Difference between Absolute and Relocatable Loader

Difference between Absolute and Relocatable Loader

It is also known as boot loader or boot manager. The Loader 's task is to execute file in the Operating System that had been copied from the hard disk or any storage device to the primary memory. The first type is the Absolute Loader, this type is the simplest and most functional from the two. At the target selected by the header of the file, Loader stacks the file into memory, however if target's memory is in use, you need to hold it because execution will not be completed until it clears. While the other type is the Relocating Loader, that distributes a program or application in any position of the memory however, unlike Absolute Loader, Relocating Loader decides where it will be placed in the Operating System.

Difference between Absolute and Relocatable Loader

An absolute loader is the easiest or simplest type of loading scheme. In this method, the file is loaded at a particular 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.