In system software (linkers and loaders), which operations are performed by the loader during program load and start-up?

Introduction / Context:
In operating systems and system programming, a loader is responsible for preparing a compiled program for execution. It takes the output of the linker (often relocatable or executable object files) and ensures the program occupies appropriate memory with all addresses adjusted correctly so that the CPU can begin execution without faults.

Given Data / Assumptions:

• The prompt lists distinct responsibilities a loader may perform.
• We assume a conventional environment where relocation and symbol resolution may still be required at load time (static or dynamic scenarios).
• The end goal is a runnable image in memory with a proper entry point.

Concept / Approach:

A classical loader will: (1) allocate memory for the program's segments, (2) resolve external symbols not fixed at link time (or finalize relocations), and (3) copy or map program text/data into RAM, then transfer control to the entry point. These tasks correspond to space allocation, relocation/adjustment of address-dependent locations, and physical placement (loading) of code and data.

Step-by-Step Solution:

Verification / Alternative check:

Standard OS texts define loader duties exactly as memory allocation, relocation, binding, and loading, often followed by setting up the initial process state and jumping to the program's entry point.

Why Other Options Are Wrong:

• Options a–c are correct individually but incomplete alone.
• None of the above is false because each listed function is indeed a loader activity.

Common Pitfalls:

• Confusing linker vs. loader roles; linkers produce combined objects, loaders finalize and place in memory.
• Assuming demand-paged systems eliminate loaders; even then, a loader (or the kernel's exec) performs these steps via mapping.

Final Answer:

All of the above.