In this tutorial, we will be covering the principle of logical and also physical deal with space.

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The address that is created by the CPU is generally referred to together the Logical Address. The is basically a online address. The logical address is basically the address of an accuse or data used by any kind of program.

The collection of every logical addresses that are generated by any type of program is described as Logical resolve Space.

The attend to that is loaded into the memory-address register of the memory is typically referred to together a Physical address. A physical deal with cannot it is in accessed through the user directly however the user have the right to calculate the physical attend to with the aid of a Logical address.

The user"s program mainly generates the logical resolve and the user thinks the the routine is to run in this logical deal with but the program greatly needs physical memory in bespeak to finish its execution.

The set of all physics addresses corresponding to the logical addresses is typically known as Physical attend to Space.

Memory administration Unit(MMU) in OS

It is a hardware maker that go the run-time mapping native the virtual resolve to the physics address. The is located within the central Processing Unit.

Let us recognize the principle of mapping v the help of a straightforward MMU scheme and also that is a base-register scheme.


In the over diagram, the base register is termed the Relocation register. The relocation it is registered is a unique register in the CPU and is provided for the mapping of logical addresses used by a routine to physical addresses the the system"s key memory.

The worth in the relocation it is registered is included to every deal with that is created by the user process at the time as soon as the resolve is sent out to the memory.

MMU Example

Suppose the base is in ~ 14000, then an effort by the user to resolve location 0 is relocated dynamically to 14000; thus access to ar 356 is mapped come 14356.

It is important to keep in mind that the user program never ever sees the actual physical addresses. The regimen can develop a guideline to ar 356 and store that in the memory and also then manipulate it after the compare it with various other addresses together number 356.

User program constantly deals with the logical addresses. The Memory Mapping unit mainly converts the logical addresses into the physics addresses. The final location of the referenced memory address is no determined till the referral is made.

There space two types of addresses that we have:

logical addresses(lies in the selection 0 come max).

physical addresses(lies in the selection R+0 to R+max for the base worth R)

As we have told you above the user generates just a logical address and then thinks the the procedure runs in areas 0 to max. However, this logical addresses have to be mapped to physical addresses prior to they room used.

Difference between Logical deal with and physics Address

Let us currently cover the differences between the logical addresses and also Physical addresses in the operation System

S.NoLogical AddressPhysical Address1.
Users can accessibility the logical address that the Program.User have the right to never access the physical address that the Program
The logical address is generated by the CPU.The physical attend to is located in the storage unit.
The user can access the physical attend to with the help of a reasonable address.A physical resolve can be accessed through a user indirect b ut not directly.

The logical address does no exist physically in the memory and also thus termed together a digital address.

On the other hand, the physical address is a location in the memory. Therefore it deserve to be accessed physically.
The set of all logical addresses that are produced by any type of program is referred to as Logical attend to Space.The set of all physics addresses equivalent to the logical addresses is commonly known as Physical attend to Space.
This resolve is produced by the CPU.

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It is computed by the Memory monitoring Unit(MMU).