Page 128 - DCAP507_SYSTEM_SOFTWARE

System Software

Notes Compile and go Loader: In "Compile and go" loader , the instruction is read line by line, its
machine code is attained and it is directly placed in the major memory at some recognized
address.
Direct Linking Loader: The direct linking loader is the main common type of loader which is a
relocatable loader.

General Loader: In General Loader Scheme loader scheme, the source program is transformed to
object program by some translator (assembler).
Loader: Loader is defined as a utility program which considers object code as input organizes it
for implementation and loads the executable code into the memory.
Relocation: Relocation is the procedure of modernizing the addresses used in the address sensitive
instructions of a program.
Relative Address: The relative address is only after the addition of relocation constant to the
object code address.

Subroutine Linkage: The general process of establishing the relations among the subroutines
can be theoretically known as a_ subroutine linkage.

8.5 Review Questions

1. What is a loader? Illustrate the functions of loader.
2. Describe the concept of "Compile and go" loader scheme with example.
3. Enlighten the advantages and disadvantages of "Compile and go" loader scheme.
4. Explicate the loader scheme of transforming the source program to object program by
some translator (assembler).
5. What is absolute loader? Illustrate its advantages and disadvantages.
6. Write an algorithm for absolute Loader.
7. Explain the concept of subroutine linkage with example.

8. What are relocating loaders? Illustrate the concept.
9. Make distinction between binders and linkers.
10. The overlay structure comprises multiple root/nodes and edges. Comment.

Answers: Self Assessment

1. Loader 2. "Compile and go"

3. General Loader 4. Absolute loader
5. EXT 6. a_ subroutine
7. Relocation 8. absolute
9. relative 10. binder

11. linkage editor 12. object module
13. bootstrap loader 14. overlay
15. dynamic

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