Software (in Chinese mainland and Hongkong, made in Taiwan Province Province) is a series of computer data and instructions organized in a specific order. Generally speaking, software is divided into system software, application software and middleware between them. Among them, the system software provides the most basic functions for computer use, but it is not aimed at a specific application field. On the other hand, application software provides different functions according to users and their service fields. Software includes not only programs that can be run on a computer, but also files related to these programs are usually considered as a part of software. Software has been applied in all fields of the world, which has a far-reaching impact on people's lives and work. System software System software is responsible for managing all kinds of independent hardware in the computer system so that they can coordinate their work. System software enables computer users and other software to regard the computer as a whole, regardless of how each underlying hardware works. Generally speaking, system software includes operating system and a series of basic tools (such as compiler, database management, memory formatting, file system management, user authentication, driver management, network connection and other tools). Application software Application software is software developed for a specific purpose. It can be a specific program, such as an image browser. It can also be a group of programs with closely related functions that can cooperate with each other, such as Microsoft Office software. It can also be a huge software system composed of many independent programs, such as a database management system. According to the operating system, there are Word processing software such as WPS and Word, and information management software such as AutoCAD real-time control software and educational entertainment software. BeOS DOS Linux Mac OS Unix Windows software development software development is a process of building a software system or software parts in the system according to user requirements. Software development is a systematic project, including requirements capture, requirements analysis, design, implementation and testing. Software is usually implemented in programming languages. Software development tools can usually be used for development. Hardware Generally, the computer we see consists of a host (main part), an output device (monitor) and an input device (keyboard and mouse). The host computer is the main body of the computer. In the main chassis, there are: motherboard, CPU, memory, power supply, graphics card, sound card, network card, hard disk, floppy drive, CD-ROM and other hardware. Basically, a computer can be divided into five parts: arithmetic unit, memory, controller, input device and output device. Next, we will unveil their mystery step by step. (1) Chassis First, let's look at the chassis. In addition to creating an external image for the computer system, the chassis also provides mounting brackets for other accessories of the computer system. In addition, it can reduce the electromagnetic pollution radiated from the inside of the chassis to the outside, protect the health of users and the normal use of other equipment, and it can really be called the "home" of computer accessories. AT present, the mainstream product on the market is the vertical chassis with ATX structure, and the chassis with AT structure has been eliminated. Inside the chassis, there is a bracket for installing hard disk, CD-ROM drive and floppy drive on the front panel side, and there is a position for installing power supply on the upper part of the back panel side. In addition, some wires are connected to the wind part of the chassis for connecting the power key, rest key, PC speaker and some indicator lights. Its internal structure is shown in the figure. (2) Motherboard Motherboard (English name Mainboard or motherboard) is the largest circuit board in a computer system. Motherboard is also called motherboard, system board or motherboard. It is installed in the chassis and is one of the most important parts of the microcomputer. Its type and grade determine the type and grade of the whole microcomputer system. It can be divided into AT motherboard and ATX motherboard. The motherboard consists of various interfaces, expansion slots, sockets and chipsets. The basic strategy of motherboard selection: speed, stability, compatibility, expansibility and upgrade ability. The chipset in the motherboard is the core of the motherboard, and its function is to establish a reliable and correct installation and operation environment for CPU, memory stick, graphics card and other components in the microcomputer system through the motherboard under the control of BIOS and operating system, and to provide convenient and reliable connection interfaces for various ide interface storage and other external devices. Common motherboards are as follows (3) CPU CPU (Central Processing Unit) is one of the most important parts of a computer. It is the core of the computer, equivalent to the human brain. Its internal structure is divided into three parts: control unit, logic unit and storage unit. The interface standard of CPU is divided into two categories: one is socket type and the other is slot type. Its main performance indicators: main frequency, front-end bus frequency, capacity and speed of L 1 and L2Cache, supported extended instruction set, CPU core working voltage address bus width, CPU selection and purchase. There are two main manufacturers of CPU: Inter and AMD, among which Inter's CPU products have the highest market share. The mainstream CPUs in the market are: Pentium III series, Pentium 4 series and Celeron series of Intel Corporation; AMD's K7 series. (4) Memory Memory generally refers to a semiconductor storage unit used to store data and instructions in a computer system. According to the purpose, it can be divided into main memory and auxiliary memory. According to the working principle, it is divided into ROM and RAM. ROM can be divided into read-only ROM, programmable erasable ROM and programmable ROM, while ram can be static and dynamic ram. Memory (RAM) is the productivity of CPU in processing information, and its calculation unit is megabyte MB, that is, megabyte. 1 byte consists of 8-bit binary numbers (0, 1). Store 1 English letters 1 bytes. However, it takes 2 bytes to store 1 Chinese character. Early computers mainly run D05 system and DOS program. At that time, the memory price was very expensive, and DOS didn't require much memory, as long as it was 640KB( 1KB= 1024B), so the computer memory at that time was not very large, 1MB or 2MB would be fine. Now the price of memory has been greatly reduced, but Windows and some new applications are insatiable for memory. The larger the memory, the better the effect. Therefore, the 64MB memory of the juice computer is the minimum configuration. If you have money, I hope it matches 128MB or even 5 12MB. At present, the well-known brands are Hyundai (Hyundai original factory), Kingstone (Kingston), Kingmax (Shengchuang), Samsung (Samsung), Chuangjian (original factory) and CEIL (Golden List). (5) The hard disk is an important storage device of the computer system, and its performance directly affects the overall performance of the computer. Hard disk is a fixed storage device, and its storage medium is several hard disks. Its characteristics are: high speed, large capacity, high reliability and almost no wear problem. At present, there are two common hard disk interfaces, namely IDE interface and SCSI interface. Hard disks with good reputation include Maituo, Seagate, IBM and Western Digtal. (6) CD-ROM is a tool for reading data on CD-ROM, which is characterized by large capacity, high speed, strong compatibility and low cost. 52 times the speed of IDE interface CD with mainstream. A floppy disk is an indispensable part of a computer. When necessary, it can help us start the computer, and it can also be used to transfer and back up some smaller files. 3.5-inch ones are commonly used now, and 5.25-inch ones were used in ancient times. Now we go to buy, they don't sell. (VIII) Graphics card The graphics card is the control circuit and interface for communication between the display and the host, and its function is to convert the digital signal of the host into an analog signal and display it on the display. The basic function of graphics card is to control the output of graphics. It works between CPU and monitor. Its main components are: display chip, RAMDAC, display memory, VGA BIOS VGA socket, functional connector, etc. Three important indicators of graphics card: refresh frequency, resolution and color depth. According to the bus type, there are four kinds of graphics cards: ISA, VESA, PCI and AGP. AGP display cards are very common now. The appearance is shown in the figure below. (9) sound card sound card, without which you can't listen to music. The computer transmits sound to the speaker through this thing. Sound card is one of the main components of multimedia computer, which contains the hardware needed for recording and playing sound. There are many kinds of sound cards with different functions, but there are some basic functions in common: you can record voice (sound) and music, you can choose mono or dual-channel recording, and you can control the sampling rate. The sound card has a digital-to-analog conversion chip (DAC) for converting digitized sound signals into analog signals and an analog-to-digital conversion chip (ADC) for converting analog sound signals into digital signals. The sound card has a music digital interface (MIDI) and can use MIDI instruments, such as piano keys, synthesizers and their MIDI devices. The sound card has a mixing function, which can control the size of sound source and audio signal. A good sound card can control the bass and treble parts. There is also one or several CD audio input interfaces on the sound card, which are used to receive the sound collection signal of CD-ROM. According to the different buses, sound cards can be divided into two categories, one is ISA sound card and the other is PCI sound card. The mainstream is the PCI sound card as shown in the figure below (10). The monitor is the main output device of the computer. Without it, we will become blind when dealing with computers. Maybe your job needs to face the computer screen every day, but do you really understand? Because of this, when buying a computer, many people only care about whether the monitor is 14 inch or 15 inch, and don't care about other performance of the monitor. In fact, the monitor is the last thing to save money when buying a computer. At present, there are many brands of monitors. The common brands in the market are Samsung, Sony, LG, Youpai, Philips, Acer, MAG and EMC. According to the imaging principle, displays can be divided into CRT display (cathode ray tube display), LCD display (liquid crystal matrix flat panel display) and plasma display. Among them, CRT display and LCD display are more common, and LCD display will be the mainstream in the next few years. The picture below shows an LCD monitor of Samsung. (1 1) Keyboard I think everyone should be familiar with it. I'll give you a brief introduction. Keyboard is the most commonly used and main input device. English letters, numbers, punctuation marks, etc. can be input into the computer through the keyboard, so as to send commands and input data to the computer. Since the advent of IBM PC, the keyboard has experienced 83 keys, 84 keys and101102 keys. After the advent of Windows95, on the basis of 10 1 keyboard, it was improved to 104/ 105 keyboard, and two keyboards were added. In order to make people operate the computer more comfortably, the "human keyboard" appeared. The shape of the keyboard is very consistent with the posture of both hands, and it is particularly easy to operate. (12) The mouse was first applied to the Apple computer. With the popularity of Windows operating system, the mouse has become a necessity, and some software can only run without the mouse. From the interface, there are two kinds of mice: PS/2 mouse and serial mouse. Judging from the structure of the mouse, there are mechanical and photoelectric types. The photoelectric mouse uses the reflection of light to determine the movement of the mouse, and there are infrared light emitting and receiving devices inside the mouse. In order to make the photoelectric mouse play a powerful role, it must be equipped with a special photosensitive plate. The positioning accuracy of optical mouse is much higher than that of mechanical mouse. In addition, the mouse can be divided into single button, two buttons and three buttons. Apple computers usually use a one-button mouse, a two-button mouse is usually called an MS mouse, and a PC mouse is called a PC mouse. However, whether the mouse is used with two keys or three keys depends mainly on the software. For example, for Windows 98 and Windows95 and their application software, the mouse can only be used for two keys, otherwise the computer will not recognize it, but some software can support the third key, such as AutoCAD.