Virtual memory, Operating System

Assignment Help:

In modern operating systems, applications do not directly access the physical memory. Instead, they use so-called virtual memory, where each virtual address is translated to a physical address. Why would one do this? Here are some of the reasons that virtual memory is useful:

 To isolate and protect processes from each other,

 To manage the limited physical memory ef?ciently,


To give each process the illusion of having the whole address space for itself.

Since each program thinks it has the whole memory to itself, programs can use a lot of virtual memory. In fact, a computer might use huge amounts of virtual memory, much more than the amount of actual physical memory available. Most of the time this works fairly well, since processes typically only need to use a small amount of their virtual memory at once, and often a lot can be shared among processes (such as with shared libraries). But if the system gets into a situation where the active virtual memory demands exceed the available physical memory, we will need to use another mechanism, such as "swapping" memory pages to disk.

Virtual memory uses one level of indirection in the translation from virtual addresses to physical addresses.


Related Discussions:- Virtual memory

Essential properties of operating system, Essential Properties of Operating...

Essential Properties of Operating System 1. Batch: Jobs with similar needs are batched together and run through the computer as a group by an operator or automatic job sequen

What is independent process, What is independent process? A process is ...

What is independent process? A process is independent it cannot influence or be affected by the other processes implementing in the system. Any process does not share data with

System service program, System Service Program system service program S...

System Service Program system service program Supports and provides the services for other program. System service program perform Varity of tasks.  They are further divided in

Explain the scheduleworktodo function used in netware, Explain the Schedule...

Explain the ScheduleWorkToDo Function used in Netware ScheduleWorkToDo(MyThread Function, arg, workToDo) The ScheduleWorkToDo ( ) function is specific to NetWare 4.0. This c

Operating system abstractions, When we download a movie from the Internet, ...

When we download a movie from the Internet, we don't care about, say, packet sizes. However, even ifwe are not aware of howlow-level details of networks are implemented, our data i

What is busy waiting?, What is busy waiting? When strict alteration is ...

What is busy waiting? When strict alteration is done there may take place situation like two processes setting their flag as true. Therefore both of the processes have equal pr

Explain the fork-join, Explain the Fork-join This is primitives in a hi...

Explain the Fork-join This is primitives in a higher level programming language for implementing interacting processes. The syntax is like this: fork ; join ; where

Custom memory allocation, Some people write custom memory allocators to mee...

Some people write custom memory allocators to meet their speci?c needs. Although this is not needed for most of the applications, it is also not uncommon. The goal, of course, is t

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd