In a typical personal computer, which program is responsible for loading the operating system into main memory so that it can begin execution?

Introduction / Context:
When you power on a computer, several layers of software run before the full operating system kernel starts executing. Understanding which program actually loads the operating system image into main memory is a fundamental concept in operating systems and computer organisation. This question asks you to identify that program.

Given Data / Assumptions:

• The computer follows a standard boot sequence.
• Firmware runs first, then control passes to a program on a storage device.
• That program loads the operating system kernel into RAM.
• No numeric calculation is needed.

Concept / Approach:
After power on, the firmware performs basic hardware initialisation and runs a small bootstrap program, often called the boot loader. The bootstrap program is responsible for locating the operating system kernel image on disk or another device, loading it into main memory and transferring control to it. The BIOS or other firmware may include or invoke the bootstrap code, but the key term used in operating system discussions for the component that loads the kernel is bootstrap program or boot loader.

Step-by-Step Solution:
Step 1: Recall the general boot sequence: firmware initialises hardware, then a boot loader loads the operating system. Step 2: Identify that the operating system kernel is stored on a secondary storage device and must be copied into RAM before execution. Step 3: Recognise that the bootstrap program or boot loader performs this copy and then jumps to the kernel entry point. Step 4: Compare the options and choose the one that explicitly mentions bootstrap program or boot loader. Step 5: Discard options that refer only to configuration utilities or device drivers that run later in the boot process.

Verification / Alternative check:
Operating system textbooks typically introduce the concept of a bootstrap program in the first chapter, explaining that it is stored in read only memory or loaded by firmware and is responsible for starting the operating system. References to common boot loaders such as GRUB illustrate this role in practice. This matches the correct option and differentiates bootstrap program from other system components.

Why Other Options Are Wrong:
Option B refers to the BIOS configuration utility, which allows users to set firmware parameters but does not itself perform the main kernel loading function. Option C, a device driver for the hard disk, is part of the operating system and is not available before the operating system has been loaded. Option D, a supervisor program running as a user application, would only exist after the operating system is already running, so it cannot be the component that initially loads the operating system into memory.

Common Pitfalls:
Students sometimes confuse firmware, such as BIOS or UEFI, with the bootstrap loader, or assume that the operating system somehow loads itself without a dedicated loader. Another mistake is to think that device drivers initialise hardware and also manage the entire boot process; in reality, boot loaders are specialised programs dedicated to loading the kernel image.

Final Answer:
The program responsible for loading the operating system into RAM is the bootstrap program or boot loader.