計算機概論

2013年4月27日星期六

4/19 Input 輸入

Input 輸入

-->Data or instructions entered into memory of computer

Two types of input : Data & Instruction

The Keyboard 鍵盤

The Keyboard
-->Typing area
-->Numeric keypad
-->Function keys,special keys that issue commands

Key combination

insertion point 游標
-->Blinking vertical bar that indicates where next character you type will display

Pointing Devices

mouse 滑鼠

-->Pointing device that fits under palm of hand

Other Pointing Devices

trackball軌跡球

touchpad觸控板 pointing stick

joystick搖桿

touch screen觸控式螢幕

graphics tablet繪圖板 stylus畫筆

Voice Input

MIDI(musical instrument digital interface)

-->External device, such as electronic piano keyboard, to input music and sound effects

PDAs,Tablet PCs,and Smart Phones

Digital Cameras

digital camera

-->Allows you to take digital pictures

-->Images viewable immediately on camera

resolution

-->Sharpness and clarity of image

-->>The higher the resolution,the better the image quality,but the more expensive the camera

Video Input

video input

-->Process of entering full-motion images into computer

-->Video capture card is adapter card that converts analog video signal into digital signal that computer can use

-->Digital video(DV)camera records video as digital signals

PC video camera and Web cam

video conferencing 視訊會議

-->Two or more geographically separated people who use net work on Internet to transmit audio and video data

Scanners and Reading Devices

scanner 掃描機

-->Light-sensing device that reads printed test and graphics

OCR(Optical character recognition)光學字元辨識
-->讀取紙張文件中的字元

OMR(Optiacl-mark reader)光學記號閱讀機
-->讀取手繪的記號，例如小圓圈或矩形

bar code 條碼

Terminals

point of sale(POS) terminal

-->Records purchases processes credit or debit card,and updates inventory
automated teller machine(ATM)
-->Self-service banking machine that connects to a host computer through a network
smart display
-->Thin monitor that detaches from computer to function as portable wireless touch screen

Biometric Input

biometrics

-->Authenticates person's identity by verifying personal characteristic

ex.fingerprint scanner

2013年4月25日星期四

3/29 The Components of the System Unit

System unit
--> Case that contains electronic components of the computer used to process data

Chips
-->Small piece of semi-conducting material on which integrated circuits are etched
-->Chips are packaged so they can be attached to a circuit board

Motherboard
-->Main circuit board in system unit
-->Contains adapter card,processor chip, and memory chips
-->Also called system board

Machine cycle
-->Four operations of the CPU comprise a machine cycle

FOUR STEPS
1.FETCH 擷取
2.DECODE 解碼
3.EXECUTE 執行
4.STORE 寫回

Pipelining 管線作業
-->CPU begins fetching second instruction
before completing machine cycle for first instruction
-->Results in faster processing

Register 暫存器
-->Temporary high-speed storage area that holds data and instructions

Memory
--> Electronic components that store instructions, data ,and results
--> Consists of one of more chips on motherboard or other circuit board
--> Each byte stored in unique location called address, similar to seats on a passenger train

Random access memory(RAM) 隨時存取記憶體(又稱揮發性記憶體)
-->Memory chips that can be read from and written to by processor
-->Also called main memory or primary storage
-->Most RAM is volatile (揮發性), it is lost when computer's power is turned off
--> SRAM DRAM

Read-only memory (ROM) 唯讀記憶體
-->Memory chips that store permanent data and instructions
-->Nonvolatile memory, it is not lost when computer's power is turn off

Access time 存取時間
-->Amount of time it takes processor to read data from memory
-->Measured in nanosecond (ns)

記憶體奈秒
硬碟毫秒
記憶體速度快

2013年3月28日星期四

3/22 錯誤更正漢明碼 CPU

錯誤更正漢明碼 16 bit

CPU中央處理器（英語：Central Processing Unit，縮寫：CPU），是電子電腦的主要裝置之一。其功能主要是解釋電腦指令以及處理電腦軟體中的資料。電腦的可編程性主要是指對中央處理器的編程。中央處理器、記憶體和輸入／輸出裝置是現代電腦的三大核心部件。20世紀70年代以前，中央處理器是由多個獨立單元構成。後來發展出由積體電路製造的中央處理器，微處理器中央處理器複雜的電路可以做成單一微小功能強大的單元。

控制單元 4 STEPS
擷取(Fetch) --> 解碼 (Decode)--> 執行(Execute) --> 寫回(Store)
Pipelining 管線作業 in fast processing

1.算術邏輯單元(ALU)
在多數情況下，真正負責執行指令的是CPU的算術邏輯單元(ALU)。
2.匯流排單元
負責CPU與記憶體之間的溝通。
3.預先擷取單元
負責告訴匯流排單元到哪個記憶體位置讀取指令,而且他不僅會擷取下一個要執行的指令,而且她不僅會擷取下一個要執行的指令,還會擷取後續的其他指令,以確保要執行的指令都已經準備好了。
4.解碼單元(decode unit)
負責從預先擷取單元取得要執行的指令,並轉譯成CPU內部可以處理的形式。他會在控制單元中找尋要完成目前指令所需要的步驟。