Question 1
Question
A situation where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular order in which access takes place is called:
Answer
-
race condition
-
data consistency
-
starvation
-
mutual exclusion
Question 2
Question
Which one of the following is the address generated by CPU?
Answer
-
logical address
-
physical address
-
absolute address
-
none of the above
Question 3
Question
What is the ready state of a process?
Answer
-
when process is scheduled to run after some execution
-
none of the above
-
when process is using CPU
-
when process is unable to run until some task has been completed
Question 4
Question
Mutual exclusion can be provided by the:
Answer
-
none of the above maint
-
mutex locks
-
both
-
binary semaphores
Question 5
Question
What is a long-term scheduler?
Answer
-
it selects which process has to be executed next and allocates CPU
-
none of the above
-
it selects which process has to be brought into the ready queue
-
it selects which process has to remove from memory by swapping
Question 6
Question
Operating system maintains the page table for
Answer
-
each process
-
each thread
-
each instruction
-
each address
Question 7
Question
If a page number is not found in the TLB, then it is known as a:
Answer
-
TLB miss
-
buffer miss
-
TLB hit
-
page fault
Question 8
Question
Part of a program where the shared memory is accessed and which should be executed invisibly, is called:
Answer
-
semaphores
-
mutual exclusion
-
critical section
-
directory
Question 9
Question
In memory systems, boundary registers?
Answer
-
track the beginning and ending of programs
-
track page boundaries
-
are only necessary with fixed partitions
-
are used for temporary program variable storage
Question 10
Question
The resource vector defines
Answer
-
total amount of resources required for all processes
-
total amount of each resource in the system
-
total amount of each resource allocated to all processes
-
total amount of each resource NOT allocated to any process
Question 11
Question
When each process in the set is blocked awaiting for resource seized by another blocked process
Answer
-
it is a deadend
-
it is a deadlock
-
it is a softlock
-
it is a mortallock
Question 12
Question
The number of resources requested be a process:
Answer
-
must exceed the total number of resources available in the system
-
must always be equal to the total number of resources available in the system
-
must not exceed the total number of resources available in the system
-
must always be less than the total number of resources available in the system
Question 13
Question
What is interprocess communication?
Answer
-
communication between two process
-
communication between two threads of same process
-
none of the above
-
communication within the process
Question 14
Question
The degree of multi-programming is:
Answer
-
the number of processes executed per unit time
-
the number of processes in the I/O queue
-
the number of processes in the ready queue
-
the number of processes in memory
Question 15
Question
This matrix defines the amount of resources of type j requested by process i
Answer
-
Allocation matrix
-
Resource matrix
-
Request matrix
-
Claim matrix
Question 16
Question
To avoid the race condition, the number of processes that may be simultaneously inside their critical section is:
Question 17
Question
Which process can be affected by other processes executing in the system?
Answer
-
init process
-
cooperating process
-
child process
-
parent process
Question 18
Question
Which of the following registers are used by the processor to exchange data with memory?
Answer
-
MAR and MBR
-
PC and IR
-
Program status word
-
I/OAR and I/OBR
Question 19
Question
Which of the following registers are used by the processor to exchange data with input/output module?
Answer
-
MAR and MBR
-
PC and IR
-
Program status word
-
I/OAR and I/OBR
Question 20
Question
The main disadvantage of this technique: consumes a lot of processor time, because every word
Question 21
Question
The processor issues an I/O command to a module and then go on to some other useful work. The I/O module performs the requested action and alerts the processor to request service when it is ready to exchange data with the processor. The described technique is:
Question 22
Question
Which of the following is not a technique possible for I/O operations?
Question 23
Question
If a page table entry is not in main memory, then it is known as a:
Answer
-
page fault
-
buffer miss
-
TLB hit
-
TLB miss
Question 24
Question
We have
Ts = average (system) access time
T1 = access time of M1 (cache)
T2 = access time of M2 (main memory)
T3 = access time of M3 (disk)
H1 = hit ratio, fraction of time reference is found i M1
H2 = hit ratio, fraction of time reference is found i M2
The average time to access an item, in case the item in disk is:
Answer
-
Ts = H1*T1 + H2*T2 + (1-H2)*T3
-
Ts = H1*T1 + (1-H1)*(H1*T1 + H2*(T1 + T2) + (1 - H2)*(T2 + T3))
-
Ts = H1*T1 + (1-H1)*H2*(T2 + T3)
-
Ts = H1*T1 + (1-H1)*(H2*(T1 + T2) + (1 - H2)*(T1 + T2 + T3))
Question 25
Question
This chooses which block to replace when a new block is to be loaded into the cache and the cache already had all slots filled with other blocks:
Answer
-
replacement algorithm
-
write policy
-
cache size
-
locality of reference
Question 26
Question
If the accessed word is found in the faster memory, that is defined as a:
Question 27
Question
If the accessed word is not found in the faster memory, that is defined as a:
Question 28
Question
The processor contains a single data register, called
Question 29
Question
Which register contains the instruction most recently fetched?
Answer
-
instruction register
-
execution register
-
program counter
-
process counter
Question 30
Question
This register specifies the location in memory for the next read or write
Answer
-
Memory address register
-
I/OAR
-
Memory buffer register
-
I/OBR
Question 31
Question
Which of the following element of a computer system moves data between the computer and its external environment?
Answer
-
Main memory
-
Processor
-
System bus
-
I/O modules
Question 32
Question
This main disadvantage of this technique: consumes a lot of processor time, because every word of data that goes from memory to I/O module or from I/O module to memory must pass through the processor
Question 33
Question
The processor issues an I/O command to a separate module, by sending the type of operation (read/write), the address of the I/O device, the starting location in memory for data, number of words. Then the processor continues with other work. The module transfers the entire block of data to/from memory without going through the processor. The described technique is:
Question 34
Question
The processor issues an I/O command to a module and waits, periodically checking the status of the I/O module until it finds that the operation is complete.
The I/O module performs the requested action and then sets the appropriate bits in the I/O status register but takes no further action to alert the processor.
The described technique is:
Question 35
Question
The processor is executing "Load AC from memory" instruction. Choose the correct micro-instruction:
Answer
-
PC -> MAR
M -> MBR
MBR -> AC
IR -> MAR
M -> MBR
MBR -> AC
-
PC -> MBR
M -> MAR
MAR -> IR
IR -> MAR
M -> MBR
MBR -> AC
-
PC -> MAR
M -> MBR
MBR -> IR
IR -> MAR
M -> MBR
MBR -> AC
-
PC -> MAR
M -> MBR
MBR -> IR
IR -> MBR
M -> MAR
MAR -> AC
Question 36
Question
If there no interrupts, after each write operation, the processor must:
Answer
-
Load new PC value
-
Finish execution of current instruction
-
Save the PSW and PC onto control stack
-
Pause and remain idle until the I/O operation finishes
Question 37
Question
Complete the relationship concerning the memory systems: greater capacity
Answer
-
lower capacity
-
greater cost per bit
-
faster access speed
-
smaller cost per bit
Question 38
Question
User-visible registers minimize main memory references by optimizing register use
Question 39
Question
This register contains the data to be written into memory or which receives the data read from memory
Answer
-
I/OAR
-
memory buffer register
-
memory address register
-
I/OBR
Question 40
Question
Which of the following element of a computer system controls the operation of the computer and performs its data processing functions?
Answer
-
System bus
-
Main memory
-
I/O modules
-
Processor
Question 41
Question
The main disadvantages of this technique: there is a competition for bus usage
Question 42
Question
At the beginning of each instruction cycle, the processor fetches an instruction from the memory. The address of the instruction is held in
Question 43
Question
The smaller, more expensive, faster memory is:
Answer
-
Disk drive
-
Cache
-
Main memory
-
Register
Question 44
Question
There were no OS with
Question 45
Question
The principal objective of the time-sharing system is to
Question 46
Question
Serial processing was used
Question 47
Question
The programmer interacted directly with the computer hardware with
Question 48
Question
In operation system security and protection, availability is:
Answer
-
Concerned with the proper verification of the identity of users and the validity of messages or data
-
Assuring that users cannot read data for which access is unauthorized
-
Protection of data from unauthorized modification
-
Concerned with protecting the system against interruption
Question 49
Question
Choose the storage management responsibility for "The OS can achieve efficiency by assigning memory to jobs only as needed"
Answer
-
Process isolation
-
Protection and access control
-
Long-term storage
-
Support of modular programming
-
Automatic allocation and management
Question 50
Question
The limit register
Answer
-
Defines the size of the region of memory occupied by the process (in bytes or words)
-
Contains the index into the process list of the process currently controlling the processor
-
Points to the next instruction in that process to be executed
-
Contains the staring address of the region of memory occupied by the process
Question 51
Question
In operating system security and protection, authenticity is:
Answer
-
Concerned with the proper verification of the identity of users and the validity of messages or data
-
Assuring that users cannot read data for which access is unauthorized
-
Protection of data from unauthorized modification
-
Concerned with protecting the system against interruption
Question 52
Question
An application programs is developed by the
Answer
-
Application programmer
-
End user
-
Operating system
-
Hardware
Question 53
Question
"The OS as a User/Computer interface" corresponds to the following objective
Answer
-
Efficiency
-
Convenience
-
Ability to evolve
Question 54
Question 55
Question
If a process is executing in its critical section, then no other processes can be executing in their critical section. This condition is called
Answer
-
Synchronous exclusion
-
Critical exclusion
-
Asynchronous exclusion
-
Mutual exclusion
Question 56
Question
In operating system security and protection, confidentiality is:
Answer
-
Concerned with the proper verification of the identity of users and the validity of messages or data
-
Assuring that users cannot read data for which access is unauthorized
-
Protection of data from unauthorized modification
-
Concerned with protecting the system against interruption
Question 57
Question
In operating system security and protection, Data integrity is:
Answer
-
Concerned with the proper verification of the identity of users and the validity of messages or data
-
Assuring that users cannot read data for which access is unauthorized
-
Protection of data from unauthorized modification
-
Concerned with protecting the system against interruption
Question 58
Question
When the time required for the I/O operation is less that the time to complete the execution of instructions between write operations in the user program, it is:
Answer
-
Fast I/O wait
-
Slow I/O wait
-
Long I/O wait
-
Short I/O wait
Question 59
Question
This type of memory is nonvolatile:
Answer
-
Register
-
Secondary memory
-
Cache
-
Main memory
Question 60
Question
If the contents of a block in the cache are altered, then it is needed to save it back to main memory before replacing it. This is called:
Answer
-
write policy
-
mapping function
-
locality of reference
-
replacement algorithm
Question 61
Question
What is not a structural element of a computer system?
Answer
-
System bus
-
Main memory
-
Operating system
-
Processor
Question 62
Question
The main disadvantage of this technique: it is a time-consuming process that keeps the processor busy needlessly
Question 63
Question
Which of the following element of a computer system stores data and programs
Answer
-
Main memory
-
System bus
-
Processor
-
I/O modules
Question 64
Question
When an I/O device completes an I/O operation, the device issues an interrupt signal to the processor and then:
Answer
-
The processor stops execution of the current instruction without finishing it and responds to the interrupt
-
The processor loads the program counter with the entry location of the interrupt-handling routine
-
The processor saves information needed to resume the current program at the point if interrupt
-
The processor finishes execution of the current instruction before responding to the interrupt
Question 65
Question
Complete the relationship concerning the memory systems: greater capacity
Answer
-
lower capacity
-
slower access speed
-
greater cost per bit
-
faster access speed
Question 66
Question
Which register contains condition codes set by the processor hardware as the result of operations?
Answer
-
Program counter
-
Accumulator
-
Program status word
-
Stack pointer
Question 67
Question
Which of the following provides for communication among elements of a computer system?
Answer
-
main memory
-
system bus
-
processor
-
I/O modules
Question 68
Question
We have
Ts = average (system) access time
T1 = access time of M1 (cache)
T2 = access time of M2 (main memory)
T3 = access time of M3 (disk)
H1 = hit ratio, fraction of time reference is found i M1
H2 = hit ratio, fraction of time reference is found i M2
The average time to access an item, in case the item in main memory is:
Answer
-
Ts = H1*T1 + H2*T2 + (1-H2)*T3
-
Ts = H1*T1 + (1-H1)*(H1*T1 + H2*(T1 + T2) + (1 - H2)*(T2 + T3))
-
Ts = H1*T1 + (1-H1)*(T1+T2)
-
Ts = H1*T1 + (1-H1)*(H2*(T1 + T2) + (1 - H2)*(T1 + T2 + T3))
Question 69
Question
Control and status registers control the operation of the processor and the execution of programs
Question 70
Question
This type of system was developed at MIT by a group known as Project MAC for the IBM 709 in 1961
Question 71
Question
The concept of codes of operation (user mode, system mode) was introduced with
Question 72
Question
Short-term scheduler, or dispatcher, picks a process. Each process in the queue is given some time in turn. This strategy is called:
Answer
-
Round-robin technique
-
Prioritizing
-
Carousel technique
-
Merry-go-round technique
Question 73
Question
Central idea in this system was the use of piece of software known as the monitor:
Question 74
Question
'More than one program attempts to make use of a shared resource at the same time'. This is
Question 75
Question
The term was first used by the designers of Multics in 1960s:
Answer
-
Monitor
-
Process
-
Multiprogramming
-
Time sharing
Question 76
Answer
-
Application program
-
System programs
-
Opcodes
-
Processor registers
Question 77
Question
"When program shares memory and their execution is interleaved by the processor, they may interfere with each other by overwriting common memory areas in unpredictable ways. The result of a particular program depend on the activities of other programs in shared systems".
This is:
Question 78
Question
The state of a processor is defined by:
Answer
-
the activity just executed by the process
-
the current activity of the process
-
the final activity of the process
-
the activity to next be executed by the process
Question 79
Question
The hardware and software used in providing applications to a user can be viewed in:
Answer
-
classified fashion
-
layered fashion
-
sandwich fashion
-
leveled fashion
Question 80
Question
Suppose that a process is in "Blocked" state waiting for some I/O device.
When the service is completed, it goes to the:
Answer
-
Suspended state
-
Terminated state
-
Ready state
-
Running state
Question 81
Question
We have
Ts = average (system) access time
T1 = access time of M1 (cache)
T2 = access time of M2 (main memory)
T3 = access time of M3 (disk)
H1 = hit ratio, fraction of time reference is found i M1
H2 = hit ratio, fraction of time reference is found i M2
The average time to access an item, in case the item in cache is:
Answer
-
Ts = H1*T1 + H2*T2 + (1-H2)*T3
-
Ts = H1*T1 + (1-H1)*(H1*T1 + H2*(T1 + T2) + (1 - H2)*(T2 + T3))
-
Ts = H1*T1
-
Ts = H1*T1 + (1-H1)*(H2*(T1 + T2) + (1 - H2)*(T1 + T2 + T3))
Question 82
Question
The serial processing presented two main problems:
Answer
-
setup time
-
using a monitor
-
time slicing
-
multiprogramming
-
scheduling
Question 83
Question
The process index register:
Answer
-
contains the index into a process list of the process currently controlling the processor
-
define the region in memory occupied by the process
-
points to the next instruction in that process to be executed
-
contains the starting address of the region of memory occupied by the process
Question 84
Question
The concept of a batch operating system was developed to
Question 85
Question
Batch operating system were used
Question 86
Question
"More than one programs hung up waiting for each other".
This is
Question 87
Question
This contains the most frequently used functions in the OS:
Question 88
Question
The end user views a computer system in terms of:
Question 89
Question
Which of the following is not the state of a process?
Answer
-
new
-
waiting
-
terminated
-
ready
-
running
-
old
Question 90
Question
The fetched instruction is loaded into the
Question 91
Question
When the time required for the I/O operation will take much more time than executing a sequence of user instructions, it is:
Answer
-
Slow I/O wait
-
Long I/O wait
-
Fast I/O wait
-
Short I/O wait
Question 92
Question
The system handles multiple interactive jobs
Question 93
Question
A system clock generates interrupts at a rate of approximately one every 0.2 seconds. At each clock interrupt, the OS regained control and could assign the processor to another user. This technique is known as
Answer
-
Time scheduling
-
Time sliding
-
Time slicing
-
Time allocating
Question 94
Question
Choose the storage management responsibility for "Programmers should be able to define programs modules, and to create, destroy, and alter the size of modules dynamically":
Answer
-
Protection and access control
-
Long-term storage
-
automatic allocation and management
-
process isolation
-
support of modular programming
Question 95
Question
'Lost signals, duplicate signals received'. This is