Admin Table of Contents
- 1 What would happen if there were no virtual memory?
- 2 Can a computer run without virtual memory?
- 3 What happens if the process tries to access a page that was not brought into memory?
- 4 What problems would we face if there was no virtual memory in operating system?
- 5 Why virtual memory is needed?
- 6 When a program tries to access a page that is mapped in address space but not loaded in physical memory?
- 7 Where does virtual memory exist?
- 8 What is the relation between RAM address and virtual memory address?
- 9 What is the advantage of virtual memory over physical memory?
What would happen if there were no virtual memory?
If there were no such thing as virtual memory, then once you filled up the available RAM your computer would have to say, “Sorry, you can not load any more applications. When it is not the case, the operating system has to constantly swap information back and forth between RAM and the hard disk.
Can a computer run without virtual memory?
it is possible to run without virtual memory at all, just physical memory (in fact, most embedded systems run this way).
Can virtual memory work without RAM?
Virtual memory enables a system to run larger applications or run more applications at the same time without running out of RAM. Specifically, the system can operate as if its total RAM resources were equal to the amount of physical RAM, plus the amount of virtual RAM.
What happens if the process tries to access a page that was not brought into memory?
The page-table entry for a page that is brought into memory is set as usual, but the page-table entry for a page that is not currently in memory is either simply marked invalid or contains the address of the page on disk. Marking a page invalid will have no effect if the process never attempts to access that page.
What problems would we face if there was no virtual memory in operating system?
The OS will start killing other processes to free up memory. (Linux, or Windows without a pagefile, do this.) The OS will kill the offending process. The memory allocation will simply fail, causing the process to crash sooner or later (not sure if any OS behaves like this).
What happens in the virtual memory?
The OS moves data from processes that are not immediately needed out of the RAM and stores them in virtual memory. It copies the data back into RAM when the process is needed again. Using virtual memory slows the computer down because copying to a hard disk takes much longer than reading and writing RAM.
Why virtual memory is needed?
The main advantage of virtual memory is that an OS can load programs larger than its physical memory. It makes an impression to the users that the computer has unlimited memory. It also provides memory protection. In order to realize the mapping operations, virtual memory needs to use page tables and translations.
When a program tries to access a page that is mapped in address space but not loaded in physical memory?
page fault occurs is the correct answer to the given question. Explanation: The page fault arises when a code or the program tries to reach a storage block or the address space which is not located in the physical memory.
Why it is necessary that certain pages should not be paged out from main memory?
9.2. Even if only one access in 1000 causes a page fault, the effective access time drops from 200 nanoseconds to 8.2 microseconds, a slowdown of a factor of 40 times. In order to keep the slowdown less than 10%, the page fault rate must be less than 0.0000025, or one in 399,990 accesses.
Where does virtual memory exist?
Where does virtual memory exists? The reason why virtual memory is called virtual is it doesn’t exist! But its conceptual meaning is crucial when talking about memory. Every piece of instruction reference variable using address, which, is virtual address.
What is the relation between RAM address and virtual memory address?
Without the virtual memory program address directly map to the RAM addresses that means there is one to one relation exist between the program and ram memory addresses.
How does the virtual memory manager of the operating system work?
The virtual memory manager of the operating system applies a method called Paging to map the virtual address space to the physical address space, in such a way that all processes can get to run on the physical memory.
What is the advantage of virtual memory over physical memory?
It makes the physical memory appear limitless from the programmer’s view. When the RAM (main memory) is filled the virtual memory is used. Virtual memory is comparatively slower than the physical memory and it can decrease the performance of the CPU.