Relocatable loading
Relocatable loading refers to a method of loading software or data into memory in a way that allows it to be relocated or moved to different memory locations without affecting its execution. This concept is commonly used in programming and computer systems to ensure flexibility and efficient memory utilization.
To understand how relocatable loading works, let's explore the basic steps involved:
1. Compilation: The first step is to compile the source code into object code. During this process, the compiler generates the machine code specific to the target system.
2. Object module generation: The object module is created by the linker, which combines the compiled object code with other necessary library modules. The linker resolves symbols and creates relocation tables.
3. Relocation: In this step, the relocation process examines the object module and determines the memory addresses where the code and data need to be loaded. The linker modifies the relocation tables to specify the locations of the symbols and the distance to be adjusted.
4. Loading: The loader is responsible for loading the executable code into memory. It uses the relocation tables to adjust the addresses for code and data based on the actual memory location where the program will be loaded.
By using relocatable loading techniques, a program can be loaded at any available memory location without requiring modifications to the code itself. This flexibility allows for more efficient memory usage and simplifies the process of running programs on different systems or in different memory configurations.
Relocatable loading is particularly useful in situations where memory addresses are not known at compile time or when multiple programs need to be loaded simultaneously and must be assigned separate memory regions.
Overall, relocatable loading contributes to the portability and versatility of software, enabling it to be executed efficiently across different platforms and memory configurations.