What is the main purpose of BIOS?

The main purpose of the BIOS, or Basic Input/Output System, is to manage hardware initialization during the boot process when a computer is powered on. It performs a POST (Power-On Self-Test) to check the hardware components, ensuring they are working correctly before loading the operating system from a disk. This initialization includes detecting and interfacing with core hardware components such as the CPU, RAM, and storage devices.

Once this hardware setup is complete, the BIOS helps in transferring control to the operating system by loading it into the system memory. The BIOS also provides runtime services for operating systems and programs, such as basic input and output operations.

In contrast, the other options refer to functions that are not roles of the BIOS. Network access is typically managed by networking hardware and software components after the operating system is loaded. Compiling code at runtime is an activity associated with programming languages and their runtime environments rather than BIOS. Executing complex applications falls under the domain of the operating system and higher-level software, which take over once the BIOS has done its job in initializing the hardware and loading the system.