In this blog post, we’ll provide a simple introduction to the five key functions a computer performs from receiving input to processing it and producing output.
A computer is a machine that automatically performs everything from simple calculations to complex operations that are difficult for humans to do. For example, computers can perform not only basic calculations like simple addition, subtraction, and multiplication, but also advanced operations such as calculus and complex matrix calculations. They are also used as tools for various fields that apply mathematics. For instance, computers can handle complex calculations for weather forecasting or rocket engineering.
However, today’s computers go far beyond computational functions and are capable of much more diverse applications. You can use a computer to write documents and systematically store vast amounts of data. Not only that, but computers also offer a wide range of entertainment functions. You can play computer games, create or edit videos and music, and enjoy multimedia content. Furthermore, you can search for vast amounts of information online or communicate with others via the internet. In short, a computer can be described as a versatile machine that performs various tasks on behalf of humans.
Computers come in various forms. The most common types are desktop computers, which are typically placed on a desk, and laptops, which offer high portability. Recently, most people use smartphones, which combine portability with powerful computing capabilities, enabling them to perform an increasing number of tasks. Since smartphones can perform most of the same tasks as computers—just like desktops or laptops—they can be considered a form of computer rather than simply a phone.
Computers, which perform various tasks and exist in diverse forms, can be broadly categorized into five main functions: input, processing, memory, output, and control.
First, the input function works like the sensory organs of the human body to receive information from the outside world. A user must input the information necessary for the computer to perform calculations, such as what commands to execute or what data to process. The form of input varies depending on the input device. Letters and numbers can be entered via a keyboard, and a mouse can be used to select or manipulate information on the screen. Additionally, a scanner can be used to input documents or photos into a computer, or images captured by a digital camera can be imported. Information can be transmitted through various input devices such as OMR, OCR, joysticks, trackballs, and touchpads.
Recently, advancements in sensors have made even more diverse input methods possible. For example, a temperature sensor can be used to input the current temperature, or an accelerometer can detect the computer’s tilt. On smartphones, input is performed by directly touching the screen via a touchscreen, which serves as a substitute for mouse clicks.
When a user issues a command via an input device, the computer performs the corresponding operations. This computational capability is one of the core functions of a computer, and the CPU (Central Processing Unit) primarily handles this role. The CPU is a device that controls all computer operations and performs necessary computations, much like the human brain. Computers perform computations using machine language, which consists mechanically of 0s and 1s. The CPU interprets this machine language and performs the computations; the CPU’s performance is sometimes measured by the number of instructions it can process per second. For example, the unit MIPS (Million Instructions Per Second) indicates the CPU’s ability to process millions of instructions per second.
If we consider the process of a person performing an addition, when given the instruction to add 15 and 23, they must remember these numbers in order to perform the calculation. Computers also use memory functions to perform calculations. A device called memory handles this role, and memory can be divided into primary storage and secondary storage. Primary storage temporarily stores the instructions and data needed for calculations, while secondary storage stores data long-term. Primary storage is very fast but has a small capacity, whereas secondary storage is slow but boasts a large capacity.
Common examples of secondary storage include hard disks, flash memory, and, more recently, cloud storage.
Next, the process of outputting the calculation results to an external device is required. The results must be outputted so that others can understand them. For example, a monitor displays the results on a screen, a printer outputs the results as a document, and a speaker conveys the results through sound. The output function plays a crucial role in all these processes. Input and output devices are often grouped together and referred to as I/O devices, which enable interaction between the computer and the user.
Finally, the control function manages the entire system to ensure that each of the computer’s functions operates smoothly. The CPU consists of an arithmetic unit and a control unit; the control unit interprets instructions stored in main memory and manages the computer’s functions so that they operate in harmony. Through the control function, the computer can efficiently handle even complex tasks.
As described above, computers perform various tasks through five functions: input, processing, memory, output, and control. Computers originally began as calculators designed to quickly process complex calculations, but as these five functions evolved, they have established themselves as general-purpose machines that perform a wide range of tasks on behalf of humans. Today, computers allow us to manage nearly every aspect of our lives more conveniently and efficiently.
