Address is used to uniquely identify the location of something inside the CPU memory. These addresses are divided into two major types, the first being the logical address and the other, physical address. Both having different but somewhat similar functionality. The logical address serves as a virtual address which is viewable by the user program. The Physical address, however, is not viewable directly by the user program and the logical address is utilized as a resource to access the physical address with the aid of a pointer.
A logical address is also generated by a Central Processing Unit when a program is being executed whereas a physical address is an actual location found within the memory unit. When a logical address is mapped to its corresponding physical address, it becomes a joint a memory management unit between the CPU and the bus that carries the memory since the tasks performed are similar when it gets to the address translation layer and the CPU.
The best way to define such a layer that is created is a data link layer that serves as a connector between the hardware and software of the whole computer network. Address of something generated by the central processing unit while a program is running is referred to as a Logical Address. The address is also referred to as a virtual address. This is because it is used as a guideline for the architecture to understand where other things are positioned as it does not stay in the system hence variable.
A program that helps in finding the base address is required by the computer in order to find other locations within the system hence the logical address. Another way of understanding the operations of the logical address is a memory block that is used in the beginning within the system. It is combines with a base address to form a physical address that becomes a variant from other kinds of address due to the mapping translator.
What maps the logical address to its correlating physical address is the memory management unit. Load time and Compile-time address binding methods are used to create identical logical address and physical address while run time address binding produces a different logical and physical address. Logical addresses usually range from zero to maximum 0 to max. This is because the user program that generates a logical address assumes that the process runs in locations 0 to max. However, for a logical address to be used, it must be mapped onto a physical address.
Another important fact to note is that the logical memory gets erased in the event the system is rebooted making the information collected variable with time. Physical Address is used to identify a physical location within the memory management unit which computes according to the correlating logical address. This address is not directly accessible or viewed by the user program hence a logical address needs to be mapped to it to make it accessible with the aid of pointers which reveal location but not the code.
Sets of all corresponding physical addresses existing within the logical address are called physical address space. When a valid address is utilized as a memory address, it is moved on the base enlist where the memory administration unit changes over sensible locations into physical locations.
Address-restricting strategies, gathering time and load-time create Intelligent and physical locations. Points: 1. Points: 7. To understand the differences between these two addresses we first have to know what these addresses are and what they do. Physical address : It is an address of a memory location. When some data is stored in that memory location that data is said to be in that physical address.
Logical address : It is the address that the CPU assigns to a piece of data and can be mapped to the actual physical address of the data by certain mapping algorithms. Suppose for example a variable is stored in the memory location F physical. The logical address for this variable , say , is So whenever a process tries to access this variable it tries to access the logical address In the mapping scheme is pre-mapped to the physical address F Hence a query with the logical address returns the value from the physical address successfully.
Why logical and physical address levels are used : There are some reasons behind the concept of this two level addressing.
Memory allocation is a tricky business and many efficient memory allocation algorithms result in inconsistent and fractioned allocations so two pieces of data which should be placed together logically but due to memory optimization they have to be placed in remote corners of the available memory. In that case storing the addresses in the processors while executing relevant processes can create considerable overhead.
It is better to use logically sequenced addresses in the processor and map them to the physical counterparts elsewhere. So that's how logical and physical addresses are different and how they work. Hope you found them useful. Points: 8.
Hello friends, let us see the difference in detail. This address is burnt in the network Adapter called NIC card. This is a 48 bit address represented in hexadecimal format. Logical Address is generated by CPU while a program is running.
The logical address is virtual address as it does not exist physically, therefore, it is also known as Virtual Address. This address is used as a reference to access the physical memory location by CPU. The hardware device called Memory-Management Unit is used for mapping logical address to its corresponding physical address. Physical Address identifies a physical location of required data in a memory. The user never directly deals with the physical address but can access by its corresponding logical address.
The user program generates the logical address and thinks that the program is running in this logical address but the program needs physical memory for its execution, therefore, the logical address must be mapped to the physical address by MMU before they are used. The term Physical Address Space is used for all physical addresses corresponding to the logical addresses in a Logical address space.
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