Q. Suppose there are six files F1, F2, F3, F4, F5, F6 with corresponding sizes 150 KB, 225KB, 75 KB, 60 KB, 275 KB and 65 KB respectively. The files are to be stored on a sequential device in such a way that optimizes access time. In what order should the files be stored?

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Q. Which module gives control of the CPU to the process selected by the short - term scheduler?

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Q. Two atomic operations permissible on Semaphores are .................. and ...............

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Q. Consider the following four schedules due to three transactions (indicated by the subscript) using read and write on a data item X, denoted by r(X) and w(X) respectively. Which one of them is conflict serializable?

S1 : r1(X); r2(X); w1(X); r3(X); w2(X)
S2 : r2(X); r1(X); w2(X); r3(X); w1(X)
S3 : r3(X); r2(X); r1(X); w2(X); w1(X)
S4 : r2(X); w2(X); r3(X); r1(X); w1(X)

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Q. Suppose a database schedule S involves transactions T1, T2, .............,Tn. Consider the precedence graph of S with vertices representing the transactions and edges representing the conflicts. If S is serializable, which one of the following orderings of the vertices of the precedence graph is guaranteed to yield a serial schedule?

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Q. Consider the following four processes with the arrival time and length of CPU burst given in milliseconds :

Process Arrival Time Burst Time
P1 0 8
P2 1 4
P3 2 9
P4 3 5

The average waiting time for preemptive SJF scheduling algorithm is .................

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Q. Consider a virtual page reference string 7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1, 7, 0, 1. Suppose a demand paged virtual memory system running on a computer system such that the main memory has 3 page frames. Then ................. page replacement algorithm has minimum number of page faults.

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Q. User level threads are threads that are visible to the programmer and are unknown to the kernel. The operating system kernel supports and manages kernel level threads. Three different types of models relate user and kernel level threads.

Which of the following statements is/are true?
(a) (i) The Many - to - one model maps many user threads to one kernel thread
(ii) The one - to - one model maps one user thread to one kernel thread
(iii) The many - to - many model maps many user threads to smaller or equal kernel threads

(b) (i) Many - to - one model maps many kernel threads to one user thread
(ii) One - to - one model maps one kernel thread to one user thread
(iii) Many - to - many model maps many kernel threads to smaller or equal user threads

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Q. Consider a disk queue with requests for I/O to blocks on cylinders 98, 183, 37, 122, 14, 124, 65, 67. Suppose SSTF disk scheduling algorithm implemented to meet the requests then the total number of head movements are ................... if the disk head is initially at 53.

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Q. The Bounded buffer problem is also known as ..................

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