Block Diagram of a computer/What is Hardware & Software of Computer

Block Diagram of a computer.

Block Diagram of a computer

Figure shows the block diagram of a typical computer.The major parts are the central processing unit or CPU,primary and secondary memory and input / output devices.

Central Processing Unit

The CPU or Microprocessor is the heart of the computer,which control the basic operations inside computer.It fetches the binary-coded instructions from the memory,decodes the instructions into a series of simple actions, and carries out these actions. The CPU includes an arithmetic logic unit (ALU), which can perform arithmetic and logical operations on binary words when instructed to do so.CPU contains registers for temporary storage.CPU also contains an address counter which is used to hold the addresses of the next instructions.General purpose resister (GPU) which are used for temporary storage of data.

Memory

The purpose of memory is to store the binary instructions to be executed by the computer. It also store binary data which the computer process. The size of the memory determines the amount of memory we can use for programs and data. There are two types of memory -RAM and ROM.

Random Access Memory(RAM)

This is a volatile type of memory, meaning that the content of memory is lost when power is not present.This is made of Dynamic RAM technology and is installed as modules to the memory slots present in the motherboard.

Read Only Memory (ROM) 

This is a non volatile type of memory.That means the content of the memory is not lost when if power is not present.This is generally used of firmware IC. Firmware is the term given to Programs stored in the ROMs or in other devices, which keeps their stored information when the power is tuned off.

Secondary Memory 

Secondary memory is used to represent other data storage devices of the computer system like Hard disk drive,floppy drive, CD drive etc.

Difference between main memory and secondary memory.

• The main memory is often volatile whereas the secondary memory is permanent memory.
• The capacity of main memory is often less than the secondary memory.
• The speed of main memory is very high compared to secondary memory.

Main memory is made of semiconductor technology whereas the secondary storage device work based on magnetic (eg in HDD,FDD or magnetic tape drives) or optical principal (like CD ROM or DVD Drives)

When power on the computer Operating system stored in hard disk drive is copied to main memory.This process is called booting.