I am a first year computer science student. Being a computer science student I was interested in knowing the difference between absolute loader and relocating loader.Please explain with examples.
An absolute loader is the most basic type of loading technique which loads the file into memory at the location determined by the header of the file, after that it passes control to the user program.
A relocatable loader, on the contrary, loads the user’s program anywhere in memory as defined by the user or my memory logic. This leads to alteration of addresses which are required for correct referencing.
An absolute loader is the easiest or simplest type of loading scheme. In this method, the file is loaded at a specific location in the memory. The location is indicated at the beginning or header of the file then the control is passed on to the program. This is one of the two types of loaders and is the simplest and quickest of the two.
If the memory address or memory location indicated by the header is currently in use, the execution of the program cannot continue. The user has to wait until that memory address becomes free. The relocating loader is the second type of loader. In this scheme, the program is loaded anywhere in the memory and changing different addresses as needed to guarantee accurate referencing.
The operating system is the one handling the location of the program where to put it in the memory. This method is actually more effective but introduces a small overhead in terms of delay while all relative offsets are calculated.
