During the bootstrap process of a computer system, what major steps occur from power on until the operating system takes control?

Introduction / Context:
The bootstrap process is the sequence of steps that occur when a computer is powered on or reset, before normal operation begins. The system must initialize hardware, determine where the operating system image resides, and load it into memory. Because the operating system itself is not yet running, a small program stored in firmware and boot sectors performs this early work. Understanding bootstrap helps explain why systems behave as they do when starting and what happens if the boot process is corrupted.

Given Data / Assumptions:

• The machine is initially in a simple state after power on or reset.
• Firmware is stored in nonvolatile memory such as ROM or flash.
• The operating system kernel and boot loader reside on bootable storage devices.

Concept / Approach:
When power is applied, control begins in firmware code such as BIOS on legacy systems or UEFI on modern systems. The firmware performs a power on self test to verify basic hardware, sets up low level interfaces, and then searches for a bootable device according to configuration. It reads a small boot loader program from a fixed location on that device, such as the master boot record or an EFI system partition, and loads it into memory. The firmware then transfers execution control to the boot loader. The boot loader is responsible for locating the operating system kernel, loading it into memory, and then passing control to the kernel, which continues initialization and eventually starts user processes.

Step-by-Step Solution:
Step 1: Start at power on. Recognize that firmware stored in nonvolatile memory runs first.Step 2: The firmware performs hardware initialization tasks and a power on self test, checking devices such as memory and basic controllers.Step 3: Firmware then scans for bootable devices such as hard drives, SSDs, optical drives, or network boot sources.Step 4: After a bootable device is found, the firmware reads a small boot loader program from a predefined location into memory.Step 5: Control is transferred to the boot loader, which loads the operating system kernel into memory and then jumps to the kernel entry point.

Verification / Alternative check:
Observing system startup messages provides evidence for these steps. BIOS based systems often display memory counts and device detection messages. UEFI systems may show logos and quick prompts for entering setup. Errors such as missing operating system or no bootable media indicate that firmware could not find a valid boot loader. Boot managers like GRUB clearly show that a boot loader program is running before the operating system itself. All these observations align with the described bootstrap sequence.

Why Other Options Are Wrong:
Option B: Suggests that the kernel loads itself directly from main memory at power on, which is impossible since memory content is not valid and firmware must initialize hardware first.Option C: Claims that only application programs start directly from disk and no operating system code runs, which contradicts the existence of the kernel and boot loader.Option D: Describes a system that randomly downloads an operating system image at each startup, which is not how standard bootstrap processes work.

Common Pitfalls:
A common misunderstanding is to think that the operating system is always resident in memory. In reality, it must be loaded from storage at boot time. Another pitfall is to overlook the role of firmware, assuming that the boot loader is somehow started without prior code. Knowing the sequence firmware boot loader kernel clarifies responsibilities and helps diagnose boot related problems.

Final Answer:
The correct answer is Firmware such as BIOS or UEFI performs hardware initialization and a power on self test, locates a bootable device, loads a small boot loader into memory, and then transfers control to load and start the operating system kernel.