An address space in computing is a range of discrete addresses (numerical values) that a program, a process, or an operating system can use to access and manage memory.
- It allows each program or process to use a set of memory addresses independently of other processes, even if they are sharing the same physical memory.
- Address spaces help in maintaining memory security and integrity by ensuring each process has access to only its allocated memory.
Types of Address Spaces
Address spaces in computer systems can be primarily classified into two types:
- Logical Address Space
- Physical Address Space
1.) Logical Address Space:
The logical address space, also known as the virtual address space, is the set of addresses that a program uses to access memory.
- These addresses are generated by the CPU during program execution and are not the actual physical addresses in memory.
- It is virtual as it does not exist physically.
• They are used to create an abstraction of memory, making it easier for programs to access memory without needing to know the actual physical locations. This is particularly useful in systems with virtual memory, where programs can utilize more memory than is physically available on the system.
Features:
- Created by the CPU and the operating system.
- Helps in isolating programs from each other, enhancing security and stability.
- Allows multiple programs to run simultaneously without interfering with each other’s memory space.
Physical Address Space
The physical address space is the set of all actual addresses in the computer’s RAM. It refers to the real locations in the memory hardware where data is stored and retrieved.
• Physical addresses are used by the hardware to store data in and retrieve it from RAM. When a program needs to read or write to memory, the logical address must be translated to a physical address to locate the actual data.
Features:
- Represents the actual memory available in the computer.
- Managed by the hardware and the operating system, which translates logical addresses to physical addresses.
- Limited to the total size of the installed RAM.
Comparison Logical vs Physical Address Spaces:
