Question

The first file the computer look for at the start up is :​

Answer 1

The BIOS chip tells it to look in a fixed place, usually on the lowest-numbered hard disk (the boot disk) for a special program called a boot loader (under Linux the boot loader is called Grub or LILO). The boot loader is pulled into memory and started. The boot loader's job is to start the real operating system.

Answer 2

This is the hardware portion of the boot process and is the same for any operating system. When power is first applied to the computer it runs the POST (Power On Self Test) which is part of the BIOS (Basic I/O System). When IBM designed the first PC back in 1981, BIOS was designed to initialize the hardware components.