When a program tries to access a page that is mapped in address space but not loaded in physical memory, then ____________

In a paged memory, the page hit ratio is 0.35. The required to access a page in secondary memory is equal to 100 ns. The time required to access a page in primary memory is 10 ns. The average time required to access a page is?

A

3.0 ns

B

68.0 ns

C

68.5 ns

D

78.5 ns

The linear address space is mapped into the processors physical address space either directly or through paging by

A

flat memory model

B

segmented memory model

C

flat or segmented memory model

D

none

A linear Hamming code is used to map 4-bit messages to 7-bit codewords. The encoder mapping is linear. If the message 0001 is mapped to the codeword 0000111, and the message 0011 is mapped to the codeword 1100110, then the message 0010 is mapped to

A

0010011

B

1111111

C

1111000

D

1100001

If the size of logical address space is 2 to the power of m, and a page size is 2 to the power of n addressing units, then the high order _____ bits of a logical address designate the page number, and the ____ low order bits designate the page offset.

A

m, n

B

n, m

C

m – n, m

D

m – n, n

Which daemon manages the physical memory by moving process from physical memory to swap space when more physical memory is needed.

A

Sched daemon

B

Swap daemon

C

Init daemon

D

Process daemon

The maximum harbour depth below lowest low water is generally equal to
(i) loaded draft + 1.2 m when bottom is rock
(ii) loaded draft + 1.8 m when bottom is soft
(iii) loaded draft + 1.2 m when bottom is soft
(iv) loaded draft + 1.8 m when bottom is rock

A

(i) and (ii) are correct

B

(i) and (iii) are correct

C

(ii) and (iv) are correct

D

(iii) and (iv) are correct

A multilevel page table is preferred in comparison to a single level page table for translating virtual address to physical address because ____________

A

it reduces the memory access time to read or write a memory location

B

it helps to reduce the size of page table needed to implement the virtual address space of a process

C

it is required by the translation lookaside buffer

D

it helps to reduce the number of page faults in page replacement algorithms

Applying the LRU page replacement to the following reference string. 1 2 4 5 2 1 2 4 The main memory can accommodate 3 pages and it already has pages 1 and 2. Page 1 came in before page 2. How many page faults will occur?

A

2

B

3

C

4

D

5

The address loaded into the memory address register of the memory is referred to as ____________

A

Physical address

B

Logical address

C

Neither physical nor logical

D

None of the mentioned

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 ____________

A

p x ma + (1-p) x page fault time

B

ma + page fault time

C

(1-p) x ma + p x page fault time

D

none of the mentioned

When a program tries to access a page that is mapped in address space but not loaded in physical memory, then ____________

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