Additional Information. Virtual Memory consists of those addresses that may be generated by a processor during execution of a computation. The addresses in virtual memory are called logical addresses. These addresses are dynamically translated into physical addresses at run time. All the addresses may or may not be required for program execution at once.
Virtual memory:. Virtual memory is a feature of an operating system OS that enables a computer to be able to compensate for the shortage of physical memory by transferring a page of data from RAM to disk storage. Advantage of virtual memory:. Option 3 correct. Important Points. More information:. Swap-in: Higher priority process can be swapped-in from the disk to the main memory with a lower priority process. Swap-out: Lower priority process from memory can be swapped out so that a higher priority process can be executed.
To free user programs from the need to carry out storage allocation and to permit efficient sharing of the available memory space among different users. To make program independent of the configuration and capacity of the physical memory for their execution. To achieve the very low access time and cost per bit that is possible with a memory hierarchy. It is a mechanism in which a process can be swapped temporarily out of main memory or move to secondary storage disk and make that memory available to other processes.
At some later time, the system swaps back the process from the secondary storage to main memory. Arnab Chakraborty.
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Java Wrapper Class. Explanation: There are two types of principle of locality Spatial locality: whenever we are looking for an element the chances are that, the particular element will be present in a close proximity around the one which we have previously referred. Temporal locality: Least recently used element is going to be used again. Principle of locality is the correct answer, hence option 3 is the correct answer.
Answer Detailed Solution Below Option 2 : 8. Get Started for Free Download App. Also, LRU Is a stack algorithm. A stack algorithm is one that satisfies the inclusion property. Belady's anomaly may occur in FIFO Key Points A page fault occurs when a page is not found in the memory and needs to be loaded from the disk.
If a page fault occurs and all memory frames have been already allocated, then the replacement of a page in memory is required at the request of a new page. This is referred to as demand-paging. The choice of which page to replace is specified by a page replacement algorithm. Sometimes the reverse happens, that is, more numbers of page faults occur when more frames are allocated to a process.
Concept: Demand paging allows the execution of programs large than the size of physical memory. Important Points about demand paging: It combines the features of simple paging and overlaying to implement virtual memory. Each page of the program is stored contiguously in the paging swap space on secondary storage. Once the page is in the memory, it is accessed as in simple paging. Some form of hardware support is required to distinguish between those pages that are in memory and those are on the disk.
Valid and invalid bits are used for this. Answer Detailed Solution Below In this, we either have to only fetch the page 0. Answer Detailed Solution Below Option 2 : page replacement. A page fault occurs when a page is not found in the memory and needs to be loaded from the disk. Hence Belady's anomaly may occur in page replacement. Answer Detailed Solution Below Option 2 : Answer Detailed Solution Below Option 1 : Concept: In the First In First Out FIFO algorithm, the operating system keeps track of all pages in the memory in a queue, the oldest page is in the front of the queue.
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