Computers

Difference Between Logical Address and Physical Address

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Main Difference

The main difference between the logical address and a physical address is that the logical address is the virtual address that is generated by the CPU, whereas the physical address is in the memory of the computer system.

Logical Address vs. Physical Address

In a computer system, the memory and registers are used to store data information. There are two types of registers naming logical and physical addresses, and each register is identified by its address. The logical address is an address that is generated during the program execution by the central processing unit (CPU). The physical address is in the memory of the computer system. The logical address can be seen by the users because it is a virtual address. The physical address cannot be seen by the users directly.

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The logical address is known as a reference in the computer. The logical address can be accessed directly, whereas the physical address is not directly accessible. The physical address is accessed by a logical address. The mapping is the most essential part because it maps logical addresses to the physical address. In the mapping, the memory management unit (MMU) plays an important part. A logical address deals with the users and a physical address execute the programs that are generated by the users.

The logical address is viewable, whereas the physical address is not viewable. A logical address gets erased when a system reboots, whereas it does not affect the physical address. The memory management unit generates an identical logical and physical address. Both addresses are generated during loading and compilation time. The different logical and physical addresses are generated by the address-binding method during its run time. The logical address changes from time to time and is variable, whereas the physical address is constant.

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Comparison Chart

Logical AddressPhysical Address
Definition
It is generated by the central processing unit.The physical address is in the memory of the computer system.
Logical/ Physical Address Space
A set of all logical addresses is known as logical address space, and it is generated by the central processing unit with program reference.Physical address space is a set of all physical addresses that are mapped with the correspondence of logical addresses.
Accessibility
The logical address is used to access the physical address.It is not directly accessible.
Variations
It is variable.It is constant.
Generated by
The central processing unit generates a logical address.The memory management unit generates a physical address.
Identification
It helps in obtaining the physical address.It helps in identifying a location in memory.
Visibility
The logical address is visible to the users.The physical address is not visible to the users.

What is a Logical Address?

The logical address is an address that is generated during the program execution by the central processing unit (CPU). It is a variable address that changes from time to time. A set of all logical addresses is known as logical address space, and it generates by the central processing unit with program reference. The logical address is used by the users to access the physical address. When a system is rebooted, its logical address is erased.

A logical address can also be viewed by the users because it is a virtual address. It is not physically available. This address deals with users. The logical address can be accessed directly and is also viewable. The logical address is known as a reference in the computer. In the mapping, the memory management unit (MMU) plays an important part because it maps logical addresses to the physical address.

What is a Physical Address?

The physical address is an address that locates in the memory of the computer system. The memory management unit generates a physical address. Physical address space is a set of all physical addresses that are mapped with the correspondence of logical addresses. The physical address cannot be seen by the users directly. Users can access the physical address through indirect methods. The physical address is accessed by a logical address.

It only executes the programs that are generated by the users. A program execution needs a physical address. It is not viewable. When a system is rebooted, it does not affect its physical address. The memory management unit generates an identical logical and physical address. Both addresses are generated during loading and compilation time. The different logical and physical addresses are generated by the address-binding method during its run time. Hence the physical address is constant, so it does not change.

Key Differences

  1. A logical address is a virtual address that is generated by the CPU, whereas a physical address is in the memory of the computer system.
  2. The logical address gets changed each time because it is a variable address; on the other hand, the physical address does not change.
  3. The logical address is visible to the users., whereas the physical address is restricted to access by the users.
  4. The logical address is viewable, whereas the physical address is not viewable by the users.
  5. The logical address is also known as the virtual address and does not exist physically, whereas a physical address can be accessed because it is a location in the memory.
  6. The logical address can be accessed directly, whereas the physical address is accessed through indirect methods.
  7. The logical address is a set of all logical addresses that are generated by the CPU about a program are known as logical address space, whereas the physical address is a set of all physical addresses that are mapped in corresponding with the logical addresses are known as physical address space.
  8. A logical address gets erased when a system reboots, whereas when a system is rebooted, it does not affect its physical address.
  9. Both logical and physical addresses are generated during loading and compilation time.

Conclusion

The memory management unit generates an identical logical and physical address. Both addresses are generated during loading and compilation time. The different logical and physical addresses are generated by the address-binding method during its run time.

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Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss