Computer: How it starts

Here I am going to discuss about how computer starts for beginners. Computer is an electronic device to perform computations based on the input by the users. This does seem to describe the present day computer. well, I will go step by step describing it. First we start the computer by switching it on the power button, now what happens, the ROM comes into picture(what is ROM?).Read Only Memory.(why ROM?) the processor which is present in the mother board can only compute the data in the electronic form. Our operating system which is present in the hard disk can't be accessed by the processor directly, so it needs some initiator which should not be modified. ROM is the first program to be executed to start the booting(the progress bar shown when windows is starting) which means now the booting is initiated which will load the necessary components in another volatile electronic memory called RAM(Random access memory). Now the processor can access the RAM now the operating system is ready for user to communicate and take requests from user and give reply.