Quiz 2
Question1
An executable program file is brought into memory and prepared for execution at:
Choose one answer.
a. Compile time.
b. Link time.
c. Load time.
d. Execution time.
e. None of the above.
Question2
Swapping of entire processes is:
Choose one answer.
a. Used as the primary CPU scheduling mechanismin most operating systems.
b. Efficient because it reduces disk input/output.
c. The basis for paging mechanisms.
d. The basis for segmentation mechanisms.
e. None of the above.
Question3
A consequence of main memory fragmentation is:
Choose one answer.
a. Inability to use sections of memory.
b. Gradual degradation of disk access performance due to rotational latency.
c. Excessively small programs.
d. Separation of programs into parts that may run in the same memory space
e. None of the above.
Question4
A contiguous allocation, variable partition size, physical memory system has holes (fragments of free space), in the indicated order, of size:
600K 700K 200K 500K 200K
Five processes of size:
500K 300K 500K 400K 200K
are to be placed in memory (in the indicated order) by the best-fit algorithm. The process that the algorithm will not place in memory is of size:
Choose one answer.
a. 500K
b. 400K
c. 300K
d. 200K
e. Best-fit will place all 5 processes in memory.
Question5
A contiguous allocation, variable partition size, physical memory system has holes (fragments of free space), in the indicated order, of size:
600K 700K 200K 500K 200K
Five processes of size:
500K 300K 500K 400K 200K
are to be placed in memory (in the indicated order) by the first-fit algorithm. The process that the algorithm will not place in memory is of size:
Choose one answer.
a. 500K
b. 400K
c. 300K
d. 200K
e. First-fit will place all 5 processes in memory.
Question6
Paging mechanisms suffer from:
Choose one answer.
a. Low performance when translation lookaside buffers are used.
b. Low performance when cached page tables are used.
c. Internal fragmentation.
d. External fragmentation.
e. None of the above.
Question7
Segmentation mechanisms suffer from:
Choose one answer.
a. Low performance when translation lookaside buffers are used.
b. Low performance when cached page tables are used.
c. Internal fragmentation
d. External fragmentation
e. None of the above.
Question8
A paged memory system uses pages of 100 bytes. A process' page table is:
0 16
1 03
2 00
3 01
4 05
The paging mechanism would translate the process' logical address 337 to:
Choose one answer.
a. 0337
b. 0037
c. 0137
d. 0338
e. None of the above
Question9
Which of the following mechanisms is NOT appropriate for implementation of page tables in a modern, large memory computer system architecture:
Choose one answer.
a. Multi-level
b. Single-Level
c. Hashed
d. Inverted
e. All of these mechanisms are appropriate.
Question10
Consider a demand-paged system where the memory access time is 50 nanoseconds when the requested page is a valid page in the page table, and the page-fault service time, on average, is 5 milliseconds. What is the highest acceptable page-fault rate, if the effective memory access time must not exceed 100 nanoseconds?
Choose one answer.
a. 1 fault per 100000 memory accesses.
b. 5 faults per 100000 memory accesses.
c. 10 faults per 100000 memory accesses.
d. 50 faults per 100000 memory accesses.
e. None of the above.
Question11
Marks: 5
Belady's anomaly:
Choose one answer.
a. Explains why LRU page replacement is not optimal.
b. Proves that there is no point in adding frames to a process that exhibits high page fault rates.
c. Applies to all page replacement algorithms
d. Is closely related to the "convoy effect".
e. None of the above.
Question12
Locality of reference:
Choose one answer.
a. Implies that memory references to an address tend to occur from instructions that are well-separated in address space.
b. Implies that memory references to an address tend to occur well-distributed over time.
c. Has an impact on page fault rates.
d. Is caused by self-modifying code.
e. None of the above.
Question13
The following description applies to questions: 13 and 14. In a system where paging is supported by a TLB (associative registers) cache, the CPU makes 9 consecutive memory accesses. The page numbers of the 9 logical addresses, in chronological order, are
9 8 4 5 9 6 4 7 5
The cache can hold a maximum of 4 page-table entries. The cache is initially empty.
When the cache is full, page-table entries enter and leave the cache in FIFO order. Calculate the hit-ratio of the cache for the given sequence of 9 logical addresses.
Choose one answer.
a. 1/3
b. 100%
c. 2/9
d. 5/9
e. None of the above
Question14
When the cache is full, page-table entries enter and leave the cache in LRU order. Calculate the hit-ratio of the cache for the given sequence of 9 logical addresses.
Choose one answer.
a. 1/3
b. 100%
c. 2/9
d. 5/9
e. None of the above
Question15
File name extensions are:
Choose one answer.
a. Limited to three characters.
b. Required in all operating systems to limit operations on a file.
c. Consistently applied across operating systems.
d. Fixed depending on the file contents.
e. None of the above.
Question16
Marks: 5
A file system uses linked allocation. A program has opened a file of 10 blocks so the file's file control block is in memory. How many disk input/output operations (read or write of a single block) are required to add a block to the middle of the file (between the 5th and 6th blocks)?
Choose one answer.
a. 1
b. 4
c. 6
d. 7
e. None of the above
Question17
The following description applies to questions: 17 and 18.
The read/write head of a disk drive is serving a request at track 100. The previous track accessed was 92. The queue of waiting requests holds requests for track numbers:
40 60 80 130 140
No other requests arrive before completing the 5 requests in the queue.
What is the total distance (number of tracks passed) the head travels to service all 5 requests using the SSTF algorithm?
Choose one answer.
a. 100
b. 140
c. 160
d. 180
e. None of the above
Question18
What is the total distance (number of tracks passed) the head travels to service all 5 requests using the C-LOOK algorithm?
Choose one answer.
a. 100
b. 140
c. 160
d. 180
e. None of the above
Question19
Which of the following is NOT a characteristic of RAID levels 1 through 6:
Choose one answer.
a. They improve disk input/output performance.
b. They improve the reliability of disk input/output operations.
c. They require some form of redundancy.
d. They reduce the likelihood of data loss.
e. All of the above are characteristics of RAID levels
1 through 6.
Question20
An advantage of a Storage Area Network over Network Attached Storage is:
Choose one answer.
a. Reduced latency between a client and a storage device.
b. Reduced latency between a server and a storage device.
c. Reduced latency between a server and a client.
d. The SAN can use lower cost LAN hardware.
e. None of the above