In computer operating systems, demand paging (as opposed to anticipatory paging) is a method of virtual memory management. In a system that uses demand paging, the operating system copies a disk page into physical memory only if an attempt is made to access it and that page is not already in memory (i.e., if a page fault occurs). It follows that a process begins execution with none of its pages in physical memory, and many page faults will occur until most of a process's working set of pages are located in physical memory. This is an example of a lazy loading technique. Show
Basic concept[edit]Demand paging follows that pages should only be brought into memory if the executing process demands them. This is often referred to as lazy evaluation as only those pages demanded by the process are swapped from secondary storage to main memory. Contrast this to pure swapping, where all memory for a process is swapped from secondary storage to main memory during the process startup. Commonly, to achieve this process a page table implementation is used. The page table maps logical memory to physical memory. The page table uses a bitwise operator to mark if a page is valid or invalid. A valid page is one that currently resides in main memory. An invalid page is one that currently resides in secondary memory. When a process tries to access a page, the following steps are generally followed:
Advantages[edit]Demand paging, as opposed to loading all pages immediately:
Disadvantages[edit]
See also[edit]Wikisource has original text related to this article:
References[edit]
Home » Undergraduate study » Module 9: Operating Systems She asks you what types of program are Safari and Edge. You tell her that these are . When describing the macOS interface, you tell her that she can use the to view,
organize, and run apps.
Answer: False Answer: False Answer: restart
Answer: False
Answer: True Answer: True Answer: True
You learn that if you replace your printer with a new one, you will have to install a(n) to your computer.
Answer: administrator
Answer: False Answer: Backward
Answer: voice Answer: True
Answer: graphical
Answer: operating
Answer: False
Answer: Linux
Answer: False
Answer: True Answer: False Answer: False
You learn that by spooling documents to a(n) , the computer or mobile device can continue interpreting and executing instructions while the printer prints.
Answer: True
Answer: True Answer: True Answer: buffer When an operating system spends much of its time paging It is said to be quizlet?When an operating system spends much of its time paging, instead of executing application software, it is said to be thrashing. A buffer is a segment of memory or storage in which items are placed while waiting to be transferred from an input device or to an output device. 4) Define the terms, user interface.
What is it called when a computer runs more than one process at a time quizlet?Multiprogramming is the ability to run multiple jobs on a single system at the same time. This technique uses memory to store data/instructions in a "queue" that the CPU will process.. This allows the CPU (traditionally a very expensive component) to not be idle for extended periods of time.
When you purchase a computer or mobile device is it usually has an operating system and other tools installed True or false?When you purchase a computer or mobile device, it usually has an operating system and other tools installed. Some operating systems allow users to control a network and administer security. Not all computer and mobile devices have an operating system.
What happens when the computer is thrashing?In computer science, thrashing occurs when a computer's virtual memory resources are overused, leading to a constant state of paging and page faults, inhibiting most application-level processing. This causes the performance of the computer to degrade or collapse.
|