Overview of Computers

An electronic calculator that performs complex operations on behalf of people.
It can store and manage large volumes of data.

Characteristics of Computers

Speed: Computers can process large volumes of data. Modern computers perform billions of arithmetic operations per second.
Reliability: Computers support reliable, error-free processing of large amounts of data. This is essential when computers take over human work.
Accuracy: Thanks to rapid advances in semiconductor technology, computer accuracy continues to improve.
Data preservation: With the development of storage devices for preserving many kinds of data, a significant amount of data can be accumulated and stored in a small space.
Economy: By processing large volumes of data quickly, computers reduce time and cost compared with human work.

PC (Personal Computer)

Early computers were not designed for independent personal use. They were developed for shared purposes and were divided into central computers with central processing units and memory devices, and terminals for users. A PC is a computer developed for independent personal use. It combines the central processing unit, memory, and input/output devices that a computer needs into a single product.

Hardware and Software

Hardware

Hardware means physical devices. A computer contains many kinds of hardware, such as the CPU, memory, disk drives, and input/output devices. These devices operate according to software instructions.

Software

Software means the programs that run on a computer and perform work. Operating systems, games, graphics programs, educational programs, and business programs are examples of software.

Basic Terms

bit and Byte

Computers use digital electrical signals that represent all data as 0s and 1s. Digital data represents information using only two electrical states: “1”, where electricity flows, and “0”, where it does not. This is the bit, the smallest unit of data representation in a computer. In other words, 1 bit can represent only two values: 1 and 0. However, this alone is not enough to convert human characters into computer data. Combining two electrical signals can represent four values: 00, 01, 10, and 11. This still cannot represent human characters sufficiently, so 8 bits are combined. When 8 bits are combined, 256 different data values can be represented. This is called 1 byte. Ultimately, this is the amount of data used to represent one character, such as an English letter. 1 byte consists of 8 bits.

Bus

In a computer, a bus is a transmission path for delivering data. Computers may be classified by the structure of this path. It also refers to the width of data that can be exchanged at one time between the CPU and peripheral devices. It starts with 8 bits and has developed through 16 bits, 32 bits, and 64 bits.

History of Computers

ENIAC, the First Computer

In 1944, Aiken, a professor at Harvard University, built “MARK-1” with sponsorship from IBM. Although “MARK-1” could not be called a true computer, in 1946 Mauchly and Eckert at the University of Pennsylvania developed a military computer used for ballistic tables, weather forecasting, atomic energy calculations, and cosmic ray research. This was ENIAC, which used a decimal system.

ENIAC was made to calculate using vacuum tubes. It had as many as 18,000 vacuum tubes and 6,000 switches, so it was large and very difficult to operate. In addition, because programs were not compatible, changing a program required reconnecting all those switches from the beginning.

EDSAC, the Stored-Program Computer

In 1949, Maurice Wilkes completed EDSAC, the first computer with a stored program. In 1951, a computer called EDVAC, again using the binary system, was developed by von Neumann. IBM also developed UNIVAC 1, which used magnetic tape as auxiliary storage, and installed it at the United States Census Bureau.

Computer Generations

Generation	Years	Central Processing Unit	Main Memory	Programming Language
1st generation	1946-1957	Vacuum tubes	Magnetic drum	Assembler
2nd generation	1958-1964	Transistors	Magnetic core	FORTRAN, COBOL
3rd generation	1965-1974	IC	Magnetic disk	Pascal, BASIC
4th generation	Since the 1970s	LSI	Semiconductor	Modern programming languages
5th generation	Present	VLSI	Semiconductor	Modern programming languages

Structure of a PC

Central Processing Unit (CPU)

It contains a control unit that operates each device in the computer and controls normal operation.
It contains an arithmetic unit that processes various computational data.
It contains registers for temporarily storing data.
It determines computer performance and the type of system.

Input Devices

Devices that receive commands and data from the user. Keyboards and mice are examples.

Output Devices

Devices that deliver the results processed by the computer to the user. Monitors and printers are examples.

Storage Devices

Devices where the operating system and various programs are installed and where data created by users is stored.
Hard disks, CD-ROMs, and CD-RWs are examples.

Peripheral Devices

Devices that are not necessary for basic computer operation and management but are added when needed are called peripheral devices.
They can improve user convenience.
LAN cards, sound cards, mice, printers, and joysticks are examples.

Controllers

Controllers manage smooth data flow between devices and detect errors.
They determine the connection method for peripheral devices.
When implemented as hardware, the term “controller” is used.
When implemented as software, a program installed to operate hardware is called a “driver”.