Monday, February 25, 2019
Friday, February 22, 2019
Operating Sysem
1) Routine is not loaded until it is called. All routines are kept on disk in a relocatable load format. The main program is loaded into memory & is executed. This type of loading is called _________
1 Static loading
2 Dynamic loading
3 Dynamic linking
4 Overlays
Ans ) 3
2) Which of the following is crucial time while accessing data on the disk?
1 Seek time
2 Rotational time
3 Transmission time
4 Waiting time
Ans ) 1
3) The host repeatedly checks if the controller is busy until it is not. It is in a loop that status register's busy bit becomes clear. This is called _____________ and a mechanism for the hardware controller to notify the CPU that it is ready is called ___________.
1 Interrupt and Polling
2 Polling and Spooling
3 Polling and Interrupt
4 Deadlock and Starvation
Ans ) 3
4) Unix Operating System is an __________.
1 Time Sharing Operating System
2 Multi-User Operating System
3 Multi-tasking Operating System
4 All the Above
Ans ) 4
5) Which of the following memory allocation scheme suffers from External fragmentation?
1 Segmentation
2 Pure demand paging
3 Swapping
4 Paging
Ans ) 1
6) Information about a process is maintained in a _________.
1 Stack
2 Translation Lookaside Buffer
3 Process Control Block
4 Program Control Block
Ans ) 3
7) Distributed OS works on the ________ principle.
1 File Foundation
2 Single system image
3 Multi system image
4 Networking image
Ans ) 2
8) The problem of fragmentation arises in ________.
1 Static storage allocation
2 Stack allocation storage
3 Stack allocation with dynamic binding
4 Heap allocation
Ans ) 4
9) Which file system does DOS typically use ?
1 FAT16
2 FAT32
3 NTFS
4 WNFS
Ans ) 1
10) The program is known as _________ which interacts with the inner part of called kernel.
1 Compiler
2 Device Driver
3 Protocol
4 Shell
Ans ) 4
11) The time taken by the disk arm to locate the specific address of a sector for getting information is called __________.
1 Rotational Latency
2 Seek Time
3 Search Time
4 Response Time
Ans ) 2
12) Which file system does Windows 95 typically use ?
1 FAT16
2 FAT32
3 NTFS
4 LMFS
Ans ) 2
13) Identify the odd thing in the services of operating system.
1 Accounting
2 Protection
3 Error detection and correction
4 Dead lock handling
Ans ) 3
14) Cryptography technique is used in ________.
1 Polling
2 Job Scheduling
3 Protection
4 File Management
Ans ) 3
15) Which of the following is not advantage of multiprogramming?
1 Increased throughput
2 Shorter response time
3 Decreased operating system overhead
4 Ability to assign priorities to jobs
Ans ) 3
16) In ______ OS, the response time is very critical.
1 Multitasking
2 Batch
3 Online
4 Real-time
Ans ) 4
17) An optimal scheduling algorithm in terms of minimizing the average waiting time of a given set of processes is ________.
1 FCFS scheduling algorithm
2 Round robin scheduling algorithm
3 Shorest job - first scheduling algorithm
4 None of the above
Ans ) 3
18) Real time systems are ________.
1 Primarily used on mainframe computers
2 Used for monitoring events as they occur
3 Used for program development
4 Used for real time interactive users
Ans ) 2
19) Which technique was introduced because a single job could not keep both the CPU and the I/O devices busy?
1 Time-sharing
2 SPOOLing
3 Preemptive scheduling
4 Multiprogramming
Ans ) 4
20) Inter process communication can be done through __________.
1 Mails
2 Messages
3 System calls
4 Traps
Ans ) 2
21) In Priority Scheduling a priority number (integer) is associated with each process. The CPU is allocated to the process with the highest priority (smallest integer = highest priority). The problem of, Starvation ? low priority processes may never execute, is resolved by __________.
1 Terminating the process.
2 Aging
3 Mutual Exclusion
4 Semaphore
Ans ) 2
22) CPU performance is measured through ________.
1 Throughput
2 MHz
3 Flaps
4 None of the above
Ans ) 1
23) PCB =
1 Program Control Block
2 Process Control Block
3 Process Communication Block
4 None of the above
Ans ) 2
24) Software is a program that directs the overall operation of the computer, facilitates its use and interacts with the user. What are the different types of this software ?
1 Operating system
2 Language Compiler
3 Utilities
4 All of the above
Ans ) 4
25) A __________ is a software that manages the time of a microprocessor to ensure that all time critical events are processed as efficiently as possible. This software allows the system activities to be divided into multiple independent elements called tasks.
1 Kernel
2 Shell
3 Processor
4 Device Driver
Ans ) 1
26) The primary job of the operating system of a computer is to ________.
1 Command Resources
2 Manage Resources
3 Provide Utilities
4 Be user friendly
Ans ) 2
27) With the round robin CPU scheduling in a time-shared system ________.
1 Using very large time slice degenerates in to first come first served algorithm
2 Using extremely small time slices improve performance
3 Using extremely small time slices degenerate in to last in first out algorithm
4 Using medium sized time slices leads to shortest request time first algorithm
Ans ) 1
28) Which of the following is a criterion to evaluate a scheduling algorithm?
1 CPU Utilization: Keep CPU utilization as high as possible.
2 Throughput: number of processes completed per unit time.
3 Waiting Time: Amount of time spent ready to run but not running.
4 All of the above
Ans ) 4
29) Which of the following is contained in Process Control Block (PCB)?
1 Process Number
2 List of Open files
3 Memory Limits
4 All of the Above
Ans ) 4
30) Super computers typically employ _______.
1 Real time Operating system
2 Multiprocessors OS
3 desktop OS
4 None of the above
Ans ) 2
1) Consider the two statements.
(A) A network operating system, the users access remote resources in the same manner as local resource.
(B) In a distributed operating system, the user can access remote resources either by logging into the appropriate remote machine or transferring data from the remote machine to their own machine. Which of the statement is true?
1 A true, B false
2 B true, A false
3 Both A and B false
4 Both A and B true
Ans ) 3
2) Using Priority Scheduling algorithm, find the average waiting time for the following set of processes given with their priorities in the order: Process : Burst Time : Priority respectively .
P1 : 10 : 3 ,
P2 : 1 : 1 ,
P3 : 2 : 4 ,
P4 : 1 : 5 ,
P5 : 5 : 2.
1 8 milliseconds
2 8.2 milliseconds
3 7.75 milliseconds
4 3 milliseconds
Ans ) 2
3) Which of the following will determine your choice of systems software for your computer ?
1 Is the applications software you want to use compatible with it ?
2 Is it expensive ?
3 Is it compatible with your hardware ?
4 Both 1 and 3
Right Ans ) 4
Associate Ans) 4
4) What is a shell ?
1 It is a hardware component
2 It is a command interpreter
3 It is a part in compiler
4 It is a tool in CPU scheduling
Ans ) 2
5) The operating system manages ________.
1 Memory
2 Processor
3 Disk and I/O devices
4 All of the above
Ans ) 4
6) The Hardware mechanism that enables a device to notify the CPU is called __________.
1 Polling
2 Interrupt
3 System Call
4 None of the above
Ans ) 2
7) ___________ begins at the root and follows a path down to the specified file
1 Relative path name
2 Absolute path name
3 Standalone name
4 All of the above
Ans ) 2
8) Process State is a part of
1 Process Control block
2 Inode
3 File Allocation Table
4 None of the above
Ans ) 1
9) Virtual Memory is commonly implemented by __________.
1 Segmentation
2 Swapping
3 Demand Paging
4 None of the above
Ans ) 3
10) Virtual memory is __________.
1 An extremely large main memory
2 An extremely large secondary memory
3 An illusion of extremely large main memory
4 A type of memory used in super computers.
Ans ) 3
11) The kernel keeps track of the state of each task by using a data structure called __
1 Process control block
2 User control block
3 Memory control block
4 None of the above
Ans ) 1
12) A binary semaphore
1 has the values one or zero
2 is essential to binary computers
3 is used only for synchronisation
4 is used only for mutual exclusion
Ans ) 1
13) _________ page replacement alogorithm suffers from Belady's anamoly.
1 LRU
2 MRU
3 FIFO
4 LIFO
Ans ) 3
14) A program at the time of executing is called ________.
1 Dynamic program
2 Static program
3 Binded Program p
4 A Process
Ans ) 4
15) _________ is a high speed cache used to hold recently referenced page table entries a part of paged virtual memory
1 Translation Lookaside buffer
2 Inverse page table
3 Segmented page table
4 All the above
Ans ) 1
16) If you don¿t know which version of MS-DOS you are working with, which command will you use after booting your operating system ?
1 Format command
2 FAT command
3 VER command
4 DISK command
Ans ) 3
17) _______ OS pays more attention on the meeting of the time limits.
1 Distributed
2 Network
3 Real time
4 Online
Ans ) 3
18) A process said to be in ___________ state if it was waiting for an event that will never occur.
1 Safe
2 Unsafe
3 Starvation
4 Dead lock
Ans ) 4
19) The removal of process from active contention of CPU and reintroduce them into memory later is known as ____________.
1 Interrupt
2 Swapping
3 Signal
4 Thread
Ans ) 2
20) The problem of thrashing is effected scientifically by ________.
1 Program structure
2 Program size
3 Primary storage size
4 None of the above
Ans ) 1
21) Paging _________.
1 solves the memory fragmentation problem
2 allows modular programming
3 allows structured programming
4 avoids deadlock
Ans ) 1
22) Real time systems are ________.
1 Primarily used on mainframe computers
2 Used for monitoring events as they occur
3 Used for program development
4 Used for real time interactive users
Ans ) 2
23) A thread is a __________ process .
1 Heavy Weight
2 Mutliprocess
3 Inter Thread
4 Light wieght
Ans ) 4
24) _________ allocates the largest hole (free fragmant) available in the memory.
1 Best Fit
2 Worst Fit
3 First Fit
4 None of the above
Ans ) 2
25) Number of CPU registers in a system depends on ____________.
1 Operating system
2 Computer Architecture
3 Computer Organization
4 None of the above
Ans ) 2
26) A major problem with priority scheduling is _________.
1 Definite blocking
2 Starvation
3 Low priority
4 None of the above
Ans ) 2
27) A ___________ contains information about the file, including ownership, permissions, and location of the file contents.
1 File Control Block (FCB)
2 File
3 Device drivers
4 File system
Ans ) 1
28) Which directory implementation is used in most Operating System?
1 Single level directory structure
2 Two level directory structure
3 Tree directory structure
4 Acyclic directory structure
Ans ) 3
29) The term " Operating System " means ________.
1 A set of programs which controls computer working
2 The way a computer operator works
3 Conversion of high-level language in to machine level language
4 The way a floppy disk drive operates
Ans ) 1
30) The operating system of a computer serves as a software interface between the user and the ________.
1 Hardware
2 Peripheral
3 Memory
4 Screen
Ans ) 1
1) The collection of processes on the disk that is waiting to be brought into memory for execution forms the ___________
1 Ready queue
2 Device queue
3 Input queue
4 Priority queue
Ans ) 3
2) Demand paged memory allocation
1 allows the virtual address space to be independent of the physical memory
2 allows the virtual address space to be a multiple of the physical memory size
3 allows deadlock tobe detected in paging schemes
4 is present only in Windows NT
Ans ) 1
3) Which is not an Operating System ?
1 Windows 95
2 MS-DOS
3 Windows 3.1
4 Windows 2000
Ans ) 3
4) The operating system manages ________.
1 Memory
2 Processor
3 Disk and I/O devices
4 All of the above
Ans ) 4
5) It is not the layer of the Operating system.
1 Kernel
2 Shell
3 Application program
4 Critcal Section
Ans ) 4
6) ___________ begins at the root and follows a path down to the specified file
1 Relative path name
2 Absolute path name
3 Standalone name
4 All of the above
Ans ) 2
7) Who is called a supervisor of computer acitvity ?
1 CPU
2 Operating system
3 Control unit
4 Application Program
Ans ) 2
8) Consider the two statements. (A) Protection is an internal problem. (B) Security is considered as an external environment within which the system works. Which of the statement is not true?
1 Only A
2 Only B
3 Both A and B
4 None of the above
Ans ) 4
9) The process related to process control, file management, device management, information about system and communication that is requested by any higher level language can be performed by __________.
1 Editors
2 Compilers
3 System Call
4 Caching
Ans ) 3
10) Mutual exclusion
1 if one process is in a critical region others are excluded
2 prevents deadlock
3 requires semaphores to implement
4 is found only in the Windows NT operating system
Ans ) 1
11) Which scheduler controls the degree of multiprogramming?
1 Short term scheduler
2 Long term scheduler
3 Middle term scheduler
4 None of the above
Ans ) 2
12) What is the name of the software which can be legally compiled and often used for free?
1 Shareware program
2 Public domain program
3 Firmware program
4 Mind Ware
Ans ) 2
13) The problem of fragmentation arises in ________.
1 Static storage allocation
2 Stack allocation storage
3 Stack allocation with dynamic binding
4 Heap allocation
Ans ) 4
14) In interactive environments such as time-sharing systems, the primary requirement is to provide reasonably good response time and in general, to share system resources equitably. In such situations, the scheduling algorithm that is most popularly applied is ________.
1 Shortest Remaining Time Next (SRTN) Scheduling
2 Priority Based Preemptive Scheduling
3 Round Robin Scheduling
4 None of the above
Ans ) 3
15) Thrashing occurs ________.
1 when excessive swapping takes place
2 when you thrash your computer
3 whenever deadlock occurs
4 when no swapping takes place
Ans ) 1
16) Boundary registers ________.
1 Are available in temporary program variable storage
2 Are only necessary with fixed partitions
3 Track the beginning and ending the program
4 Track page boundaries
Ans ) 3
17) The principle of locality of reference justifies the use of ________.
1 Virtual Memory
2 Interrupts
3 Main memory
4 Cache memory
Ans ) 4
18) The section of code which accesses shared variables is called as __________.
1 Critical section
2 Block
3 Procedure
4 Semaphore
Ans ) 1
19) Thrashing ________.
1 Reduces page I/O
2 Decreases the degree of multiprogramming
3 Implies excessive page I/O
4 Improve the system performance
Ans ) 3
20) In memory management , a technique called as paging, physical memory is broken into fixed-sized blocks called ___________.
1 Pages
2 Frames
3 Blocks
4 Segments
Ans ) 2
21) The state of a process after it encounters an I/O instruction is __________.
1 Ready
2 Blocked/Waiting
3 Idle
4 Running
Ans ) 2
22) In one of the deadlock prevention methods, impose a total ordering of all resource types, and require that each process requests resources in an increasing order of enumeration. This voilates the _______________ condition of deadlock
1 Mutual exclusion
2 Hold and Wait
3 Circular Wait
4 No Preemption
Ans ) 3
23) Which of the following file name extension suggests that the file is Backup copy of another file ?
1 TXT
2 COM
3 BAS
4 BAK
Ans ) 4
24) The degree of Multiprogramming is controlled by
1 CPU Scheduler
2 Context Switching
3 Long-term Scheduler
4 Medium term Scheduler
Ans ) 3
25) The higher versions of operating systems are so written that programs designed for earlier versions can still be run. What is it called ?
1 Up gradiability
2 Upward mobility
3 Universality
4 Upward Compatibility
Ans ) 4
26) A scheduling algorithm is fair
1 if no process faces starvation
2 if a process is starved, detect it and run it with high priority
3 if it uses semaphores
4 only if a queue is used for scheduling
Ans ) 1
27) A critical region
1 is a piece of code which only one process executes at a time
2 is a region prone to deadlock
3 is a piece of code which only a finite number of processes execute
4 is found only in Windows NT operation system
Ans ) 1
28) Semaphore can be used for solving __________.
1 Wait & signal
2 Deadlock
3 Synchronization
4 Priority
Ans ) 3
29) The operating system of a computer serves as a software interface between the user and the ________.
1 Hardware
2 Peripheral
3 Memory
4 Screen
Ans ) 1
30) What is the name of the software which deals with the running of the actual computer and not with the programming problems?
1 Operating system
2 System program
3 Object program
4 Source program
Ans ) 2
1) Round robin scheduling is essentially the preemptive version of ________.
1 FIFO
2 Shortest job first
3 Shortes remaining
4 Longest time first
Right Ans ) 1
2) A page fault occurs
1 when the page is not in the memory
2 when the page is in the memory
3 when the process enters the blocked state
4 when the process is in the ready state
Right Ans ) 1
3) Which of the following will determine your choice of systems software for your computer ?
1 Is the applications software you want to use compatible with it ?
2 Is it expensive ?
3 Is it compatible with your hardware ?
4 Both 1 and 3
Right Ans ) 4
4) Let S and Q be two semaphores initialized to 1, where P0 and P1 processes the following statements wait(S);wait(Q); ---; signal(S);signal(Q) and wait(Q); wait(S);---;signal(Q);signal(S); respectively. The above situation depicts a _________ .
1 Semaphore
2 Deadlock
3 Signal
4 Interrupt
Right Ans ) 2
5) What is a shell ?
1 It is a hardware component
2 It is a command interpreter
3 It is a part in compiler
4 It is a tool in CPU scheduling
Right Ans ) 2
6) Routine is not loaded until it is called. All routines are kept on disk in a relocatable load format. The main program is loaded into memory & is executed. This type of loading is called _________
1 Static loading
2 Dynamic loading
3 Dynamic linking
4 Overlays
Right Ans ) 3
7) In the blocked state
1 the processes waiting for I/O are found
2 the process which is running is found
3 the processes waiting for the processor are found
4 none of the above
Right Ans ) 1
8) What is the memory from 1K - 640K called ?
1 Extended Memory
2 Normal Memory
3 Low Memory
4 Conventional Memory
Right Ans ) 4
9) Virtual memory is __________.
1 An extremely large main memory
2 An extremely large secondary memory
3 An illusion of extremely large main memory
4 A type of memory used in super computers.
Right Ans ) 3
10) The process related to process control, file management, device management, information about system and communication that is requested by any higher level language can be performed by __________.
1 Editors
2 Compilers
3 System Call
4 Caching
Right Ans ) 3
11) If the Disk head is located initially at 32, find the number of disk moves required with FCFS if the disk queue of I/O blocks requests are 98,37,14,124,65,67.
1 310
2 324
3 315
4 321
Right Ans ) 4
12) Multiprogramming systems ________.
1 Are easier to develop than single programming systems
2 Execute each job faster
3 Execute more jobs in the same time
4 Are used only on large main frame computers
Right Ans ) 3
13) Which is not the state of the process ?
1 Blocked
2 Running
3 Ready
4 Privileged
Right Ans ) 4
14) The solution to Critical Section Problem is : Mutual Exclusion, Progress and Bounded Waiting.
1 The statement is false
2 The statement is true.
3 The statement is contradictory.
4 None of the above
Right Ans ) 2
15) The problem of thrashing is effected scientifically by ________.
1 Program structure
2 Program size
3 Primary storage size
4 None of the above
Right Ans ) 1
16) The state of a process after it encounters an I/O instruction is __________.
1 Ready
2 Blocked/Waiting
3 Idle
4 Running
Right Ans ) 2
17) The number of processes completed per unit time is known as __________.
1 Output
2 Throughput
3 Efficiency
4 Capacity
Right Ans ) 2
18) _________ is the situation in which a process is waiting on another process,which is also waiting on another process ... which is waiting on the first process. None of the processes involved in this circular wait are making progress.
1 Deadlock
2 Starvation
3 Dormant
4 None of the above
Right Ans ) 1
19) Which of the following file name extension suggests that the file is Backup copy of another file ?
1 TXT
2 COM
3 BAS
4 BAK
Right Ans ) 4
20) Which technique was introduced because a single job could not keep both the CPU and the I/O devices busy?
1 Time-sharing
2 SPOOLing
3 Preemptive scheduling
4 Multiprogramming
Right Ans ) 4
21) A critical region
1 is a piece of code which only one process executes at a time
2 is a region prone to deadlock
3 is a piece of code which only a finite number of processes execute
4 is found only in Windows NT operation system
Right Ans ) 1
22) The mechanism that bring a page into memory only when it is needed is called _____________
1 Segmentation
2 Fragmentation
3 Demand Paging
4 Page Replacement
Right Ans ) 3
23) PCB =
1 Program Control Block
2 Process Control Block
3 Process Communication Block
4 None of the above
Right Ans ) 2
24) FIFO scheduling is ________.
1 Preemptive Scheduling
2 Non Preemptive Scheduling
3 Deadline Scheduling
4 Fair share scheduling
Right Ans ) 2
25) Switching the CPU to another Process requires to save state of the old process and loading new process state is called as __________.
1 Process Blocking
2 Context Switch
3 Time Sharing
4 None of the above
Right Ans ) 2
26) Which directory implementation is used in most Operating System?
1 Single level directory structure
2 Two level directory structure
3 Tree directory structure
4 Acyclic directory structure
Right Ans ) 3
27) The Banker¿s algorithm is used
1 to prevent deadlock in operating systems
2 to detect deadlock in operating systems
3 to rectify a deadlocked state
4 none of the above
Right Ans ) 1
28) A thread
1 is a lightweight process where the context switching is low
2 is a lightweight process where the context swithching is high
3 is used to speed up paging
4 none of the above
Right Ans ) 1
29) ______ is a high level abstraction over Semaphore.
1 Shared memory
2 Message passing
3 Monitor
4 Mutual exclusion
Right Ans ) 3
30) A tree sturctured file directory system
1 allows easy storage and retrieval of file names
2 is a much debated unecessary feature
3 is not essential when we have millions of files
4 none of the above
Right Ans ) 1
1) Using Priority Scheduling algorithm, find the average waiting time for the following set of processes given with their priorities in the order: Process : Burst Time : Priority respectively . P1 : 10 : 3 , P2 : 1 : 1 , P3 : 2 : 4 , P4 : 1 : 5 , P5 : 5 : 2.
1 8 milliseconds
2 8.2 milliseconds
3 7.75 milliseconds
4 3 milliseconds
Right Ans ) 2
2) Routine is not loaded until it is called. All routines are kept on disk in a relocatable load format. The main program is loaded into memory & is executed. This type of loading is called _________
1 Static loading
2 Dynamic loading
3 Dynamic linking
4 Overlays
Right Ans ) 3
3) In the running state
1 only the process which has control of the processor is found
2 all the processes waiting for I/O to be completed are found
3 all the processes waiting for the processor are found
4 none of the above
Right Ans ) 1
4) The Purpose of Co-operating Process is __________.
1 Information Sharing
2 Convenience
3 Computation Speed-Up
4 All of the above
Right Ans ) 4
5) The kernel of the operating system remains in the primary memory because ________.
1 It is mostly called (used)
2 It manages all interrupt calls
3 It controls all operations in process
4 It is low level
Right Ans ) 1
6) The process related to process control, file management, device management, information about system and communication that is requested by any higher level language can be performed by __________.
1 Editors
2 Compilers
3 System Call
4 Caching
Right Ans ) 3
7) Which of the following disk scheduling techniques has a drawback of starvation ?
1 SCAN
2 SSTF
3 FCFS
4 LIFO
Right Ans ) 2
8) Multiprogramming systems ________.
1 Are easier to develop than single programming systems
2 Execute each job faster
3 Execute more jobs in the same time
4 Are used only on large main frame computers
Right Ans ) 3
9) Under multiprogramming, turnaround time for short jobs is usually ________ and that for long jobs is slightly ___________.
1 Lengthened; Shortened
2 Shortened; Lengthened
3 Shortened; Shortened
4 Shortened; Unchanged
Right Ans ) 2
10) Multiprocessing ________.
1 Make the operating system simpler
2 Allows multiple processes to run simultaneously
3 Is completely understood by all major computer vendors
4 Allows the same computer to have the multiple processors
Right Ans ) 4
11) Which is not the state of the process ?
1 Blocked
2 Running
3 Ready
4 Privileged
Right Ans ) 4
12) A set of resources' allocations such that the system can allocate resources to each process in some order, and still avoid a deadlock is called ________.
1 Unsafe state
2 Safe state
3 Starvation
4 Greeedy allocation
Right Ans ) 2
13) The principle of locality of reference justifies the use of ________.
1 Virtual Memory
2 Interrupts
3 Main memory
4 Cache memory
Right Ans ) 4
14) What is the first step in performing an operating system upgrade ?
1 Partition the drive
2 Format the drive
3 Backup critical data
4 Backup old operating system
Right Ans ) 3
15) The technique, for sharing the time of a computer among several jobs, which switches jobs so rapidly such that each job appears to have the computer to itself, is called ________.
1 Time Sharing
2 Time out
3 Time domain
4 Multitasking
Right Ans ) 1
16) In a virtural memory environment
1 segmentation and page tables are stored in the cache and do not add any substantial overhead
2 slow down the computer system considerable
3 segmentation and page tables are stored in the RAM
4 none of the above
Right Ans ) 3
17) If all page frames are initially empty, and a process is allocated 3 page frames in real memory and references its pages in the order 1 2 3 2 4 5 2 3 2 4 1 and the page replacement is FIFO, the total number of page faults caused by the process will be __________.
1 10
2 7
3 8
4 9
Right Ans ) 4
18) Situations where two or more processes are reading or writing some shared data and the final results depends on the order of usage of the shared data, are called ________.
1 Race conditions
2 Critical section
3 Mutual exclusion
4 Dead locks
Right Ans ) 1
19) When two or more processes attempt to access the same resource a _________ occurs.
1 Critical section
2 Fight
3 Communication problem
4 Race condition
Right Ans ) 4
20) Which technique was introduced because a single job could not keep both the CPU and the I/O devices busy?
1 Time-sharing
2 SPOOLing
3 Preemptive scheduling
4 Multiprogramming
Right Ans ) 4
21) _________ allocates the largest hole (free fragmant) available in the memory.
1 Best Fit
2 Worst Fit
3 First Fit
4 None of the above
Right Ans ) 2
22) A process is starved
1 if it is permanently waiting for a resource
2 if semaphores are not used
3 if a queue is not used for scheduling
4 if demand paging is not properly implemented
Right Ans ) 1
23) The degree of Multiprogramming is controlled by
1 CPU Scheduler
2 Context Switching
3 Long-term Scheduler
4 Medium term Scheduler
Right Ans ) 3
24) The time taken to bring the desired track/cylinder under the head is _________.
1 Seek time
2 Latency time
3 Transfer time
4 Read time
Right Ans ) 1
25) Replace the page that will not be used for the longest period of time. This principle is adopted by ____________.
1 FIFO Page replacement algorithm
2 Optimal Page replacement algorithm
3 Round robin scheduling algorithm
4 SCAN scheduling algorithm
Right Ans ) 3
26) Which of the following is a criterion to evaluate a scheduling algorithm?
1 CPU Utilization: Keep CPU utilization as high as possible.
2 Throughput: number of processes completed per unit time.
3 Waiting Time: Amount of time spent ready to run but not running.
4 All of the above
Right Ans ) 4
27) The operating system of a computer serves as a software interface between the user and the ________.
1 Hardware
2 Peripheral
3 Memory
4 Screen
Right Ans ) 1
28) Super computers typically employ _______.
1 Real time Operating system
2 Multiprocessors OS
3 desktop OS
4 None of the above
Right Ans ) 2
29) A process that is based on IPC mechanism which executes on different systems and can communicate with other processes using message based communication, is called ________.
1 Local Procedure Call
2 Inter Process Communication
3 Remote Procedure Call
4 Remote Machine Invocation
Right Ans ) 3
30) A process is
1 program in execution
2 a concurrent program
3 any sequential program
4 something which prevents deadlock
Right Ans ) 1
1) The high paging activity is called ________.
1 Inter process communication
2 Thrashing
3 Context Switch
4 None of the above
Right Ans ) 2
2) The Hardware mechanism that enables a device to notify the CPU is called __________.
1 Polling
2 Interrupt
3 System Call
4 None of the above
Right Ans ) 2
3) In the running state
1 only the process which has control of the processor is found
2 all the processes waiting for I/O to be completed are found
3 all the processes waiting for the processor are found
4 none of the above
Right Ans ) 1
4) Which of the following is crucial time while accessing data on the disk?
1 Seek time
2 Rotational time
3 Transmission time
4 Waiting time
Right Ans ) 1
5) Process State is a part of
1 Process Control block
2 Inode
3 File Allocation Table
4 None of the above
Right Ans ) 1
6) Who is called a supervisor of computer acitvity ?
1 CPU
2 Operating system
3 Control unit
4 Application Program
Right Ans ) 2
7) Virtual memory is __________.
1 An extremely large main memory
2 An extremely large secondary memory
3 An illusion of extremely large main memory
4 A type of memory used in super computers.
Right Ans ) 3
8) The kernel keeps track of the state of each task by using a data structure called __
1 Process control block
2 User control block
3 Memory control block
4 None of the above
Right Ans ) 1
9) Which of the following disk scheduling techniques has a drawback of starvation ?
1 SCAN
2 SSTF
3 FCFS
4 LIFO
Right Ans ) 2
10) A binary semaphore
1 has the values one or zero
2 is essential to binary computers
3 is used only for synchronisation
4 is used only for mutual exclusion
Right Ans ) 1
11) _________ page replacement alogorithm suffers from Belady's anamoly.
1 LRU
2 MRU
3 FIFO
4 LIFO
Right Ans ) 3
12) _________ is a high speed cache used to hold recently referenced page table entries a part of paged virtual memory
1 Translation Lookaside buffer
2 Inverse page table
3 Segmented page table
4 All the above
Right Ans ) 1
13) _________ does the job of allocating a process to the processor.
1 Long term scheduler
2 Short term scheduler
3 Medium term scheduler
4 Dispatcher
Right Ans ) 4
14) In interactive environments such as time-sharing systems, the primary requirement is to provide reasonably good response time and in general, to share system resources equitably. In such situations, the scheduling algorithm that is most popularly applied is ________.
1 Shortest Remaining Time Next (SRTN) Scheduling
2 Priority Based Preemptive Scheduling
3 Round Robin Scheduling
4 None of the above
Right Ans ) 3
15) In the multi-programming environment, the main memory consisting of _________ number of process.
1 Greater than 100
2 Only one
3 Greater than 50
4 More than one
Right Ans ) 4
16) In a multithreaded environment _______.
1 Each thread is allocated with new memory from main memory.
2 Main thread terminates after the termination of child threads.
3 Every process can have only one thread.
4 None of the above
Right Ans ) 2
17) Which of the following statement is not true?
1 Multiprogramming implies multitasking
2 Multi-user does not imply multiprocessing
3 Multitasking does not imply multiprocessing
4 Multithreading implies multi-user
Right Ans ) 4
18) In one of the deadlock prevention methods, impose a total ordering of all resource types, and require that each process requests resources in an increasing order of enumeration. This voilates the _______________ condition of deadlock
1 Mutual exclusion
2 Hold and Wait
3 Circular Wait
4 No Preemption
Right Ans ) 3
19) In the ___________ method of data transfer, the participation of the processor is eliminated during data transfer.
1 Buffering
2 Caching
3 Direct Memory Access
4 Indirect Memory Access
Right Ans ) 3
20) A thread is a __________ process .
1 Heavy Weight
2 Mutliprocess
3 Inter Thread
4 Light wieght
Right Ans ) 4
21) Data reside in file on disk under DOS environment, which of the following file name is invalid ?
1 OSCONCEPTS.doc
2 RAW
3 COMPAQ.BOOK
4 JUMPSTART.BOS
Right Ans ) 3
22) In Priority Scheduling a priority number (integer) is associated with each process. The CPU is allocated to the process with the highest priority (smallest integer = highest priority). The problem of, Starvation ? low priority processes may never execute, is resolved by __________.
1 Terminating the process.
2 Aging
3 Mutual Exclusion
4 Semaphore
Right Ans ) 2
23) CPU Scheduling is the basis of _________ operating system
1 Batch
2 Real time
3 Multiprogramming
4 Monoprogramming
Right Ans ) 3
24) A major problem with priority scheduling is _________.
1 Definite blocking
2 Starvation
3 Low priority
4 None of the above
Right Ans ) 2
25) ________ scheduler selects the jobs from the pool of jobs and loads into the ready queue.
1 Long term
2 Short term
3 Medium term
4 None of the above
Right Ans ) 1
26) Which directory implementation is used in most Operating System?
1 Single level directory structure
2 Two level directory structure
3 Tree directory structure
4 Acyclic directory structure
Right Ans ) 3
27) Saving the state of the old process and loading the saved state of the new process is called ________.
1 Context Switch
2 State
3 Multi programming
4 None of the above
Right Ans ) 1
28) The term " Operating System " means ________.
1 A set of programs which controls computer working
2 The way a computer operator works
3 Conversion of high-level language in to machine level language
4 The way a floppy disk drive operates
Right Ans ) 1
29) Resource locking ________.
1 Allows multiple tasks to simultaneously use resource
2 Forces only one task to use any resource at any time
3 Can easily cause a dead lock condition
4 Is not used for disk drives
Right Ans ) 2
30) A thread
1 is a lightweight process where the context switching is low
2 is a lightweight process where the context swithching is high
3 is used to speed up paging
4 none of the above
Right Ans ) 1
Short answers
1.Explain the concept of Reentrancy.
It is a useful, memory-saving technique for multiprogrammed timesharing systems. A Reentrant Procedure is one in which multiple users can share a single copy of a program during the same period. Reentrancy has 2 key aspects: The program code cannot modify itself, and the local data for each user process must be stored separately. Thus, the permanent part is the code, and the temporary part is the pointer back to the calling program and local variables used by that program. Each execution instance is called activation. It executes the code in the permanent part, but has its own copy of local variables/parameters. The temporary part associated with each activation is the activation record. Generally, the activation record is kept on the stack.
Note: A reentrant procedure can be interrupted and called by an interrupting program, and still execute correctly on returning to the procedure.
2.Explain Belady's Anomaly.
Also called FIFO anomaly. Usually, on increasing the number of frames allocated to a process' virtual memory, the process execution is faster, because fewer page faults occur. Sometimes, the reverse happens, i.e., the execution time increases even when more frames are allocated to the process. This is Belady's Anomaly. This is true for certain page reference patterns.
3.What is a binary semaphore? What is its use?
A binary semaphore is one, which takes only 0 and 1 as values. They are used to implement mutual exclusion and synchronize concurrent processes.
4.What is thrashing?
It is a phenomenon in virtual memory schemes when the processor spends most of its time swapping pages, rather than executing instructions. This is due to an inordinate number of page faults.
5.List the Coffman's conditions that lead to a deadlock.
Mutual Exclusion: Only one process may use a critical resource at a time.
Hold & Wait: A process may be allocated some resources while waiting for others.
No Pre-emption: No resource can be forcible removed from a process holding it.
It is a useful, memory-saving technique for multiprogrammed timesharing systems. A Reentrant Procedure is one in which multiple users can share a single copy of a program during the same period. Reentrancy has 2 key aspects: The program code cannot modify itself, and the local data for each user process must be stored separately. Thus, the permanent part is the code, and the temporary part is the pointer back to the calling program and local variables used by that program. Each execution instance is called activation. It executes the code in the permanent part, but has its own copy of local variables/parameters. The temporary part associated with each activation is the activation record. Generally, the activation record is kept on the stack.
Note: A reentrant procedure can be interrupted and called by an interrupting program, and still execute correctly on returning to the procedure.
2.Explain Belady's Anomaly.
Also called FIFO anomaly. Usually, on increasing the number of frames allocated to a process' virtual memory, the process execution is faster, because fewer page faults occur. Sometimes, the reverse happens, i.e., the execution time increases even when more frames are allocated to the process. This is Belady's Anomaly. This is true for certain page reference patterns.
3.What is a binary semaphore? What is its use?
A binary semaphore is one, which takes only 0 and 1 as values. They are used to implement mutual exclusion and synchronize concurrent processes.
4.What is thrashing?
It is a phenomenon in virtual memory schemes when the processor spends most of its time swapping pages, rather than executing instructions. This is due to an inordinate number of page faults.
5.List the Coffman's conditions that lead to a deadlock.
Mutual Exclusion: Only one process may use a critical resource at a time.
Hold & Wait: A process may be allocated some resources while waiting for others.
No Pre-emption: No resource can be forcible removed from a process holding it.
Circular Wait: A closed chain of processes exist such that each process holds at least one resource needed by another process in the chain.
6.What are short-, long- and medium-term scheduling?
Long term scheduler determines which programs are admitted to the system for processing. It controls the degree of multiprogramming. Once admitted, a job becomes a process.
Medium term scheduling is part of the swapping function. This relates to processes that are in a blocked or suspended state. They are swapped out of real-memory until they are ready to execute. The swapping-in decision is based on memory-management criteria.
Short term scheduler, also know as a dispatcher executes most frequently, and makes the finest-grained decision of which process should execute next. This scheduler is invoked whenever an event occurs. It may lead to interruption of one process by preemption.
7.What are turnaround time and response time?
Turnaround time is the interval between the submission of a job and its completion. Response time is the interval between submission of a request, and the first response to that request.
8.What are the typical elements of a process image?
User data: Modifiable part of user space. May include program data, user stack area, and programs that may be modified.
User program: The instructions to be executed.
System Stack: Each process has one or more LIFO stacks associated with it. Used to store parameters and calling addresses for procedure and system calls.
Process control Block (PCB): Info needed by the OS to control processes.
9.What is the Translation Lookaside Buffer (TLB)?
In a cached system, the base addresses of the last few referenced pages is maintained in registers called the TLB that aids in faster lookup. TLB contains those page-table entries that have been most recently used. Normally, each virtual memory reference causes 2 physical memory accesses-- one to fetch appropriate page-table entry, and one to fetch the desired data. Using TLB in-between, this is reduced to just one physical memory access in cases of TLB-hit.
10.What is the resident set and working set of a process?
Resident set is that portion of the process image that is actually in real-memory at a particular instant. Working set is that subset of resident set that is actually needed for execution. (Relate this to the variable-window size method for swapping techniques.)
11.When is a system in safe state?
The set of dispatchable processes is in a safe state if there exists at least one temporal order in which all processes can be run to completion without resulting in a deadlock.
12.What is cycle stealing?
We encounter cycle stealing in the context of Direct Memory Access (DMA). Either the DMA controller can use the data bus when the CPU does not need it, or it may force the CPU to temporarily suspend operation. The latter technique is called cycle stealing. Note that cycle stealing can be done only at specific break points in an instruction cycle.
13.What is meant by arm-stickiness?
If one or a few processes have a high access rate to data on one track of a storage disk, then they may monopolize the device by repeated requests to that track. This generally happens with most common device scheduling algorithms (LIFO, SSTF, C-SCAN, etc). High-density multisurface disks are more likely to be affected by this than low density ones.
14.What are the stipulations of C2 level security?
C2 level security provides for:
Discretionary Access Control
Identification and Authentication
Auditing
Resource reuse
15.What is busy waiting?
The repeated execution of a loop of code while waiting for an event to occur is called busy-waiting. The CPU is not engaged in any real productive activity during this period, and the process does not progress toward completion.
16.Explain the popular multiprocessor thread-scheduling strategies.
Load Sharing: Processes are not assigned to a particular processor. A global queue of threads is maintained. Each processor, when idle, selects a thread from this queue. Note that load balancing refers to a scheme where work is allocated to processors on a more permanent basis.
Gang Scheduling: A set of related threads is scheduled to run on a set of processors at the same time, on a 1-to-1 basis. Closely related threads / processes may be scheduled this way to reduce synchronization blocking, and minimize process switching. Group scheduling predated this strategy.
Dedicated processor assignment: Provides implicit scheduling defined by assignment of threads to processors. For the duration of program execution, each program is allocated a set of processors equal in number to the number of threads in the program. Processors are chosen from the available pool.
Dynamic scheduling: The number of thread in a program can be altered during the course of execution.
17.When does the condition 'rendezvous' arise?
In message passing, it is the condition in which, both, the sender and receiver are blocked until the message is delivered.
18.What is a trap and trapdoor?
Trapdoor is a secret undocumented entry point into a program used to grant access without normal methods of access authentication. A trap is a software interrupt, usually the result of an error condition.
19.What are local and global page replacements?
Local replacement means that an incoming page is brought in only to the relevant process' address space. Global replacement policy allows any page frame from any process to be replaced. The latter is applicable to variable partitions model only.
20.Define latency, transfer and seek time with respect to disk I/O.
Seek time is the time required to move the disk arm to the required track. Rotational delay or latency is the time it takes for the beginning of the required sector to reach the head. Sum of seek time (if any) and latency is the access time. Time taken to actually transfer a span of data is transfer time.
21.Describe the Buddy system of memory allocation.
Free memory is maintained in linked lists, each of equal sized blocks. Any such block is of size 2^k. When some memory is required by a process, the block size of next higher order is chosen, and broken into two. Note that the two such pieces differ in address only in their kth bit. Such pieces are called buddies. When any used block is freed, the OS checks to see if its buddy is also free. If so, it is rejoined, and put into the original free-block linked-list.
22.What is time-stamping?
It is a technique proposed by Lamport, used to order events in a distributed system without the use of clocks. This scheme is intended to order events consisting of the transmission of messages. Each system 'i' in the network maintains a counter Ci. Every time a system transmits a message, it increments its counter by 1 and attaches the time-stamp Ti to the message. When a message is received, the receiving system 'j' sets its counter Cj to 1 more than the maximum of its current value and the incoming time-stamp Ti. At each site, the ordering of messages is determined by the following rules: For messages x from site i and y from site j, x precedes y if one of the following conditions holds....(a) if Ti
23.How are the wait/signal operations for monitor different from those for semaphores?
If a process in a monitor signal and no task is waiting on the condition variable, the signal is lost. So this allows easier program design. Whereas in semaphores, every operation affects the value of the semaphore, so the wait and signal operations should be perfectly balanced in the program.
24.In the context of memory management, what are placement and replacement algorithms?
Placement algorithms determine where in available real-memory to load a program. Common methods are first-fit, next-fit, best-fit. Replacement algorithms are used when memory is full, and one process (or part of a process) needs to be swapped out to accommodate a new program. The replacement algorithm determines which are the partitions to be swapped out.
25.In loading programs into memory, what is the difference between load-time dynamic linking and run-time dynamic linking?
For load-time dynamic linking: Load module to be loaded is read into memory. Any reference to a target external module causes that module to be loaded and the references are updated to a relative address from the start base address of the application module.
With run-time dynamic loading: Some of the linking is postponed until actual reference during execution. Then the correct module is loaded and linked.
26.What are demand- and pre-paging?
With demand paging, a page is brought into memory only when a location on that page is actually referenced during execution. With pre-paging, pages other than the one demanded by a page fault are brought in. The selection of such pages is done based on common access patterns, especially for secondary memory devices.
27.Paging a memory management function, while multiprogramming a processor management function, are the two interdependent?
Yes.
28.What is page cannibalizing?
Page swapping or page replacements are called page cannibalizing.
29.What has triggered the need for multitasking in PCs?
Increased speed and memory capacity of microprocessors together with the support fir virtual memory and
Growth of client server computing
30.What are the four layers that Windows NT have in order to achieve independence?
Hardware abstraction layer
Kernel
Subsystems
System Services.
31.What is SMP?
To achieve maximum efficiency and reliability a mode of operation known as symmetric multiprocessing is used. In essence, with SMP any process or threads can be assigned to any processor.
32.What are the key object oriented concepts used by Windows NT?
Encapsulation
Object class and instance
33.Is Windows NT a full blown object oriented operating system? Give reasons.
No Windows NT is not so, because its not implemented in object oriented language and the data structures reside within one executive component and are not represented as objects and it does not support object oriented capabilities .
34.What is a drawback of MVT?
It does not have the features like
ability to support multiple processors
virtual storage
source level debugging
35.What is process spawning?
When the OS at the explicit request of another process creates a process, this action is called process spawning.
36.How many jobs can be run concurrently on MVT?
15 jobs
37.List out some reasons for process termination.
Normal completion
Time limit exceeded
Memory unavailable
Bounds violation
Protection error
Arithmetic error
Time overrun
I/O failure
Invalid instruction
Privileged instruction
Data misuse
Operator or OS intervention
Parent termination.
38.What are the reasons for process suspension?
swapping
interactive user request
timing
parent process request
39.What is process migration?
It is the transfer of sufficient amount of the state of process from one machine to the target machine
40.What is mutant?
In Windows NT a mutant provides kernel mode or user mode mutual exclusion with the notion of ownership.
41.What is an idle thread?
The special thread a dispatcher will execute when no ready thread is found.
42.What is FtDisk?
It is a fault tolerance disk driver for Windows NT.
43.What are the possible threads a thread can have?
Ready
Standby
Running
Waiting
Transition
Terminated.
44.What are rings in Windows NT?
Windows NT uses protection mechanism called rings provides by the process to implement separation between the user mode and kernel mode.
45.What is Executive in Windows NT?
In Windows NT, executive refers to the operating system code that runs in kernel mode.
46.What are the sub-components of I/O manager in Windows NT?
Network redirector/ Server
Cache manager.
File systems
Network driver
Device driver
47.What are DDks? Name an operating system that includes this feature.
DDks are device driver kits, which are equivalent to SDKs for writing device drivers. Windows NT includes DDks.
48.What level of security does Windows NT meets?
C2 level security.
Long term scheduler determines which programs are admitted to the system for processing. It controls the degree of multiprogramming. Once admitted, a job becomes a process.
Medium term scheduling is part of the swapping function. This relates to processes that are in a blocked or suspended state. They are swapped out of real-memory until they are ready to execute. The swapping-in decision is based on memory-management criteria.
Short term scheduler, also know as a dispatcher executes most frequently, and makes the finest-grained decision of which process should execute next. This scheduler is invoked whenever an event occurs. It may lead to interruption of one process by preemption.
7.What are turnaround time and response time?
Turnaround time is the interval between the submission of a job and its completion. Response time is the interval between submission of a request, and the first response to that request.
8.What are the typical elements of a process image?
User data: Modifiable part of user space. May include program data, user stack area, and programs that may be modified.
User program: The instructions to be executed.
System Stack: Each process has one or more LIFO stacks associated with it. Used to store parameters and calling addresses for procedure and system calls.
Process control Block (PCB): Info needed by the OS to control processes.
9.What is the Translation Lookaside Buffer (TLB)?
In a cached system, the base addresses of the last few referenced pages is maintained in registers called the TLB that aids in faster lookup. TLB contains those page-table entries that have been most recently used. Normally, each virtual memory reference causes 2 physical memory accesses-- one to fetch appropriate page-table entry, and one to fetch the desired data. Using TLB in-between, this is reduced to just one physical memory access in cases of TLB-hit.
10.What is the resident set and working set of a process?
Resident set is that portion of the process image that is actually in real-memory at a particular instant. Working set is that subset of resident set that is actually needed for execution. (Relate this to the variable-window size method for swapping techniques.)
11.When is a system in safe state?
The set of dispatchable processes is in a safe state if there exists at least one temporal order in which all processes can be run to completion without resulting in a deadlock.
12.What is cycle stealing?
We encounter cycle stealing in the context of Direct Memory Access (DMA). Either the DMA controller can use the data bus when the CPU does not need it, or it may force the CPU to temporarily suspend operation. The latter technique is called cycle stealing. Note that cycle stealing can be done only at specific break points in an instruction cycle.
13.What is meant by arm-stickiness?
If one or a few processes have a high access rate to data on one track of a storage disk, then they may monopolize the device by repeated requests to that track. This generally happens with most common device scheduling algorithms (LIFO, SSTF, C-SCAN, etc). High-density multisurface disks are more likely to be affected by this than low density ones.
14.What are the stipulations of C2 level security?
C2 level security provides for:
Discretionary Access Control
Identification and Authentication
Auditing
Resource reuse
15.What is busy waiting?
The repeated execution of a loop of code while waiting for an event to occur is called busy-waiting. The CPU is not engaged in any real productive activity during this period, and the process does not progress toward completion.
16.Explain the popular multiprocessor thread-scheduling strategies.
Load Sharing: Processes are not assigned to a particular processor. A global queue of threads is maintained. Each processor, when idle, selects a thread from this queue. Note that load balancing refers to a scheme where work is allocated to processors on a more permanent basis.
Gang Scheduling: A set of related threads is scheduled to run on a set of processors at the same time, on a 1-to-1 basis. Closely related threads / processes may be scheduled this way to reduce synchronization blocking, and minimize process switching. Group scheduling predated this strategy.
Dedicated processor assignment: Provides implicit scheduling defined by assignment of threads to processors. For the duration of program execution, each program is allocated a set of processors equal in number to the number of threads in the program. Processors are chosen from the available pool.
Dynamic scheduling: The number of thread in a program can be altered during the course of execution.
17.When does the condition 'rendezvous' arise?
In message passing, it is the condition in which, both, the sender and receiver are blocked until the message is delivered.
18.What is a trap and trapdoor?
Trapdoor is a secret undocumented entry point into a program used to grant access without normal methods of access authentication. A trap is a software interrupt, usually the result of an error condition.
19.What are local and global page replacements?
Local replacement means that an incoming page is brought in only to the relevant process' address space. Global replacement policy allows any page frame from any process to be replaced. The latter is applicable to variable partitions model only.
20.Define latency, transfer and seek time with respect to disk I/O.
Seek time is the time required to move the disk arm to the required track. Rotational delay or latency is the time it takes for the beginning of the required sector to reach the head. Sum of seek time (if any) and latency is the access time. Time taken to actually transfer a span of data is transfer time.
21.Describe the Buddy system of memory allocation.
Free memory is maintained in linked lists, each of equal sized blocks. Any such block is of size 2^k. When some memory is required by a process, the block size of next higher order is chosen, and broken into two. Note that the two such pieces differ in address only in their kth bit. Such pieces are called buddies. When any used block is freed, the OS checks to see if its buddy is also free. If so, it is rejoined, and put into the original free-block linked-list.
22.What is time-stamping?
It is a technique proposed by Lamport, used to order events in a distributed system without the use of clocks. This scheme is intended to order events consisting of the transmission of messages. Each system 'i' in the network maintains a counter Ci. Every time a system transmits a message, it increments its counter by 1 and attaches the time-stamp Ti to the message. When a message is received, the receiving system 'j' sets its counter Cj to 1 more than the maximum of its current value and the incoming time-stamp Ti. At each site, the ordering of messages is determined by the following rules: For messages x from site i and y from site j, x precedes y if one of the following conditions holds....(a) if Ti
23.How are the wait/signal operations for monitor different from those for semaphores?
If a process in a monitor signal and no task is waiting on the condition variable, the signal is lost. So this allows easier program design. Whereas in semaphores, every operation affects the value of the semaphore, so the wait and signal operations should be perfectly balanced in the program.
24.In the context of memory management, what are placement and replacement algorithms?
Placement algorithms determine where in available real-memory to load a program. Common methods are first-fit, next-fit, best-fit. Replacement algorithms are used when memory is full, and one process (or part of a process) needs to be swapped out to accommodate a new program. The replacement algorithm determines which are the partitions to be swapped out.
25.In loading programs into memory, what is the difference between load-time dynamic linking and run-time dynamic linking?
For load-time dynamic linking: Load module to be loaded is read into memory. Any reference to a target external module causes that module to be loaded and the references are updated to a relative address from the start base address of the application module.
With run-time dynamic loading: Some of the linking is postponed until actual reference during execution. Then the correct module is loaded and linked.
26.What are demand- and pre-paging?
With demand paging, a page is brought into memory only when a location on that page is actually referenced during execution. With pre-paging, pages other than the one demanded by a page fault are brought in. The selection of such pages is done based on common access patterns, especially for secondary memory devices.
27.Paging a memory management function, while multiprogramming a processor management function, are the two interdependent?
Yes.
28.What is page cannibalizing?
Page swapping or page replacements are called page cannibalizing.
29.What has triggered the need for multitasking in PCs?
Increased speed and memory capacity of microprocessors together with the support fir virtual memory and
Growth of client server computing
30.What are the four layers that Windows NT have in order to achieve independence?
Hardware abstraction layer
Kernel
Subsystems
System Services.
31.What is SMP?
To achieve maximum efficiency and reliability a mode of operation known as symmetric multiprocessing is used. In essence, with SMP any process or threads can be assigned to any processor.
32.What are the key object oriented concepts used by Windows NT?
Encapsulation
Object class and instance
33.Is Windows NT a full blown object oriented operating system? Give reasons.
No Windows NT is not so, because its not implemented in object oriented language and the data structures reside within one executive component and are not represented as objects and it does not support object oriented capabilities .
34.What is a drawback of MVT?
It does not have the features like
ability to support multiple processors
virtual storage
source level debugging
35.What is process spawning?
When the OS at the explicit request of another process creates a process, this action is called process spawning.
36.How many jobs can be run concurrently on MVT?
15 jobs
37.List out some reasons for process termination.
Normal completion
Time limit exceeded
Memory unavailable
Bounds violation
Protection error
Arithmetic error
Time overrun
I/O failure
Invalid instruction
Privileged instruction
Data misuse
Operator or OS intervention
Parent termination.
38.What are the reasons for process suspension?
swapping
interactive user request
timing
parent process request
39.What is process migration?
It is the transfer of sufficient amount of the state of process from one machine to the target machine
40.What is mutant?
In Windows NT a mutant provides kernel mode or user mode mutual exclusion with the notion of ownership.
41.What is an idle thread?
The special thread a dispatcher will execute when no ready thread is found.
42.What is FtDisk?
It is a fault tolerance disk driver for Windows NT.
43.What are the possible threads a thread can have?
Ready
Standby
Running
Waiting
Transition
Terminated.
44.What are rings in Windows NT?
Windows NT uses protection mechanism called rings provides by the process to implement separation between the user mode and kernel mode.
45.What is Executive in Windows NT?
In Windows NT, executive refers to the operating system code that runs in kernel mode.
46.What are the sub-components of I/O manager in Windows NT?
Network redirector/ Server
Cache manager.
File systems
Network driver
Device driver
47.What are DDks? Name an operating system that includes this feature.
DDks are device driver kits, which are equivalent to SDKs for writing device drivers. Windows NT includes DDks.
48.What level of security does Windows NT meets?
C2 level security.
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