(1) The document discusses the various hardware components that make up a computer system. This includes components like the power supply, motherboard, CPU, memory, hard drive, sound card, graphics card, network interface card, modem, floppy drive, optical drive, display, keyboard, mouse, speakers, printer, and video devices. (2) Memory devices like USB flash drives and memory cards are also covered, along with card readers that allow interfacing memory cards with computers. (3) Each component has a specific function, like the power supply providing power, the motherboard connecting components, the CPU processing data, memory temporarily storing data, and input/output devices managing interaction.

1. Computer hardware
(1) Power: Power supply indispensable in the computer equipment, its role is to convert the
220V AC power for the computer to use 5V, 12V, 3.3V DC, its performance is good or bad,
directly affect the work of other equipment stability, and thus affect the stability of the
machine.
(2) motherboard: motherboard is a platform for the various components of the computer work it
to the various components of the computer closely linked, the various components for data
transmission through the motherboard. In other words, the computer an important transport
hub on the motherboard, the stability of its work affects the stability of the whole work.
(3) CPU: The CPU (Central the Precessing Unit) central processing unit is the core of computing
and control core of a computer. Its main function is to explain the data in the computer
instruction and dealing with computer software. By the arithmetic unit, the CPU controller,
registers, cache and data links between them, control and status bus structure. As the core of the
system, the CPU is also the entire system execution units, so the CPU has become the core
component to determine the computer's performance, many users are using it as a standard to
determine the grade of the computer.
(4) Memory: memory, also known as the internal memory or random access memory (RAM),
divided into DDR memory and SDRAM memory (SDRAM due to low capacity storage is slow, poor
stability, but now has been DDR eliminated) belongs to the electronic memory storage device,
which consists of circuit boards and chips, is characterized by small size, speed, power can be
saved without electricity emptied, the computer can store data in memory when switched on,
the shutdown will automatically clear which all data. Memory DDR, DDR II, DDR III three
categories, capacity 1-8GB.
(5) Hard Drive: hard disk belonging to the external memory is made by the metal floppy disk,
floppy disk have in mind functions, so the reservoir to the data on the disk, regardless of the boot
or shutdown, all is not lost. Hard disk capacity now stands at TB level, size 3.5 inches, 2.5 inches,
1.8 inches, 1.0 inches, interfaces, IDE, SATA, SCSI, etc., SATA is the most common.
Mobile hard disk hard disk storage media, emphasizing the portable storage products. The vast
majority of the market for mobile hard disk is a standard hard drive-based, and only a very small
part is a miniature hard disk (1.8-inch hard drive, etc.), but the price factor determines the
mainstream mobile hard disk or to a standard notebook hard drive . With hard disk storage
media, removable hard disk read and write data model with standard IDE hard disk is the same.
The removable hard disk to use more transmission speed interface such as USB, IEEE1394 high
speed data transmission system.
(6) Sound Card: Sound card is composed of a hardware device for multimedia computers is
essential, its role is to play command is issued, sound cards, computer sound digital signal

2. converted to analog signals to the sound on the speakers.
(7) graphics card: graphics card and monitor at work with the role of output graphics, text,
graphics will display the information needed by the computer system conversion-driven, and the
line scan signal to the monitor, control the correct display of the monitor is connected to the
display and important components of the PC motherboard, is one of the important equipment of
the man-machine dialogue ".
(8) NIC: NIC is working in the data link layer, network components, is the LAN interface to connect
the computers and transmission media, not only able to match with the physical connection
between the LAN transmission medium and electrical signals, and also involves the frame
sending and receiving frame package and unpack, MAC, data encoding and decoding, and data
caching functionality. Network card to act as a bridge between the computer and the network
cable, it is the one used to establish the Department's website and important equipment
connected to the Internet. Often integrated motherboard sound card, graphics card, network
card part or all integrated on the motherboard.
(9) Modem: English called "Modem", commonly known as "cat", that is the modem. Is one of the
essential equipment in the Internet through the telephone line. Its role is to computer processing
on the digital signals into analog signals of the telephone line transmission. With the popularity
of ADSL broadband, the modem is gradually withdrawn from the market.
(10) floppy: floppy drive to read the data in the floppy disk. The floppy disk can read and write
external storage device connected with the motherboard FDD connector. Has been eliminated.
(11) Optical Drive: computer machines used to read and write CD content, is also more common
in desktop and notebook portable computer parts. As multimedia applications more widely,
making the CD-ROM drive in computer accessories has become the standard configuration. At
present, the CD-ROM into the CD-ROM drive, DVD drive (DVD-ROM), Combo (COMBO) and the
burner and so on. The capacity and speed of reading and writing is also rising, 4 × 16 × 32 × 40 ×
48 ×.
(12) Display: Display some small, thin, with thick, species diversity, its role is to display the results
of computer processing. It is an output device, component of the computer indispensable.
Divided into the CRT, LCD, LED three categories, the interface has two types of VGA, DVI.
(13) Keyboard: The keyboard is the main input device is usually 104 or 105, for text, digital output
to the computer.
(14)mouse: When people move the mouse on a computer screen will move with an arrow pointer,
and can be very accurate cut refers to the wish to refer to their position on the screen positioning,
it is the way people use computers is indispensable one of the components. The keyboard and
mouse PS / 2 and USB interface. Hardware mouse is divided into two kinds of optical and
mechanical (mechanical photoelectric eliminated)

3. (15) Speaker: audio cable connected to the power amplifier, and then through the transistor to
amplify the sound output to the speaker, so that the speaker issued a computer voice. Computer
speakers can be divided into these types of 2,2.1, 3 .1,4,4.1,5.1,7.1. The sound quality varies.
(16) printer: it can print the file in your computer to paper, it is one of the output device. Formed
in the printer field, dot matrix printers, inkjet printers, laser printers, the three pillars of
mainstream products, each play to its advantages, to meet the different needs of the user
community.
(17) video devices such as cameras, scanners, digital cameras, digital cameras, TV cards and other
equipment for the processing of video signals.
(18) memory disk
Flash drive is usually known as USB flash drives, USB flash disk, flash drives, a Universal Serial Bus
(USB) interface without the physical drive the miniature high-capacity mobile storage products,
storage media it uses flash memory storage media (Flash Memory). The flash drive is generally
include flash memory (the Flash Memory), control chips and shell. The flash drive has the
advantage of repeatedly rewritable speed and anti-magnetic, shock, moisture. Popular flash drive
using the USB interface, size is only thumb size, weighing about 20 grams, do not drive, no
external power, plug and play to achieve the exchange of documents between different
computers, storage capacity ranging from 1 ~~ to 32GB to meet different needs.
(19) mobile memory card and card reader
Memory card is the use of flash memory (Flash Memory) technology to store electronic
information storage, generally used in digital cameras, handheld computers, MP3, MP4, and
other small digital products as a storage medium, so look small, like a card, so termed for flash
memory cards. According to different manufacturers and different applications, flash memory
cards SmartMedia, (SM Card), Compact Flash (CF card), Multi Media Card (MMC card), Secure
Digital (SD card)
, Memory Stick (Memory Stick), the TF card and other types of these flash memory card
appearance, specifications, but the principle is the same technology. Since the flash memory card
can not be direct computer to identify, the reader is a both a bridge. Card Reader Card Reader)
you can use a variety of memory card such as Compact Flash or Smart Media or the Microdrive
storage cards, access to the device as a storage card information. Reader USB1.1/USB2.0 the
transmission interface, hot-swappable. Ordinary USB device, just plug in the computer's USB port,
then plug the memory card can be used. Divided according to the speed of USB1.1 and USB2.0,
classified by purpose, a single reader and multi-card reader.