How does computer work?

Hello everyone, today I would like to tell you all about how the computer works with all its different parts and systems.

Computers are part of our life and many different sectors use it for their business.  Computers help us in many ways, but they don’t do everything for us by themselves, still human resources required to create ideas, write the programs and analyze data.  However,  if you know how to use it and understand it`s outputs,  computer gives extensive opportunities to many different things.

Computer system definitions and functions 

Let’s start with basic description; a computer system is a machine allowing different types of operations, by operating input, storage, data processing, and output. These are the four operations for computer functions.

Figure 1. High level computer system functions

Computer system components 

Computer system has two main components, which are hardware and software. Hardware is the physical aspect of the computer, telecommunication systems or any other devices. An example would be a computer shell that holds everything inside or even a mouse, keyboard, monitors, printers and scanners, which are called peripheral devices (definition is ; auxiliary device that connects to a computer system to add functionality such as Input/Output).  After hardware, the software comes into play. This refers to the programs or set of instructions (codes) and applications used to manage and control various functions of a computer. It is generally split into two groups; system software and application software.  Systems software controls the components and devices connected to the computer system. Some of the examples; Microsoft Windows, Apple Mac OS etc. These software are also known operating systems which provide interface between application software and the computer hardware.  Application software allows users to operate various functions with instructions. The instructions will be provided with different programming languages, such as; Java, HTML, Python, C++, etc. examples for the application software are; excel, power point, etc.

Figure 2. High level view of integration from users to software, operating system and hardware

The network and internet services are also part of the software components and it allows a group of computers to be linked together to exchange data; the links normally go through firewalls for protection. Some very good examples for software network applications would be Google, Gmail, Amazon and iTunes. 

Computer system architecture 

How the hardware and software interact between each other? Next is the CPU (Central Processing Unit), this is a main component of the computer where most of the calculation takes place. Many people call it “the brain of the computer”. CPU interrupts and executes the program instructions. One of the other component is the main memory, and it works with the CPU together. Main memory holds the information (storage) and when any information is needed, it will be extracted from the main memory. Basically, based on the comments that are given, the CPU will process the request, look for info from the main memory, process it and take it out. For example,  if you want to open a PowerPoint slide,  the CPU will go to the main memory, look for the PowerPoint folder and bring the slide`s file and put it to your computer screen. Always remember R.P.P; the three main functions of CPU are to receive input, process data and produce output. 

The computers only understand the machine codes and they are in binary number format which are represented numbers with 0s and 1s. The binary code is a simple program of software and controls all the computer hardware. So we give comments by using different computer programs, next  it is converted to hundreds of binary machine codes that the CPU can understand for different functions.

Let’s look at the CPU and memory in more detail. CPU is divided into three: the ALU (arithmetic logic unit), CU (control unit) and register unit. The ALU is a digital circuit that performs arithmetic (multiplication, subtraction and multiplication) and logical (true or false) operations within the computer and is also referred to as the core. Fun fact, the more ALUs you have in a computer the faster it will run. On the other hand the CPU controls and directs the operations of the CPU around the CPU, from main memory to CPU and CPU to the main memory. If there is a second memory,  it also controls and directs the information between main memory and second memory too. Register unit (Registers) is a temporary small storage in the CPU that allows the CPU to access the information much quickly and increase the speed. 

The computer main memory is the internal working memory of a computer and it includes RAM, ROM, and the cache. The RAM (Random Access Memory); it is volatile, available to applicants and programs. It is as well as temporary storage since it is volatile. The ROM (Read Only Memory); it is non-volatile and stores the BIOS (Basic Input Output System). The cache memory is a type of small, high-speed memory inside the CPU used to hold frequently used data so that the CPU needs to access the much slower RAM less frequently. The need for persistent storage causes after the CPU is done processing the data it needs to store the data is stored in RAM the content is lost, when power is lost. To keep it safe it needs to be stored on persistent storage. The secondary storages are HDD (Hard Diskette Drive), SSD (Solid State Drive), Removable Media and Cloud Storage. 

Figure 3. High level of computer system architecture