In this blog post, we’ll explore the origins of the computer and its evolution from early computing devices to electronic computers and personal computers. We’ll also examine how changes in hardware and software have shaped today’s computers and look at the direction in which future computer technologies—such as quantum computing and DNA computing—are heading.

How did the concept of the computer emerge from simple calculating tools?

Computers have become indispensable tools for many people in modern society. Computer technology is widely used in smartphones, automobiles, financial systems, communication networks, medical devices, and industrial equipment. However, in the past, many people were unfamiliar with the very concept of a computer, and even those who were aware of them could hardly have anticipated that they would be used in nearly every aspect of society as they are today. Considering the limited storage capacity and computational power of the past, it would have been difficult to imagine a future where vast amounts of information are stored as digital data and shared in real time across the globe via the Internet. So, for what purposes were computers created in the past, and how were they used? By examining the history of computers and comparing them to modern ones, we can also contemplate what form and functions future computers might take.
In ancient times, various tools were used to aid in calculations, the most representative of which was the abacus. Calculation tools similar to the abacus were developed in several ancient civilizations, and the abacus was widely used for a long time, particularly in East Asia, including China. The abacus is a calculating tool designed to represent numbers through the position of its beads and to perform the four basic arithmetic operations more conveniently. However, since a person had to manually move the beads to perform calculations, it differed significantly from the automated computers we think of today. Later, in Europe during the 17th century, Blaise Pascal invented the Pascaline, a mechanical calculator. The Pascaline could perform operations such as addition and subtraction using gears and mechanical devices, and it is significant in that it mechanically assisted human calculation tasks. Calculating devices from this period were essentially machines that required human force or direct manipulation to operate.
In the 19th century, Charles Babbage designed the Analytical Engine, a concept very similar to the structure of today’s computers. The Analytical Engine included concepts corresponding to a “Store” (a storage device for numbers and intermediate calculation results), a “Mill” (an arithmetic unit that performs actual calculations), a device for inputting commands and data, and a device for outputting calculation results. Since the design even included the concept of using programs to control the calculation process, it can be regarded as a pioneering proposal that laid out much of the basic structure of modern general-purpose computers. However, due to limitations in precision engineering technology and cost at the time, the Analytical Engine envisioned by Babbage was never fully constructed during his lifetime.

How did the war affect the development of electronic computers?

Computer technology advanced rapidly around the time of World War II, and several countries—including the United States, the United Kingdom, and Germany—developed computing devices and electronic information processing technologies. Unlike early mechanical computing devices, the full-scale utilization of electricity and electronic circuits made much faster computations possible. Electrical signals could change states very quickly and be expressed as logical states, making them well-suited for implementing digital computers. Many of the computing devices developed at that time were closely linked to military purposes, such as ballistic calculations for artillery shells and missiles, scientific computations, and cryptanalysis. In particular, some computer systems related to cryptanalysis were classified as military secrets, so their existence and technical details remained undisclosed for a considerable period even after the war ended.
Which of the early electronic computers should be called the “first computer” depends on how one defines a computer. The Atanasoff–Berry Computer (ABC) was an electronic digital computing device developed by John Vincent Atanasoff and Clifford Berry between 1939 and 1942; it was a special-purpose computer designed to solve systems of linear equations. While it holds a very important place in the history of computing for applying key concepts of electronic digital computation to an actual device, it was not a general-purpose computer in the modern sense—one capable of freely executing a variety of programs. Therefore, rather than simply declaring either the Atanasoff–Berry Computer or the ENIAC to be “the first computer,” it is more accurate to distinguish which is considered the first based on specific criteria.
The ENIAC, which appeared later, was a significant device that symbolized the development of large-scale electronic general-purpose digital computers. Development of the ENIAC began in 1943 during World War II, and it was unveiled to the public in 1946. Unlike most digital computers today, which use the binary system internally, ENIAC’s main computing unit operated on a decimal basis. Furthermore, in the early days, programs had to be modified by reconnecting cables and adjusting switches, which was vastly different from today’s method of loading a program file and executing it immediately. The ENIAC used approximately 18,000 vacuum tubes, weighed about 30 metric tons, and required a large amount of space and a massive amount of power. For these reasons, early large-scale electronic computers were not devices for individual use but were primarily operated by large organizations such as military agencies, government agencies, and universities.

How did personal computers become possible?

As computer technology advanced, the era of personal computers—where individuals could own and use computers—began. Early computers were very large and consumed a great deal of power because they required numerous vacuum tubes and electronic components. However, with the advent of transistors and advancements in integrated circuit and semiconductor manufacturing technologies, it became possible to integrate numerous electronic components into a very small space. Advances in integration technology not only significantly reduced the size of computers but also played a crucial role in improving performance and reliability while lowering power consumption and manufacturing costs. Furthermore, as microprocessor technology advanced, it became possible to implement the main functions of a central processing unit (CPU) on a single small chip, laying the foundation for the rapid proliferation of personal computers. As computers became widespread not only in businesses and research institutions but also among individuals, the scope of software development and application expanded significantly, and computer technology advanced even more rapidly.
Throughout the history of computer development, terms such as “8-bit,” “16-bit,” “32-bit,” and “64-bit” have been frequently used. Here, a “bit” is the basic unit of digital information that can represent two values: 0 or 1. Therefore, it is not accurate to understand the “number of bits” as the length of the minimum amount of information a computer can process. Depending on the context, terms like 8-bit, 32-bit, and 64-bit refer to characteristics of computer architecture, such as processor register size, data processing units, and address space. Currently, 64-bit processors and operating systems are commonly used in personal computers and servers. Improvements in the performance of the central processing unit (CPU) played a key role in this development. The CPU is the core component that interprets program instructions, performs arithmetic and logical operations, and controls the computer’s various devices to carry out tasks. Although it is often likened to the human brain, in actual computer systems, not only the CPU but also memory, storage devices, graphics processing units, and various input/output devices work together.
Looking back at this progression, it becomes clear that examining the history of computers is necessary to understand what a computer is. This is because the form and function of the machines referred to as “computers” have changed significantly over time. While early computers were primarily machines designed to assist humans with calculations, they later evolved into general-purpose machines capable of processing various types of information according to programs. At the heart of these changes lie advancements in both hardware and software. While it is difficult to say that these two fields have necessarily developed alternately in a fixed sequence, it can be argued that there has been a repeated cycle of interaction: advances in hardware enable new software, and the demands of new software, in turn, drive further hardware development.

How have hardware and software evolved together?

To understand the evolution of hardware, we must first examine what hardware means. Hardware is a term that collectively refers to the physical devices that make up a computer. All computer components that have a tangible physical form—such as the CPU, memory, storage devices, motherboard, graphics processing unit, keyboard, and monitor—are considered hardware. Viewed from this perspective, the history of computers shows that while abacuses and mechanical calculators centered on machines operated directly by humans, computers gradually evolved into smaller, faster, and more efficient devices as electromechanical devices, vacuum tubes, transistors, integrated circuits, and microprocessors developed in succession. Recently, hardware architecture has been evolving not only by simply reducing the size of components but also by integrating various computational units—including multiple CPU cores and GPUs—into a single system to efficiently perform calculations tailored to specific purposes.
Software can be defined as a collection of programs and related information that enables a computer to perform specific tasks. As computer languages and programming techniques have advanced, people have been able to develop increasingly complex and efficient programs. As hardware performance improves, new software emerges to take advantage of that performance; conversely, when software demands more computing power, memory, and storage space, the need for new hardware technologies increases. Therefore, it is difficult to explain the advancement of computers based on the development of just one aspect—hardware or software—alone. The development of various software technologies—such as operating systems, programming languages, databases, networks, and artificial intelligence—has occurred in a mutually reinforcing relationship with new hardware technologies.
In this way, the development of hardware and software has complemented each other, expanding the performance and scope of computer applications. While software technology has advanced to a very high level in today’s computers, CPUs, GPUs, memory, storage devices, and semiconductor manufacturing technologies are also continuing to evolve. Therefore, it is difficult to view future computers as simply the next stage of either hardware or software alone. Rather, as hardware that utilizes new computational principles and software that efficiently controls it develop together, it is highly likely that computers of a form different from today’s will emerge.

Could quantum computers and DNA computing become the computers of the future?

Future computer technologies that utilize principles different from those of conventional computers—such as quantum computers, molecular and chemical computing, and DNA computing—are currently being researched. These technologies employ an approach that differs from simply making the silicon semiconductor-based general-purpose computers currently in use smaller and faster. However, it is difficult to conclude that these technologies will completely replace conventional computers. Since each has the potential to demonstrate advantages in specific types of computations or environments, it is also highly likely that they will evolve to be used alongside conventional computers.
A quantum computer is a computer that utilizes quantum mechanical phenomena such as superposition, entanglement, and interference in its computations. While conventional digital computers use bits as their basic unit of information, quantum computers use qubits. A classical bit takes on a value of either 0 or 1 when measured, but a qubit can exist in a superposition state—where the quantum states corresponding to 0 and 1 are combined with a certain probability amplitude—until it is measured.
This should not be understood as the existence of a simple “third state” in addition to 0 and 1. When multiple qubits are combined, n qubits can represent a superposition of n² basis states, and quantum algorithms are designed to perform efficient calculations for specific problems by utilizing these characteristics and quantum interference. However, not all computations can be processed faster than with conventional computers, and since a measurement yields a single result, it is not possible to read all possible values at once. In current quantum computing research, key challenges remain in stably controlling qubits, reducing errors, and implementing error-correcting quantum computers of sufficient scale.
DNA computing is a molecular computing technology that utilizes DNA molecules for representing information and performing computations. DNA forms a double helix structure in which two strands are twisted around each other; the basic backbone of each strand consists of the sugar deoxyribose and phosphate groups. There are four types of DNA bases: adenine (A), guanine (G), cytosine (C), and thymine (T); adenine pairs with thymine, and guanine pairs with cytosine. By utilizing these complementary base pairings and various chemical reactions between DNA molecules, it is possible to represent information at the molecular level and perform logical operations. DNA computing holds significant research value because it can store large amounts of information in a very small space and carry out a large number of molecular reactions in parallel. However, it would be incorrect to assume that outcomes such as human lifespan or the likelihood of developing cancer are simply recorded as a single value in DNA. DNA contains the genetic information of living organisms, and while specific genetic mutations can influence disease risk, human lifespan and cancer incidence are influenced not only by genetic factors but also by a variety of other factors, including the environment and lifestyle habits. Currently, DNA is being researched not only for molecular computing but also in fields such as ultra-high-density data storage, biosignal detection, and diagnostics.

How will advances in software change the computers of the future?

Having explored the new possibilities of hardware, we can now consider how advances in software will influence the computers of the future. As software advances, we can utilize the performance of existing hardware more efficiently. In the past, systems using two or more CPUs were considered a novel technology in themselves, but today, multicore CPUs with multiple cores are commonly used in personal computers and servers, and large-scale servers utilize a variety of computing devices, such as multiple processors and GPUs, in tandem. However, simply connecting multiple computing devices does not automatically increase program execution speed by the same proportion. Programs must be designed to divide tasks into multiple parts for simultaneous processing, and operating systems, compilers, and programming tools must also support efficient collaboration among these computing devices. Therefore, parallel and distributed processing technologies can be considered crucial software technologies that bridge the gap between hardware performance and actual program performance.
Memory, too, cannot be explained simply as a matter of connecting multiple RAM modules to increase capacity. While modern computers can achieve very large capacities using multiple memory modules, an increase in memory capacity does not automatically make every program run faster. Other factors are also crucial, such as how quickly data can be transferred between the CPU and memory, how multiple processors access memory, and where data is stored. Consequently, future software is likely to evolve further in the direction of efficiently utilizing various computing devices—including CPUs and GPUs—along with large-capacity memory, while coordinating tasks across these devices. Ultimately, to convert the computational power provided by hardware into actual performance, software that understands and leverages this power is essential.

How, then, can we ultimately define a computer?

So far, we have examined the past, present, and future possibilities of computers. The reason we must look at history when considering the definition of a computer is that computers have been constantly evolving with the times. Starting with abacuses and mechanical calculators, they evolved into electronic computers and personal computers, and today, complex computing systems that combine different types of computational devices are in use. In the future, technologies that utilize computational principles entirely different from those of today—such as quantum computers or DNA computing—may also emerge. For this reason, it is difficult to fully define a computer based solely on the characteristics of any single era. Nevertheless, based on their history to date, we can define a computer as a machine that combines hardware and software to store and process input data and commands, and output the results, thereby efficiently performing the various information processing and computational tasks required by humans. Understanding the past and present of computers from this perspective allows us to consider the future direction of their development and the role that new computer technologies should play in human society.