In memory management, what is meant by the logical address space and the physical address space of a process?

Introduction / Context:
Memory management in modern operating systems often uses an extra level of indirection between the addresses used by programs and the actual locations in hardware memory. Understanding the distinction between logical and physical address spaces is essential for topics such as virtual memory, paging and relocation, and helps explain how processes are isolated from each other.

Given Data / Assumptions:

A process executes instructions that reference memory locations through addresses.
The CPU initially works with addresses produced by the program, which may not be the same as the final hardware addresses.
A memory management unit can translate addresses at run time.
The question asks for definitions of logical and physical address spaces.

Concept / Approach:
The logical address space, sometimes called the virtual address space, is the range of addresses that a process can generate during execution. These addresses are meaningful to the process and are used in its instructions. The physical address space refers to the set of real locations in main memory. The memory management unit, controlled by the operating system, maps logical addresses to physical addresses. This mapping allows each process to have its own logical view of memory while sharing the same physical memory safely.

Step-by-Step Solution:
Step 1: When a process executes an instruction like load value from address X, the CPU uses the logical address X as part of the instruction. Step 2: In systems with virtual memory, this logical address is sent to the memory management unit rather than directly to the memory hardware. Step 3: The memory management unit consults page tables or segment tables to translate the logical address into a corresponding physical address in RAM. Step 4: The physical address is what actually appears on the address bus and selects a location in main memory chips. Step 5: The collection of all possible logical addresses a process may use is its logical address space, and the collection of all hardware addresses the system can use is the physical address space.

Verification / Alternative check:
Operating system literature defines logical addresses as program generated addresses before mapping and physical addresses as addresses seen by the memory hardware after mapping. The terms are not defined in terms of stack versus heap, disk versus cache or fixed numeric sizes, which confirms that the correct option focuses on generated versus actual memory addresses.

Why Other Options Are Wrong:
Both logical and physical addresses usually refer to main memory, even though virtual memory may extend logical addresses to disk; disk is not itself the logical address space.
Logical and physical address spaces encompass all parts of the process memory, including code, data, heap and stack, not only one region.
Their sizes depend on architecture and configuration; they are not universally tied to specific values like one kilobyte or one gigabyte.

Common Pitfalls:
Learners sometimes think that logical addresses exist only on disk and physical addresses only in RAM, which oversimplifies virtual memory. Another pitfall is to forget that each process may have its own logical address space that maps into different parts of a shared physical address space, which is how protection and isolation are achieved.

Final Answer:
The logical address space is the set of addresses generated by the CPU and used by a process in its instructions, while the physical address space is the set of actual hardware memory locations in main memory where data and instructions are stored.