the table where its entry contains the memory address of Interrupt service routine a. Interrupt vector table b. Interrupt table c. Address table d. Address lines table

a

When an external device becomes ready to be serviced by the processor, the device sends this signal to the processor a. Interrupt signal b. Halt signal c. Handler signal d. None of the abovee

a

Which RAID level duplicates all the disks? a. 1 b. 2 c. 3 d. 4

a

Which command would you use to create a sub-directory in your home directory? a. mkdir b. dir c. cp d. rm

a

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 is not a characteristic of a thread? a. Thread identifier b. Thread parent identifier c. Thread-specific data d. Process environment

a

A possibility of deadlock can occur: a. If a system is in safe state b. If a system is in unsafe state c. If a system is in instable state d. None of the other choices

b

Which is the correct description of transitions between process states below? (see picture) a. 1: Process blocks for input; 2: Scheduler picks another process; 3: Scheduler picks this process; 4: Input becomes available b. 1: Process blocks for input; 2: Scheduler picks this process; 3: Scheduler picks another process; 4: Input becomes available c. 1: Process blocks for input; 2: Input becomes available; 3: Scheduler picks another process; 4: Scheduler picks this process d. 1: Process blocks for input; 2: Input becomes available; 3: Scheduler picks this process; 4: Scheduler picks another process

a

Which is the maximum partition size, if the FAT type is FAT-32 and the block size is 4 KB? a. 1 TB b. 128 MB c. 256 MB d. 512 MB

a

Which mechanism is implemented by writing to the log file with the purpose of file system management and optimization? a. Journaling File Systems b. Log-Structured File Systems c. Virtual File Systems d. None of the other choices

a

Which of following is true about cache in the memory hierarchy? a. Small amount of fast expensive memory b. Some medium-speed medium price c. Gigabytes of slow cheap memory d. None of the other choices

a

Which of the following information bits in the entry of page table is used to indicate Page Fault? a. Present/absent bit b. Status bit c. Referenced bit d. Modified bit

a

Which of the following is an operating system component? a. Process Management b. Speed Management c. Space Management d. Time Management

a

Which of the following is appropriate to determine program size and create page table? a. Process creation b. Process execution c. Page fault time d. Process termination time

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

Which of the following statements is true about hardware solution to the critical region problem? a. Disable Interrupts b. Monitors c. Semaphore 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 c. An entry contains the pair (segment, virtual page) mapped into the corresponding page frame d. An entry contains the pair (segment, offset) mapped into the corresponding page frame

a

Which statement about monitors is incorrect? a. Monitors can solve just a proper subset of synchronization problems solvable with semaphores b. Monitors provide a simplified paradigm for some synchronization problems c. Monitors can solve synchronization problems too complex for semaphores d. Monitors are based on abstract data types

a

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

a

____ is a specialized WRITE command for existing data files that allows for adding records to end of the file. a. APPEND b. UPDATE c. REWRITE d. MODIFY

a

A multiprogramming OS allows more than one process at a time to be loaded into the primary memory, but limits processes to one thread each a. true b. false

b

A CPU may have multiple execution units, so that can carry out multiple instructions in the same time is called: a. Pipeline b. Superscalar(siêu vô hướng) c. Multicore d. None of the other choices

b

A Control/Status register that contains the address of the next instruction to be fetched is called the: a. Instruction Register (IR) b. Program Counter (PC) c. Program Status Word (PSW) d. All of the above

b

A fetched instruction is normally loaded into a. Instruction Register (IR) b. Program Counter (PC) c. Accumulator (AC) d. None of the above

b

A system has four processes and five allocated resources. The current allocation and maximum needs are as follows: Process Allocated Maximum Available ------------------------------------------------------------------------------------------------------------------ A 10211 11212 00x11 B 20110 22210 C 11011 21311 D 11010 11121 What is the smallest value of x for which this is a safe state? a. 0 b. 1 c. 2 d. 3

b

A well-known Embedded operating system is: a. TinyOS b. QNX and VxWork c. Symbian OS and Palm OS d. e-COS

b

All deadlocks involve conflicting needs for resources by a. One or more processes b. Two or more processes c. Three or more processes d. None of the above

b

Assume the Memory Manager receives a request for a block of 200. When the worst-fit algorithm is used, ____ is the beginning address of the block granted by the Memory Manager. 4075 105 5225 5 6785 600 7560 20 7600 205 10250 4050 a. 7600 b. 10250 c. 6785 d. 4075

b

Basic process states include the following except a. blocked b. done c. running d. ready

b

Consider a swapping system in which the memory consists of the following hole sizes: 10 K, 4 K, 20 K, 15 K, 9 K. Assume first fit algorithm is used. Which holes are taken for successive segment requests of 8 K, 12 K, 10 K? a. 9 K, 15 K, 10 K b. 10 K, 20 K, 15 K c. 20 K, 15 K, 4 K d. None of the other choices

b

Consider an i-node which contains 8 direct addresses of 4 bytes each and all disk blocks are 1 KB. Also consider that the i-node contains an additional "single indirect address" that is used for containing more disk block addresses. What is the largest possible file? a. 262 KB b. 264 KB c. 266 KB d. 268 KB

b

Device drivers implement the device independent aspects of device management a. true b. false

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. a. 14 minutes b. 8 minutes c. 6 minutes d. 18.8 minutes

b

Given an operating system performing file management using a directory with a hierarchical structure, which of the following is specified to indicate the directory where the file is located? a. Extension b. Path c. Root directory d. Sub-directory

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

In a system employing a paging scheme for memory management, wasted space is due to: a. External fragmentation b. Internal fragmentation c. Pages and frames of different specified sizes d. None of the above

b

In terms of main memory efficiency the method of "Backing up pages dynamically" in comparison with the method of "Paging to a static swap area" is a. Better b. Worse c. Equal d. Nearly equal

b

In terms of speed the best method of Dynamic Storage-Allocation is: a. Next fit b. First fit c. Best fit d. Worst fit

b

In the synchronization context, process creation and destruction tend to be quite costly operations because of the following, except a. Creation/destruction require considerable manipulation of process descriptors b. Parent processes have difficulty tracking concurrent creation and destruction of child processes c. Protection mechanism are extensively executed d. Memory management is heavily invoked

b

Information that must be saved prior to the processor transferring control to the interrupt handler routine includes: a. PSW b. PSW and PC c. PSW and Contents of processor registers d. None of the other choices

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

Memory is usually word-addressable, to match the CPU word size a. true b. false

b

New synchronization methods such as AND, Events, and Monitors enable solutions to problems that cannot be solved solely with semaphores a. true b. false

b

Placing mailboxes in user space is preferable to placing them in system space a. true b. false

b

Programmers need to know device details in order to use a device a. true b. false

b

Random Access memory: a. Is typically faster than cache memory b. Is volatile c. Can only be read sequentially d. Stores all the files on the computer

b

Semaphores are only useful for solving critical section problems, and not other synchronization problems a. true b. false

b

The File Manager writes the volume name and other descriptive information on an easy-to-access place on each unit: ____ of the CD or DVD a. The outermost part b. The innermost part c. Immediately following the master file directory d. Stored at the beginning of the volume

b

The OS implementation of a scheduler normally does not include a. Context switcher code b. Procedure call handler code c. System call handler code d. Interrupt handler code

b

The first-come, first-served (FCFS) algorithm is fine for most ____ systems a. Interactive b. Batch c. Real time d. Multiuser

b

The general role of an operating system is to: a. Act as an interface between various computers b. Provide a set of services to system users c. Manage files for application programs d. None of the above

b

The permanent blocking of a set of processes that compete for system resources is called a. Starvation b. Deadlock c. Prioritization d. None of the other choices

b

The scheduling strategy where each process in the queue is given a certain amount of time, in turn, to execute and then returned to the queue, unless blocked is referred to as: a. Prioritization b. Round-Robin c. LIFO d. All of the above

b

Which of the following is NOT a correct explanation of UNIX which is one of the OS? a. Provides network functions that easily implement distributed processing. b. It is a single- user and multi-task OS c. Since its specifications have been released to the public and it has a high portability, it has been adopted in a wide range of devices. d. Provides an interactive human interface that uses character- based commands.

b

Which of the following is not correct about the reliability of different RAID levels? 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

b

Which of the following is specified to indicate the directory where the file is located? a. Extension b. Path name c. Root directory d. Sub-directory

b

Which of the following is true about the block size in disk space management a. The larger the block size is the lower the data rate is b. The larger the block size is the worse the disk space utilization is c. The larger the block size is lesser the disk space is d. None of the other choices

b

Which of the following is true about the block size in disk space management a. the larger the block size is the lower the data rate is b. the larger the block size is the worse the disk space utilization is c. the larger the block size is lesser the disk space is d. none of the above

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

Which of the following statements about Random Access memory (RAM) is correct? a. Is typically faster than cache memory b. Is volatile c. Can only be read sequentially d. Stores all the files on the computer

b

Which of the following statements does not apply to manual deadlock management? a. Deadlock is relatively infrequent for some system resources b. OS designers are normally very sensitive to deadlock when designing resource managers c. Recovery may involves rebooting the system d. None of the other choices

b

Which of the following statements is correct about Shortest Job First a. Avoid Starvation b. Minimize average waiting time c. Both a and b d. None of the above

b

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 part of a disk is used to boot the computer? a. Boot Block b. MBR (Master Boot Record) c. Root Block d. Super Block

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

____ is when each process involved in the impasse is waiting for another to voluntarily release the resource so that at least one will be able to continue on. a. Mutual-exclusion condition b. Circular-wait condition c. Hold and wait condition d. No preemption condition

b

b Which of the following is used in mutual exclusion (exclusive control)? a. Checkpoint b. Contention c. Hash d. Semaphore

b

A UNIX process contains each of the following except a. Text segment b. Data segment c. Thread segment d. Stack segment

c

A ____ is a group of related records that contains information to be used by specific application programs to generate reports. a. Field b. Record group c. File d. Directory

c

A computer with a 32-bit address uses a two-level page table. Virtual addresses are split into a 10-bit top-level page table field, an 12-bit second-level page table field, and an offset. How large are the pages? a. 4-KB page b. 2-KB page c. 1-KB page d. 512B page

c

A file is generally defined to be: a. A basic element of data b. A collection of related fields c. A collection of similar records d. All of the above

c

A system with 32 bit virtual address. If the page size is 4 KB and each table entry occupies 4 bytes, what is the size of the page table? a. 1 MB b. 2 MB c. 4 MB d. 8 MB

c

A time-sharing system is a. Another name for a batch system b. A multi-user, multi-process, interactive system c. All of the above d. None of the above

c

As one proceeds down the memory hierarchy (phân cấp bậc nhất) (from inboard memory to offline storage), which of the following conditions is correct? a. Increasing cost per bit b. Decreasing capacity c. Increasing access time(thời gian truy xuất tăng) d. None of the other choices

c

Assume jobs A-D arrive at almost the same time in the READY queue. Determine the average turnaround time for SJF scheduling. Ignore process switching overhead a. 5.5 b. 6.8 c. 9.0 d. 11.1

c

Assume jobs A-D arrive in quick succession in the READY queue. Using round robin scheduling (quantum=4), the turnaround time for job D is ____. Arrival time: 0 1 2 3 Job: A B C D CPU cycle: 8 4 9 5 a. 7 b. 20 c. 22 d. 24

c

Disk can be divided up into one or more partitions. The first block of every partition is called: a. Free block b. MBR c. Boot block d. Super block

c

Each device attached to your computer comes with a special program called a __________ that facilitates the communication between the device and the OS. a. device configurator b. translator c. device driver d. communication utility

c

How many context switches occur whenever application processes are multiplexed? a. 1 b. 2 c. 4 d. 8

c

How many percent is CPU utilization, 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

c

How many ways is Thread implemented? a. 1 b. 2 c. 3 d. None of the other choice

c

In a fixed magnetic disk, each circle is called a ____. a. sector b. block c. track d. platter

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 above

c

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 above

c

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

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

On a magnetic disk, which is not a critical timing characteristic? a. Rotational latency b. Track seek time c. Sector header erasure time d. Data transfer latency

c

Some systems increase the priority of jobs that have been in the system for an unusually long time to expedite their exit, which is known as ____.? a. Lagging b. Bumping c. Aging d. Accelerated priority

c

Suppose a virtual address space of 2^32 words and the page size is 2^12 words. If the virtual address is 12345678 in Hexadecimal, what would be the page number in Hexadecimal? a. 123 b. 1234 c. 12345 d. 123456

c

The Linking technique that allows the file to appear in more than one directory are: a. Hard link b. Symbolic link c. Both hard link and symbolic link d. Soft link

c

The ____ policy is based on the theory that the best page to remove is the one that has been in memory the longest a. NRU b. LRU c. FIFO d. LIFO

c

The _____ command will list all working processes? a. ls b. jobs c. ps d. pwd

c

The absolute pathname of a file in Linux with respect to the a. Home directory b. Login directory c. Root directory on the system d. All of the others

c

The actual location in main memory is called a(n): a. Relative address b. Logical address c. Absolute address d. None of the above

c

Which of the following is not correct about user-level threads ? a. User-level threads are more efficient than kernel threads, in the sense that they do not need kernel calls to switch among threads b. User-level threads cannot be preempted by clock interrupts unless the whole process' quantum has been used up c. With user-level threads, customized scheduling algorithms cannot be implemented d. If one user-level thread makes a blocking system call, the system will block the entire process (which contains that user-level thread)

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

Which of the following process state transitions is illegal? a. Running -> Blocked (waiting) b. Running -> ready c. Blocked (waiting) -> ready d. Ready -> Blocked (waiting)

c

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

c

Which of the following statements is incorrect about the CMOS? a. Is volatile b. To hold the current time and date c. To contain BIOS d. To hold the configuration parameters

c

Which of the following statements is incorrect? a. The term data rate refers to the speed with which data moves to and from the individual I/O device b. In the interrupt-driven I/O technique, the processor issues an I/O request, continues with other work and eventually receives notification that the request was fulfilled c. A hard drive is an example of a character-oriented I/O device d. None of the above

c

Which of the following statements is not correct about "device independence"? a. Files and devices are accessed in the same way, independent of their physical nature b. A system has to maintain only one set of system calls for both writing on a file and writing on the console c. Device independence requires all programmers to deal with different devices directly d. Device independent interfaces should be given to programmers

c

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

Which statement about IPC is incorrect? a. The OS explicitly copies information from a sending process's address space into a distinct receiving process's space b. Sometimes, the OS can perform the copy by overriding the memory security mechanism c. If the sender and receiver are on different machines, the OS must obtain additional cooperation of the two processes d. IPC is rarely used between threads in a single process

c

Which statement about test-and-set is incorrect? a. It is the dominant way to accomplish semaphores in modern hardware b. Test-and-set involves both a memory location and a register c. Test-and-set executes as a sequence of machine instructions d. Test-and-set can make semaphore implementation simple and efficient

c

Which strategy is used in the Banker's algorithm for dealing with deadlocks? a. Deadlock Ignorance b. Deadlock Detection c. Deadlock Avoidance d. Deadlock Prevention

c

_____ is the command that writes the bottom 10 lines of a file to the screen. a. pr b. split c. tail d. head

c

A operation concerning Stable Storage is: a. Stable writes b. Stable Reads c. Crash recovery d. All of the other choices

d

A page fault means that we referenced a page a. that was outside the memory boundaries b. with an incorrect I/O request c. that was not in secondary storage d. that was not in main memory

d

A simple structuring model for monolithic system includes: a. A main program that invokes the requested service procedure b. A set of service procedures that carry out the system calls c. A set of utility procedures that help the service procedures d. All 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. Their (externally determined) priorities are 3, 5, 2, 1, and 4, respectively, with 5 being the highest priority. Determine the average turnaround time for priority scheduling. Ignore process switching overhead. Job: A B C D CPU cycle: 5 2 6 4 a. 6 minutes b. 12.8 minutes c. 18.8 minutes d. 16.8 minutes

d

If a deadlocked system, the processes can a. run b. release resources c. be awakened d. do nothing

d

If a system is deadlocked, no processes can a. run b. release resources c. be awakened d. All of the other choices

d

If there are 64 pages and the page size is 2048 words, what is the length of logical address? a. 14 bits b. 15 bits c. 16 bits d. 17 bits

d

Increasing file system performance is implemented by _____ a. Buffer cache b. Block Read Ahead c. Defragmenting Disks d. All of the other choices

d

One of the most important innovations of demand paging was that it made ____ feasible a. Memory demand b. Virtual demand c. Virtual paging d. Virtual memory.

d

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

d

The disk block in a partition that includes a magic number, the number of blocks in the file system and other key administrative information is called: a. Free block b. MBR c. Boot block d. Superblock

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

The main classes of I/O devices are: a. Stream devices b. Block devices c. Character devices d. Block devices and Character devices

d

The major operating system services provide mechanisms for secure and efficient are: a. Communication between processes b. File manipulation c. Execution of a program, I/O operations performed by it, and detecting and reporting errors caused by it d. All of the other choices

d

The process manager deals with the following except a. Thread management b. Resource management c. Process management d. Window management

d

The special files are: a. character special file b. block special file c. Neither a nor b d. Both a and b

d

Threads can be implemented in each of the following ways except a. Run-time libraries b. Operating system c. Java Virtual Machine d. Parent/child processes

d

Typical operations on a byte stream file do not include the following: a. Open(filename) b. Read(fileId, buffer, length) c. Seek(fileId, filePosition) d. Delete(fileId, filePosition, length)

d

What are the allocation methods of disk blocks for files: a. Contiguous allocation b. Linked allocation c. Indexed allocation 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

What is correct about trap instructions and interrupts? a. A trap instruction switch the execution mode of a CPU from the user mode to the kernel mode. b. A trap instruction is caused by a user program to invoke functions in the OS kernel c. An interrupt is caused by an external event d. All of the above

d

What is the correct approach with the "No preemption condition" to prevent Deadlock? a. Order resources numerically b. Request all resources initially c. Spool everything d. Take resources away

d

What is the main characteristic of embedded operating system? a. Multiple CPU b. Time-sharing c. Many I/O devices d. Restriction of memory size, speed of CPU, screen size, powers

d

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

Which are allocation methods of disk blocks for files? a. Contiguous allocation b. Linked allocation c. Indexed allocation d. All of the other choices

d

Which command can be used to display the contents of a file on the screen? a. ls b. grep c. dog d. cat

d

Which command is used to change a file's name? a. name b. move c. change -n d. mv

d

Which is a wrong statement about the quantum used in Round Robin algorithm ? a. If the quantum is very large, RR is essentially FCFS b. If the quantum is very small, the CPU efficiency is reduced c. A reasonable value of quantum is around 20-50 ms d. None of the above

d

Which is not a component of general structure of device drivers? a. Checking the input parameters to see if they are valid b. Checking if the device is currently in use c. Writing command sequence into controller's device registers d. Checking to see if the user is permitted to use the device

d

Which is not a goal of a scheduling algorithm for batch systems? a. CPU utilization b. Throughput c. Turnaround time d. Response time

d

Which is not an example of a resource that is commonly time-multiplexed? a. Network interface b. CPU c. Graphics accelerator d. Main memory

d

Which is the difference between personal computers and mainframe computers? a. Personal computers are always interactive b. Mainframe computers are mostly batch systems with many users c. Protection is much more important on mainframe computers d. All of the above

d

Which is the right order between the 4 I/O software layers? a. User-level I/O software, Device drivers, Interrupt handlers, Device-independent OS software b. User-level I/O software, Interrupt handlers, Device drivers, Device-independent OS software c. Device-independent OS software, user-level I/O software, Device drivers, Interrupt handlers d. User-level I/O software, Device-independent OS software, Device drivers, Interrupt handlers

d

Which of a system call is to allow the system free up disk space? a. OPEN b. CLOSE c. SEEK d. DELETE

d

Which of the following I/O software device layers is done by user-level software? a. Computing the track, sector, and head for a disk read b. Writing commands to the device registers c. Checking to see if the user is permitted to use the device d. Converting binary integers to ASCII for printing

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 file structure is widely used on large mainframe computers? a. Byte sequence b. Record sequence c. Ring d. Tree

d

Which of the following is a task of process management of OS? a. Process creation and deletion. b. Process suspension and resume c. Provision of mechanisms for process synchronization, Interprocess communication, Prevent or avoid deadlock d. All of the other choices

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 is not a CPU scheduling criterion? a. Burst time b. CPU utilization c. Throughput d. Response time

d

Which of the following is not a condition necessary for deadlock to exist? a. mutual-exclusion condition b. circular-wait condition c. hold and wait condition d. preemption condition

d

Which of the following is not a path name for the file /etc/passwd a. /etc/passwd b. /etc/../etc/passwd c. /etc/../etc/../etc/passwd d. None of the above

d

Which of the following is not a well-known techniques for organizing the physical storage blocks for a file? a. Contiguous block allocation b. Linked-list block allocation c. Sparse block allocation d. Indexed block allocation

d

Which of the following is not correct about hard links and symbolic links? a. Symbolic links need space to store the name and the file pointed to b. Hard links do not require extra disk space c. Symbolic links can point to files in the network d. Hard links can point to files on other machines

d

Which of the following is true about Atomic action on semaphores? a. Checking the value b. Changing the value c. Possibly going to sleep d. All of the other choices

d

Which of the following statements about segmentation is false? a. There are several linear address spaces b. The total address space can be more than the size of physical memory c. Sharing of procedures between different users can be facilitated d. None of the other choices

d

Which of the following statements about semaphores is true? a. A semaphore implementation should guarantee that processes do not suffer indefinite postponement, b. P and V (Down and Up) operations should be indivisible operations c. If several processes attempt a P(S) operation simultaneously, only one process should be allowed to proceed. All of the other choices d. All of the above

d

Which of the following statements about the task of device controller of I/O devices is correct? a. Convert serial bit stream to block of bytes b. Perform error correction as necessary c. Make available to main memory d. All of the other choices

d

Which of the following statements is incorrect about timesharing and multiprogramming systems? a. In a timesharing system, multiple users can access the system simultaneously b. In a multiprogramming system, one user can run several processes simultaneously c. All timesharing systems are multiprogramming systems d. All multiprogramming systems are timesharing systems

d

Which of the following statements is incorrect about user mode and kernel mode? a. In kernel mode, the OS can execute every instruction in the instruction set b. In user mode, user program can execute only a subset of instructions c. Having two modes of operation helps prevent user programs from accessing critical instructions d. None of the above

d

Which of the following synchronization mechanisms does not rely on busy-waiting ? a. Lock variables b. Strict alternation c. Peterson's algorithm d. Semaphores

d

____ allows a resource to be held by a process as long as it is needed. a. Mutual-exclusion condition b. Circular-wait condition c. Hold and wait condition d. No preemption condition

d

_____ is the command that writes the first 10 lines of a file to the screen. a. pr b. split c. tail d. head

d