Difference
between Linker and Loader
·
The utility programmes Linker and Loader are essential to a program's
execution.
·
A program's
source code goes through the compiler, assembler, linker, and loader in that
order before being executed.
·
On the one
hand, the linker is responsible for combining the object codes produced by the
assembler to create the executable module.
· However,
the loader instals this executable module into the
system's main memory for use.
|
LINKER |
LOADER |
|
Basic: It creates a source program's executable
module. |
Basic: The executable module is loaded into the
system's main memory. |
|
Input: It accepts the object code produced by an
assembler as input. |
Input: It uses a linker-generated executable
module. |
|
Function: To create an executable module, it
integrates all of a source code's object modules. |
Function: It assigns the addresses to a main memory
executable module so that it can run. |
|
Type/Approach: dynamic linker, linkage editor |
Type/Approach: three types of loading: absolute,
relocatable, and dynamic run-time. |
Definition
of Linker
The linker receives the object code of a source programme from the assembler. The executable code for the programme is created using this object code by the linker,
which then gives it to the loader.
Programs written in high-level languages often include header
files and libraries. Some library functions whose definitions are kept in the
built-in libraries may be found in the source code of the programme.
These functions are linked to the built-in libraries by the linker. It notifies
the compiler if the built-in libraries cannot be found, and the compiler then
generates the error.
Linkers
come in two varieties.
•
Linkage Editor: This linker creates the executable module that can be
relocated.
• The dynamic linker postpones or
delays linking some external modules until the load module or executable module
is produced. Linking takes place at this point during runtime or load time.
The
meaning of loader
Since the programme that has to be run right now must be stored in the computer's
main memory. The executable file or module of a programme,
created by the linker, must be loaded to the main memory for execution by the
loader, a programme in an operating system. It allots
RAM in main memory for the executable module.
Different loading
strategies:
Absolute and repositionable loading
Run-time dynamic loading