Operating System Set 18
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This set of Operating System (OS) Multiple Choice Questions & Answers (MCQs) focuses on Operating System Set 18
Q1 | Virtual memory allows
- execution of a process that may not be completely in memory
- a program to be smaller than the physical memory
- a program to be larger than the secondary storage
- execution of a process without being in physical memory
Q2 | A process is thrashing if
- it is spending more time paging than executing
- it is spending less time paging than executing
- page fault occurs
- swapping can not take place
Q3 | The ability to execute a program that is only partially in memory has benefits like
- the amount of physical memory cannot put a constraint on the program
- programs for an extremely large virtual space can be created
- throughput increases
- all of the mentioned
Q4 | Virtual memory is normally implemented by
- demand paging
- buses
- virtualization
- all of the mentioned
Q5 | Segment replacement algorithms are more complex than page replacement algorithms because
- segments are better than pages
- pages are better than segments
- segments have variable sizes
- segments have fixed sizes
Q6 | A swapper manipulates whereas the pager is concerned with individual of a process.
- the entire process, parts
- all the pages of a process, segments
- the entire process, pages
- none of the mentioned
Q7 | Using a pager
- increases the swap time
- decreases the swap time
- decreases the swap time & amount of physical memory needed
- increases the amount of physical memory needed
Q8 | The valid – invalid bit, in this case, when valid indicates?
- the page is not legal
- the page is illegal
- the page is in memory
- the page is not in memory
Q9 | A page fault occurs when?
- a page gives inconsistent data
- a page cannot be accessed due to its absence from memory
- a page is invisible
- all of the mentioned
Q10 | When a page fault occurs, the state of the interrupted process is
- disrupted
- invalid
- saved
- none of the mentioned
Q11 | When a process begins execution with no pages in memory?
- process execution becomes impossible
- a page fault occurs for every page brought into memory
- process causes system crash
- none of the mentioned
Q12 | If the memory access time is denoted by ‘ma’ and ‘p’ is the probability of a page fault (0 <= p <= 1). Then the effective access time for a demand paged memory is
- p x ma + (1-p) x page fault time
- ma + page fault time
- (1-p) x ma + p x page fault time
- none of the mentioned
Q13 | When the page fault rate is low
- the turnaround time increases
- the effective access time increases
- the effective access time decreases
- turnaround time & effective access time increases
Q14 | Locality of reference implies that the page reference being made by a process
- will always be to the page used in the previous page reference
- is likely to be one of the pages used in the last few page references
- will always be one of the pages existing in memory
- will always lead to page faults
Q15 | Which of the following page replacement algorithms suffers from Belady’s Anomaly?
- optimal replacement
- lru
- fifo
- both optimal replacement and fifo
Q16 | In question 2, if the number of page frames is increased to 4, then the number of page transfers
- decreases
- increases
- remains the same
- none of the mentioned
Q17 | A memory page containing a heavily used variable that was initialized very early and is in constant use is removed, then the page replacement algorithm used is
- lru
- lfu
- fifo
- none of the mentioned
Q18 | Users that their processes are running on a paged system.
- are aware
- are unaware
- may unaware
- none of the mentioned
Q19 | If no frames are free, page transfer(s) is/are required.
- one
- two
- three
- four
Q20 | A FIFO replacement algorithm associates with each page the
- time it was brought into memory
- size of the page in memory
- page after and before it
- all of the mentioned
Q21 | What is the Optimal page – replacement algorithm?
- replace the page that has not been used for a long time
- replace the page that has been used for a long time
- replace the page that will not be used for a long time
- none of the mentioned
Q22 | LRU page – replacement algorithm associates with each page the
- time it was brought into memory
- the time of that page’s last use
- page after and before it
- all of the mentioned
Q23 | What are the two methods of the LRU page replacement policy that can be implemented in hardware?
- counters
- ram & registers
- stack & counters
- registers
Q24 | When using counters to implement LRU, we replace the page with the
- smallest time value
- largest time value
- greatest size
- none of the mentioned
Q25 | There is a set of page replacement algorithms that can never exhibit Belady’s Anomaly, called
- queue algorithms
- stack algorithms
- string algorithms
- none of the mentioned