Introduction to Computers

What is a computer:
    A computer (电脑) is a modern electronic computing machine used for high-speed calculation. It can perform
    numerical computations, logical computations, and has storage and memory functions. It is a modern
    intelligent electronic device capable of running programs automatically and processing massive amounts
    of data at high speed.

Components of a computer:
    A complete computer system consists of two major parts: hardware and software. Hardware refers to the
    various physical devices in a computer system. Software refers to all the programs required for the
    computer to operate.

CPU:
    The CPU (Central Processing Unit) is the computational core and control core of a computer.

Graphics Card:
    The graphics card works with the monitor to output graphics and text. Its function is to convert and
    drive the display information required by the computer system, providing horizontal scan signals to the
    monitor to control correct display. It is an important component connecting the monitor and the
    computer's motherboard, and is one of the key devices for "human-computer interaction."

Memory (RAM):
    Memory is also called internal storage or Random Access Memory (RAM).

Sound Card:
    The sound card is an indispensable hardware device for a multimedia computer. When a playback command
    is issued, the sound card converts digital audio signals from the computer into analog signals and
    sends them to speakers to produce sound.

Motherboard:
    The motherboard is the platform on which all components of the computer work. It connects all parts
    of the computer closely together, and data is transmitted between components through the motherboard.
    In other words, all the important "traffic hubs" of a computer are on the motherboard, and its
    stability affects the overall stability of the machine.

Network Card:
    The network card is a network component that operates at the data link layer. It is the interface
    between computers and transmission media in a local area network (LAN). It not only achieves physical
    connection and electrical signal matching between the computer and the LAN transmission medium, but
    also handles frame sending and receiving, frame encapsulation and decapsulation, media access control,
    data encoding and decoding, and data buffering. The network card acts as a bridge between the computer
    and the network cable, and is one of the key devices for establishing a LAN and connecting to the Internet.

Hard Disk:
    The hard disk is an external storage device. Mechanical hard disks are made of metal magnetic platters,
    and the magnetic platters have memory functions, so data stored on them will not be lost whether the
    computer is on or off. Hard disks have very large capacities, already reaching TB levels. Sizes include
    3.5, 2.5, 1.8, and 1.0 inches, and interfaces include IDE, SATA, and SCSI, with SATA being the most
    common. External hard drives use hard disk storage media and emphasize portability.

Definition:
    Software is a series of computer data and instructions organized in a specific order; it is the
    intangible part of a computer.
    Software is an abstract product composed of program code in a computer.
    We generally divide computer software into two major categories: system software and application software.

Application Software:
    Generally refers to various types of software that can directly help individuals or organizations
    complete specific tasks, such as word processing software, computer-aided design software, information
    management software for enterprises and institutions, and game software. Application software generally
    cannot run independently on a computer and must be supported by system software. The most fundamental
    type of system software that supports application software is the operating system. Application software,
    especially various specialized software packages, is often provided by specialized software vendors.

System Software:
    System software refers to software that manages, controls, and maintains the computer and its peripheral
    devices, and provides an interface between the user and the computer. Compared to application software,
    system software is closer to the computer system hardware and farther from the problems that users care
    about. It is not specifically targeted at particular application problems.

An operating system can control and coordinate all components of a computer to work together.
Therefore, when you buy a computer in a store or mall, they will assemble the computer for you and
install an operating system — commonly known as Windows XP, Windows 7, Windows 10, etc.

Common Operating Systems:
    Windows — rich graphical interface, paid, large number of tools, suitable for personal office use.
        Windows XP
        Windows 7
        Windows 10
        Windows Server

    Linux — good performance, low resource usage, suitable for use as a server.
        CentOS
        Ubuntu
        Red Hat
        Deepin

    macOS — humanized interaction, beautiful and easy to use, suitable for personal use.

After installing any of the above operating systems, users can perform operations on the computer
using mouse, keyboard, touchscreen, etc. The operating system responds to user actions to control
the various hardware components of the computer, thus helping us complete tasks.

Note: Operating systems are also developed by programmers.