difference between logical and physical address

The Difference Between Logical and Physical Address

When it comes to understanding how computer systems manage memory and store data, it’s important to distinguish between logical and physical address. These two concepts relate to how information is organized and accessed within a computer’s memory hierarchy.

The Logical Address

A logical address refers to the way in which a computer application or program identifies a specific piece of data. This address is assigned by the CPU and is typically managed by the operating system. It represents a virtual address that allows the software to access memory locations without knowing the physical location of those locations.

Imagine that you have an application that wants to store a file on your computer’s hard drive. The file will have a logical address that serves as a kind of label to help the operating system locate the data. The logical address might be something like “/home/user/documents/myfile.txt”. This address is not tied to any specific location in memory, but is simply a way of identifying where the desired file is stored.

The Physical Address

In contrast to the logical address, the physical address refers to the actual location of data within a computer’s memory hierarchy. This address is assigned by the hardware of the computer, typically via the memory controller. It represents the physical location of a piece of data within RAM or other storage devices.

When the operating system needs to access a specific piece of data, it will translate the logical address into a physical address by using a hardware component called the memory management unit (MMU). The MMU will map the logical address to a corresponding physical address, allowing the CPU to access the data at that location.

The Relationship Between Logical and Physical Address

While logical and physical addresses are distinct concepts, they are closely related. The logical address provides a way of identifying data without requiring knowledge of its specific location in memory. The physical address, on the other hand, represents the real location of data within the computer’s memory hierarchy.

When a program attempts to access a specific piece of data, it uses the logical address to ask the operating system to retrieve it. The operating system then uses the MMU to translate this logical address into a physical address. This process allows the CPU to access the data in a way that is transparent to the programmer.

Conclusion

Understanding the difference between logical and physical addresses is important for anyone who wants to work with computer systems. By knowing how these addresses work, you can better understand how data is stored and accessed within RAM and other storage devices. Whether you’re a software developer, IT professional, or simply a curious computer user, mastering these concepts can help you build a deeper understanding of how computer systems function.

Table difference between logical and physical address