Fundamentals of computer : Introduction

What if it was said to you that somehow Hitler is the reason why you can browse anything on the web today and get an answer?

It may sound dumb and jarring, but here is how it started. British mathematician Alan turning was handed the job to decode Nazi secret messages during World War-2. He would go on to create a machine that, if given a cryptic input with a specific formula, would give an output keeping the formula in mind. That machine during the war was secretly called the Turing machine. Now it’s called the computer.

A compatible device was needed to do fast calculations and keep up with the rising demand for information and storage of it. Computer means to compute; in other words, to calculate. Computers have come a long way from doing mathematics to now calculating our behaviour through algorithms.

The evolution of computers happened from the binary language of the 0’s, and 1’s to high-level languages of today like C, C++, JavaScript etc.

The computer is an electronic device and works on electronic signals. The on and off signals denote 1 and 0, respectively. The binary language, also called machine language, works on two digits, 0 and 1.

Over the years, high-level languages such as C, C++, and Java have evolved using basic English language commands. Commands given in high-level languages need to be converted into binary language with the help of translators.

This evolution is possible because of the close coordination of the components of the computer, i.e., between hardware and software. In simple terms, hardware is one that is tangible(you can feel and touch), like the keyboard, mouse, monitor etc.
Software, on the other hand, is something that is a set of instructions and is intangible. Some examples are MS Word, MS Excel, online calculators, operating systems and other apps you use for shopping online etc.

The data and/or instructions given by the user to the machine are termed Input and the result generated by the machine after processing the data is the Output. For example: when you are filling an application form online, the data you enter such as first name, last name, address, etc. is the input that is entered by the user and once the form is completed, the machine processes it in the backend(background) and displays a message such as, “Form entered successfully.” This is the output.

Let’s look at the characteristics of the amazing performance of a computer:

1. Speed – Computers have the processing to render and work on information and input that is given to them at a very quick pace. It is said that a computer of high quality can perform up to 3 to 4 (million instructions per second) MIPS. Baud is used to measure the speed at which information is sent over a data channel.
2. Versatility – Being able to do all sorts of tasks with ease is called versatility. This is the quality modern computers possess as you can do all sorts of functions depending on your need.
3. Accuracy – A machine can never make a mistake, as it has no room to understand the difference between right and wrong. It works on its input provided or instructions given, so it can only be a wrong input or instruction that may lead to an inaccurate output. Human error is what makes a computer inaccurate.Note that the errors that one may see in output produced by the computer are not because of the machine but because of either wrong entry of data or wrong instructions given to compute. In computer terminology, this phenomenon is often referred to as GIGO (Garbage In Garbage Out)
4. Diligence – Humans can easily get bored of doing the same task again and again. We become emotionally exhausted about it and quit a task in the name of boredom. This is not the case for computers as they can do the same tasks hundreds of times.Another noteworthy feature of computers is their ability to perform the same task repeatedly over and over again without getting bored! For example a task of adding 1000 numbers repeatedly for 1000 times, if given to a computer, it would be able to do the task with the same accuracy every time without complaining that it is being asked to do this job over and over again!!!
5. Memory – Humans are always subconsciously wondering about something. One thought makes us happy, and the other makes us hate a person we know. It is all chaotic and tangled. We can’t even remember sometimes why we are feeling a certain way.One of the notable features of a computer is its memory. However, the computer’s main memory is volatile, i.e., it is lost when we switch off the computer.Therefore, computers are provided with another form of memory that does not fade away when it is switched off. It is called secondary memory and is available in the form of floppy disks, pen drives, portable hard disks.
6. Storage – Humans have limited space for information in their brain, for computers can store very large amounts of data.
7. Intelligence – Computers have the ability to understand what they currently use and work accordingly. In the early days, although computers possessed striking characteristics, they were limited by certain tasks only.
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   Today, technologies like Artificial Intelligence are used to drive a car without a driver (self driving cars), control your home lights, dishwasher, washing machines with a remote somewhere far away, create robots that can deliver food in cafeterias etc.So, a computer is an intelligent device that can store huge amounts of data, remember a ton of things, perform highly intelligent, fast actions/tasks that a human being cannot do.

Now that we know the characteristics of a computer let’s look at the components of a computer.

Different parts of a computer

Just like we have different parts of our body like the head, the arms and legs and other parts, a computer has different parts too. Mainly a computer has:

1.CPU

CPU stands for Central Processing Unit. It is the main component of a computer. It is the part that processes all the input data and converts them to outputs which may be stored somewhere or displayed on the screen.

A CPU is just like our brains. When we want to raise our hands, our brain has to give us the command just like that when we do anything on our computer, it’s the CPU that makes it possible.

A CPU two components in it –

• ALU (Arithmetical and logical unit): This part performs simple arithmetic and logical tasks.
• CU (Control Unit): This part handles all the components of a computer. It reads and interprets instructions from the memory and changes them into a series of signals to activate the other parts of the computer.
• Cache: This is a high-speed memory where information can be stored and restored for a limited time.

2. Monitor

A monitor is the main output device. It is also called the VDU i.e. Visual Display Unit. It is used to display data from the computer. A monitor is used to show the images, videos, words processed by the CPU.

It is like the mobile screen where we see all the images, videos, words etc. A monitor looks like a television but it does not have a television tuner to change channels. There are two types of computer displays:

• CRT Monitor: These are also called Cathode ray tube monitors. They are very heavy and use a lot of desk space. It is the oldest technology used by monitors. They are made with Cathode ray technology. These types of computers are no longer popular now.
• LCD Monitor: It is the most common type of monitor nowadays. They are flat, lightweight and use less space and electricity. They use Liquid Crystal Display technology which is a much better technology than CRT. Having an LCD monitor in the age of CRT was unique and now it is the other way round.

3. Keyboard

We type in our phones using a keyboard right? Well, a keyboard for the computer looks like a giant chocolate bar with keys on top of it just like in our phones that are used to type on the computer. It is one of the main input devices for a computer.

You have letters and numbers arranged in a certain layout on a keyboard. The most famous arrangement is the QWERTY arrangement. There are also keys like backspace, delete, home, end, etc.

4. Hard Disk Drive

The hard disk drive is a storage device that can store a large amount of data for a long time. This is like the memory card of a cell phone. There are two types of hard disk drive:

• Internal Hard disk – This is the main storage device of any computer. It is attached inside the CPU box and is fixed. All the data stored in the c drive of a computer is basically stored in a Hard Disk. It is a magnetic secondary storage device for storing the data and is fixed in the box of a computer.
• External Hard disk – This is a portable device used to store data. It can be carried anywhere and used on any computer to transfer data. Examples: Pen drive / Flash drives- They are small pens like storage devices that can be accessed via the USB (Universal Serial Bus) Port. They are very popular these days because of their small size and easy accessibility.

Speaking of storage, let’s look at the different range of storage measurements and how they are valued. All components coordinate and this is how the operating systems work.

5. RAM

RAM stands for Random Access Memory. It is a type of memory that is located on the motherboard. It is used to store data but temporarily stores data. This data gets erased as soon as the computer is turned off. RAM is of two types: Static and Dynamic RAM.

Static: In layman’s terms, static RAM is like an SD Card of your phone. This helps in speeding up the working of the computer.

Dynamic: This is like the main memory of your computer. More like the internal storage of your phone.

6. Motherboard

A motherboard is the main circuit board inside a computer that connects all the parts of a computer. It has sockets for CPU, RAM and other cards.

It is connected to the hard disks, disk drives by wires and cables. Sounds like our mother? Yes, that is where the name comes from. It’s the main unit of a computer.

7. ROM and BIOS

Read-only memory (ROM) is a type of computer memory that stores data permanently, that is it can hold the data even after the computer is shut down. In ROM, data can be read but is difficult to modify.

BIOS is a chip inside the ROM. Its full form is a Basic Input / Output System. It is used to check and get the hardware ready while booting.

8. Sound And Video Cards

The sound card is what gives the sound to the speaker and the video card is what gives the video to the monitor. Together, they help in making the video, image or sound quality better for the computer.

How does a computer work?

The data from the user is entered into the CPU using the input devices like the mouse, keyboard etc.

Then the CPU processes the information it was given with the help of the different components present inside it. Once the output is ready, it is sent through the output devices like the monitor, speaker etc. back to the user.

How does a computer process?

The computer processes data following few steps:

1. Input – Before the computer can process anything, the input must be entered into the computer using the input devices. All the input is understood by the computer in the binary language (0s and 1s).
2. Process – After a computer has received the input, a program is used to process that information. A program calculates and organises the data into a presentable form.
3. Output – After the data is processed into information, it is displayed as output to the user. The result of the processing carried out by the computer is often directed to the display device such as the monitor or printer. Other forms of devices are not uncommon; for example, the computer may output music or video.We have seen above that the input unit receives data, which is stored in the main memory, from where it gets transferred to the Central Processing Unit and subsequently to the output device. The Central Processing Unit has two modules; the Arithmetic Logic Unit and the Control Unit.It also coordinates between memory and ALU by issuing timely signals. As mentioned above, the storage unit has primary storage and secondary storage.
4. Storage – At the end, the computer can store the output information for later use.

Primary Memory: Data stored in Primary Memory is directly accessible by the CPU. The inputs received in the above steps are stored in the computer memory, called random access memory (RAM). This storage is relatively fast and expensive as compared to secondary storage.

Primary memory is directly connected to the CPU. It is also called the main memory, primary memory, or working memory of the machine.

Primary memory is of two types :

1. RAM ( Random Access Memory): It is a primary volatile memory, i.e. its data gets lost once the power supply is stopped.

RAM is of two types: DRAM (Dynamic Random Access Memory) and SRAM ( Static Random Access Memory.

2. ROM ( Read Only Memory): It is generally used in startup operations of computers. It is a non-volatile primary memory. Further, it may be classified as ROM, PROM (Programmable read-only memory), EPROM ( Erasable Programmable read-only memory), EEPROM ( electrically erasable Programmable read-only memory)

Secondary Storage: The memory which is external to the computer system forms the secondary storage; for example, magnetic tapes, compact disks, pen drives are all examples of secondary storage. These are not directly connected to the CPU.

Cache Memory: it is a very high-speed memory that is used to cope -up with the high speed of the CPU. It is generally placed between CPU and Primary memory and acts as a buffer. It reduces the average access time to data from the main memory and is comparatively expensive.

All the inputs, the intermediate results of computation carried out, and the final result are stored in the memory of the computer. The computer also has another form of memory called secondary memory. The programs and data not currently required are stored in secondary memory. It comes in the forms such as a hard disk, pen drive, and CDROM. When needed, for processing, these can be retrieved and transferred to the main memory of the computer, Processing: The inputs provided by the user are processed by the central processing unit as per the specified instructions. The result of the processing is then either directed to the output devices or to a memory location for storage.

Inside the Computer

There are various types of computers in the market these days, desktop personal computer– popularly known as PC, laptop (also called notebook) – a small computer that can easily be put on your lap, tablet – a light computer the size of a handbook, often used for working on the Internet.

If we look at a personal computer from the outside, it looks like a box (sometimes called CPU) that contains a CPU and hard disks, keyboard, mouse, monitor and speakers. The keyboard, mouse, speakers, printer and other attachments like- a scanner constitute the peripherals. The major functionality of a computer is done in the Processing Unit. The Processing Unit takes input and processes it through the set of instructions ( given in the software) for that input, and finally, it gives the results to the output unit.