Computer System

What is a computer system?

   We can define a computer system as a system composed of hardware and software. This definition tells the parts composing the computer system. From a logical perspective we can define a computer system as a system which accepts input from the user(person, sensor, other computer system), processes this input through algorithms and gives output to the user. The output can take various forms as information printed on hard copy, information on a screen or even actions taken through actuators.

   The hardware of the computer system are the electric and electronic components of this system. So we can say that hardware is everything touchable or physical of a computer system. The software is the set of instructions that make the hardware of the computer system usable. In contrast with hardware, the software is the logical component of the computer system. Usually software components fall into two categories: the system software(operating system) and application software.

Generally the hardware of the computer system can be summarized with this picture:

   The most important part of the computer system("the brain") is the CPU(Central Processing Unit). This component is responsible of every calculation made in this system. The memory is the area where software and data used by the system are kept during execution. Memory stores instructions which are taken from the CPU and executed in order to give output. Main memory is volatile so it loses information when it is disconnected from energy source. In our daily language we call main memory RAM(Random Access Memory).

   Storage devices are components which store information(software and data) even when energy source is disconnected. This devices can store information for long time and this information can be reused when needed. Example of storage devices are HDD(Hard Disk Drive, Flash Drives, Optical CDs).

Communication devices are those devices used when computer systems are connected with each other in order to communicate or share information(the Internet). As examples we can mention hubs, bridges, switches and routers. 

   Input devices, as the name implies, are a mean of inserting information to a computer system in a form that a "user" can understand. Contrary output devices output information in a form that a "user" can understand.

   Certainly this hardware components need to communicate in order to fulfill the purpose of a computer system. The bus illustrates the mean of communication between the hardware components mentioned above. They come in different types and each type is used for a different purpose. Whenever a hardware component needs to communicate with any other hardware of the computer system it needs to use the bus in order to transmit information.