本文是计算机专业的留学生作业范例，题目是“Purpose Of Computer Components Computer Science Essay（计算机组成的目的计算机科学论文）”，计算机内部有许多外围设备，它们通过总线/电线与其他硬件/软件进行指令处理。这些都是硬件一起工作，并显示输出/输入。如“主板”、“显示器”、“操作系统”、“键盘”、“鼠标”、“扬声器”、“CPU(中央处理器)”、“硬盘(存储设备)”和“图形卡/视频卡”。
There are many peripherals inside computer base, which process instruction via buses/wires to other hardware/software. Those are hardware’s that works together and shows output/input. Such as “Motherboard”,” Monitor”, ” Operating system”, “Keyboard”, “Mouse”, “Speakers”, “CPU (Central Processing Unit)”, “Hard Disk (storage devices)” and “Graphic card /video card”.
My aim is to describe about hardware, role of hardware and specification. Nowadays, technology growing very fast, even mobile, PDA works as computer, without having hardware like computer. In this report, the user will get more knowledge about hardware. The CPU is main device to maintain and provides order to RAM. If we go to deep then, the CPU has for factor of execution, such as PC (program controller), CU (control unit), and ALU (arithmetic logic unit) and finally is storage (registers).
1.Central processing unit (CPUs) 中央处理器(cpu)
This memory is registered with functions; the most important program is program counter (PC), which indicates to next command to be executed. And also there is another register which contains instruction of current processing task. A CPU needed a motherboard and RAM to transmit instructions and Ventilation sink to cool down the CPUs internal materials (buses).
CPU processing cycle: it is execution process where the instructions processed by sequentially within CPU from memory. A cycle mean it keep reaping and executing instructions until a task is finished or reached.
2.Primary memory and secondary memory 主要记忆和辅助记忆
RAM (random access memory) before in 2003, RAM shared 512 memory that provided by system but nowadays RAM memory reach up to 1 or 4 GB, when RAM is not capable to transmit the data flow within its ability, then the user might have install another RAM. So the system can run faster and task will be monitored by operating system. As we know that memory controls the signal traffic, but upgrading latest RAM, improves the traffic signal of data/task, works faster than before and also you will get quick response from computer system. Basically, memory is measured by increase of bits and bytes.
It stores data that can be access sequentially. If the data is not reached or not found at present position, than each memory bytes checked until get full information or found data. A SAM (serial access memory) is a partition of RAM that helps to transfer (buffer) data; organise data in order and then stores. A memory is integrated circuit (IC), which developed by 100 thousands of transistors and capacitors. Most basic RAM circuit is DRAM (dynamic memory random access memory). A capacitors and transistors produce a memory cell, which represents a signal bit of data (1 or 0). A capacitors is contains one signal digit at one time (voltage) and transistor works as switch, so it lets the control circuitry on the memory circuitry reads that binary words that capacitors contains and modify its position.
Memories consist of a cells and each cell organised by address. A CPU (central processing unit) interact with main memory by sending signals to two registers of memory, which are memory address register (MAR.) and memory buffer register (MBR). When a CPU wants instruction from memory, it sends address of instruction to MAR and send digital frequency to memory the memory. After that the memory stats functioning and insert that instruction to MBR, where the CPU can access that frequency. The CPU set the address into MAR and cells are stored in the MBR. Finally, the memory is starts working and store set of instruction. A memory needs slots to locate into motherboard. The user can input two memory chipset at one time. There are two type of chipset which are DDR and SDRAM, its sends instruction twice at same time.  A program only launch from main memory and OS (operating system) holds instruction until needed.
3.Hard drive 硬盘
Today, the hard drive is available in various formats, such in larger capacity. It used to hold up permanent data such as operating system, files and application. A disk is made from metal or made from special glass or aluminium or alloy material, which is LP phonograph used to record. The user can save large amount of data for permanent. A memory does not disappear when computer is shutdown. It holds memory until user needs. A hard disk is holds bytes and bit and that converted into file/folder. However, when program is running that moment the hard disk retrieves instructions and sends data to CPU at the one time. Commonly, the hard drive is transmitting data between 5 to 40 Mbps. When a CPU request for data from hard drive, that time the data transmitted to CPU between 10- 20 milliseconds.
如今，硬盘驱动器有多种格式，比如更大的容量。它用来存放操作系统、文件和应用程序等永久性数据。唱片是由金属或由特殊的玻璃或铝或合金材料制成的，这是LP留声机用来录音。用户可以永久保存大量数据。当计算机关闭时，内存不会消失。它保存内存直到用户需要。硬盘保存字节和位，然后转换成文件/文件夹。然而，当程序运行的那一刻，硬盘检索指令，并发送数据到CPU在同一时间。一般情况下，硬盘传输速率为5 ~ 40mbps。当CPU从硬盘请求数据时，数据传输到CPU的时间在10- 20毫秒之间。
Information is printed on a patterns and tracks. Track means concentric circles and patterns are in pie shaped. The disk has hundreds of tracks per shell. There are data reader head that move to closer or move back to central. The head is long enough to read or write data from whole CD, when it’s spinning. A hard drive have many disk installed vertically by inch apart and every disk patterns have a head that movies together and executes data at same time. Each disk drive has installed with “disk controller. The controller transmits data between main memory and disk. Once a data start executed, the memory set the address for that data and keep information about where to go? And keep address of data that executed from. A disk have many sectors are divided by tracks, basically, 10 to 100 sectors per track.
Disk storage and USB storage: A disk is third memory storage device because the user can take anywhere. A DVD drive is rewritable compact disk knowledge. A user can save data from hard drive or load the data into it for purposes. It is burns various type of disk in different formation such as music, video and file. There also external DVD drives that can be connect via wire. A DVD drive data read rate is 48* (CD) and 16* (DVD); also writing rate is 48* (CD), 6-8 * (DVD) and 12* (DVD RAM). A user need a disk drive that record data into disk, but in DVD drive a laser reads data from surface of disk and then transmitted into computer system. A purpose of the “Disk” is to backup data and for protection.
A USB (universal serial bus) devices are very easy to use and a device created for universal use, because a small chipset, it can store large data. It usually works in any computer or other device and range of components can be connected easily. A USB 1.1 has ability to transfer maximum rate of1.5 – 12mbps.
4.Keyboard, Mouse 键盘、鼠标
A keyboard is very common hardware to input/guide instruction and for manage computer system. It can connect via wire or USB ports. It has many characters to interact with PC, such as numbers, symbols and alphabets. It has switches to translate the person who type character into bytes so computer can understand. Most of keyboards have 80- 110 keys including functional key, control key, numeric pad and typing keys. Inside the keyboard, it has own circuitry and processor to take instruction to CPU.
A mouse is best model to interact with computer system without typing in; control censor movement and have ability to point on the object on computer monitor. It gives you easy accessibility to perform function of computer system. A mouse (device) installed with either sensor or roll ball to create/navigate motion. There are different mouse developed which is optical, touchpad and roll ball. An optical mouse has track sensor (CMOS: complimentary metal-oxide semiconductor) that scan surface and does not need a pads to support. The CMOS sensor transmits every collected image to digital signal processor (DSP) for analysis. Basically, a DSP measured the collection of data that how patterns are moving from previous image.
Motherboard is main part of the computer and it handles communications between devices via transmitting electromagnetic power. A motherboard has many supports components to hardware, such lithium betray, DDR memory slots, 12v ATX power connector, AGP slots, chipsets, USB headers, PCI slots, CPU, HDD headers, IEEE (network) etc. Each function of motherboard has own responsibility to support internal hardware.
There are many comprised individual circuit traces that is in collection of form of buses. Traces are skinny conductors or circuits on motherboard that works combine for a specific aim. It transmits electrical frequency (signals) from HDD, CPU and RAM then to other devices. A motherboard “Bus” is work with internal chipset/circuit to move exist data within motherboard. A motherboard can be process 32/64 bits, and transmit data up to 800-2000 MHz Major functions of the motherboard is chipset which is north and Southbridge; usually, it behave as traffic signals on the motherboard to measure high and low voltage communication to reduce data crashes. A Northbridge manages high speed communication between CPU, Ram and supportive hardware but Southbridge manages slow speed of communication based device between ports and slots, such as USB, IDE, parallels, serial, keyboard etc.
6.Graphic card 图形卡
A graphic card is provides supportive abilities for media bases software or hardware to work and run properly. Specially, an Intel chipset (G965, GM965, G33 etc) developed to support games animation, high resolution, and GUI (graphical user interface). A graphic card is allowed to experienced high definition GUI without needed for add-in components. Most of the graphic card is installed within motherboard’s AGP slot. A role of GPU (graphic processing unit) is to draw entities (geometric and mathematic calculation) that moving fast image that observe the monitor and its high level of language produce for graphic interface. To target that real time animation, the GPU must perform much floating-point operation per second. A GPU measured a shape and type of data and passes to execute function at GPU . A GPU modelled by vector processing modelled, to support high application and support their functionally and GPU parallel architecture allows to perform faster, boosting rate of execution.
A manufacture developed much kind of GPU and to support; the user needs to install drivers. Currently, there are two type of GPU interface, which is OpenGL and DirectX [ref]. Because, those are interfaces developed for programming graphic operations.Reason I wrote about GPU because it has big responsibility give graph card to support other elements. An image we see on the monitor, it is tiny dots of pixels and that pixels are common regulation setting; each block of cells has thousands of pixels. Graphic card is translator binary data from CPU and convert into image. Basic principal of CPU is to transmit instruction that provided by software and graphic card decides how much pixels have to use to describe image. After that it transmits information to the monitor through cables. It also contains output/input technology, such as memory, processor, heat sink, motherboard connector.
A scanner scans paper based information and converted into image, but that image, a printer prints it. The advantage of having scanner is to keep data in digital way and when it needed data will printed. A purpose of mouse is to interact and select object from monitor, so without inputting, a system going to run much easier. But a keyboard has many symbolic buttons and each buttons are address by bytes which keyboard processor convert into binary and transmitted to CPU. A motherboard developed by many functions to support and provide communication channel to hardware’s which is connected to. Basically, it transmits an electric power via system buses and Northbridge manages high speed of CPU, RAM and ROM but Southbridge manages high speed of external devices, such as secondary and optic memory. A graphic card has important role as well to provide clear and sufficient image on the monitor. GPU is measures complex geometric shape and do mathematical calculation to make GUI (graphical interface system) system.