What Are Digital Computers?

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Digital Computers


A digital computer can be defined as a device that can process information at a very high speed. A digital computer needs input data that it can process and then it returns the output data. A few examples of digital computers include Laptops, Mobile phones, Tablet PCs, etc.

The digital computers which we have now are capable of performing numerous types of tasks within a very short period. They are reliable and can work for continuous periods without exhaustion.

A digital computer can take the input that is understandable to the user. The input is then converted into machine language and then again into a simple language that the user can understand.  The input and output of the digital computers are in binary code which is 0 and 1. Digital computers are capable of understanding machine language only.

The First Digital Computer:

The first electronic digital computer was invented by John Vincent Atanasoff. He invented it in the 1940s. Clifford E.Berry one of his students was also involved in this invention. The first digital electronic computer was named ABC(Atanasoff-Berry Computer).

It weighed around 700 pounds and was capable of solving up to 29 simultaneous linear equations. It had no CPU, but it used Vacuum tubes for digital computation. ABC had a computation speed of 30 actions per second. The design concepts used in the ABC are still sound and used in computing devices even today.

From weighing a total of 700 pounds to be able to fit in your pockets, there is no denying the fact that technology has come along a long way.

Evolution of Digital Computers:

The evolution of digital computers took place in two eras.

  • Mechanical Era
  • The Electronic Era

Mechanical Era:

The mechanical era is the era in which we first saw the connections between our current technology and its ancestors. This age can be defined as the period between 1450 and 1840.

After many attempts, Charles Babbage built a mechanical computer in 1823. This mechanical computer was capable of performing mathematical calculations.

Later on, he improvised and built a more powerful mechanical computer that was programmable and also had a memory unit. This marked the start of the mechanical Era which later led to the foundation of IBM.

The Electronic Era:

 The electronic era is what we currently live in. The electronic era started in 1940 and yet every day some new inventions do not fail to surprise us.

The first digital computer was ENIAC which could be reprogrammed and was capable of solving many computing problems. ENIAC was designed to be used by the U.S. Army. This machine was big in size and as claimed by resources, it used to occupy a space of 680 square feet and weighed an astonishing 30 tons. This digital computer primarily used Vacuum tubes for its calculations.

Digital computing made progress in four generations. They are:

  • The first generation digital computers used punch cards and vacuum tubes like the ENIAC. It used Rotating magnetic drums for internal storage.
  • The second-generation digital computers used transistors instead of vacuum tubes. This generation of computers used magnetic tapes and magnetic cores. High-level computer languages like COBOL and FORTRAN were introduced in this generation.
  • The third generation digital computers made use of integrated circuits. They also used magnetic tape and he magnetic core used in second generation was now replaced by metal oxide semiconductors. Advanced Programming language BASIC and an actual operating system was introduced in this generation.
  • The fourth and the latest generation introduced Central Processing Units (CPUs) that contained control circuits, memory and logic on a single chip. The GUI was also developed in this generation.

Types of Digital computers:

There are two categories of digital computers-

  • General Purpose
  • Special Purpose

General-purpose computers can be defined as the computers which can given the required applications and time should be able to perform the most common computing tasks. Examples of general-purpose computers include desktops, notebooks, smartphones, and tablets.

Special Purpose computers are built to perform specific tasks, such as washing machines or fridges.

Computer Architecture:

Computer architecture is concerned with the behavior and structure of the computer as seen by the user. It includes the formats of information, techniques for addressing memory, and the instruction set.

It represents how data transfer and processing takes place. Computer architecture can also be defined as the organization of components making up the computer system. It governs the design of a family of computers

  • The basic architecture has a CPU with the main memory along with the input-output system.
  • The second computer configuration is the central input/output controller.
  • The third computer architecture uses main memory for all its flow of data.
  • The fourth architecture uses a common data and control bus to interconnect all the devices.

The different components involved in computer system architecture are the Input unit, output unit, storage unit, Arithmetic logic unit, Control unit.

  • Input unit: The computer needs data from the external environment to perform its operations. The input unit provides input to the computer system from the outside with the help of various input devices.
  • Output unit: Once the computer is done processing the data, the processed data is sent to the output unit where the user can interact with it.
  • Storage unit: Storage unit is divided into primary storage and secondary storage and it consists of various computer components.
  • Arithmetic Logic Unit: This unit deals with all the calculations. It can perform all basic arithmetic calculations which include addition, subtraction, division, etc.
  • Control unit: This unit can be considered as the central nervous system of the CPU. This unit controls all other units. This unit decides how all other units should behave.

Some useful types of Digital computer architectures are :

  • Von Nuemann Architecture:

This architecture was proposed by John Von Neumann in 1945. This architecture constitutes a Control Unit, Arithmetic and Logic Unit, Memory unit, Registers, and Input/outputs.

The computer architecture proposed by Von Neumann is based on the stored-program computer concept, where instruction data and program data are stored in the same memory.

The Von Neumann architecture is still being used in many computer architectures.

  • Harvard Architecture:

This computer architecture contains separate storage and separate buses for instruction and data.

The components of Harvard architecture include Buses, Operational Registers, Program Counter, Arithmetic and Logic Unit, Control Unit, Input/Output System.

The Harvard architecture can access instructions and read/write data at the same time unlike the Von Neumann Architecture.

  • Instruction Set Architecture:

This Computer Architecture is more concerned with the analysis and design of instruction set architecture.

This architecture defines the types of instructions, the maximum length of instructions, and the instruction format of each type of instruction.

  • Microarchitecture:

A microarchitecture is a digital logic that allows an instruction set to be executed.

A microarchitecture combines with an instruction set architecture makes up a complete computer system architecture.

Working of Digital Computers:

A typical Digital Computer consists of four units:

The basic working model of any Digital Computer:

  • The input devices are used to provide input to the computer. The input devices can include the keyboard, mouse, etc.
  • The information received via the input devices is stored in the main memory or auxiliary storage device. (Auxiliary storage is nothing but external storage devices or secondary storage)
  • The control unit selects and calls instructions from the memory in proper sequence and passes the proper commands to the appropriate units.
  • It synchronizes the speed of input and output devices to ensure the proper movement of data through the entire system.
  • The Arithmetic and Logic unit performs the required calculations at very high speeds
  • The processed data is then sent to the output device where the user can interact with the data.

The CPU constitutes the main memory, Control Unit, and ALU, while the input-output devices and auxiliary storage unit constitute peripheral equipment. 

Advantages of digital computers:

 We live in a digital world where most of the data is transmitted or stored digitally. Digital computers have made our life much easier. Some of the advantages of digital computers are :

  • Digital computers have helped people in all fields to attain advances that would not have been possible otherwise.
  • Huge amounts of data can be easily stored and it does require large spaces.
  • Unlike human beings, digital computers can never be tired of repetitive tasks, which makes them more efficient than humans in various fields.
  • Huge amounts of scientific calculations can be done on these digital computers.

The advantages of digital computers seem to have no end. Technology has proved to be a boon for everyone. We can be more connected with people living far away from us. We can share data easily with literally anyone across the globe.

But this has also proved to be a curse. Since all the data is readily available, it can be misused as well. With data, exploration comes data exploitation. We are so lost in seeking benefits from the digital age that we can hardly focus on the possible dangers it brings to us as well.

According to you, What measures can be taken to make the digital world a safer place for everyone?

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