計算機組成原理 經常使用名詞解釋

計算機組成原理

計算機組成原理概述

計算機概述

計算機的基本組成:

• 存儲器:　　　　　實現記憶功能的部件用來存放計算程序及參與運算的各類數據
• 運算器:　　　　　負責數據的算術運算和邏輯運算即數據的加工處理
• 控制器:　　　　　負責對程序規定的控制信息進行分析,控制並協調輸入,輸出操做或內存訪問
• 輸入設備:　　　　實現計算程序和原始數據的輸入
• 輸出設備:　　　　實現計算結果輸出

組成的聯繫:

• 圖一

圖二

馮·諾依曼機制:

• 程序存儲
• 採用2進制

計算機系統的體系結構:

• 圖一:

圖二：

總線：

定義:鏈接計算機各部件之間或各計算機直接的一束公共信息線,它是計算機中傳送信息代碼的公共途徑

總線（Bus）是指計算機組件間規範化的交換數據（data）的方式，即以一種通用的方式爲各組件提供數據傳送和控制邏輯。從另外一個角度來看，若是說主板（Mother Board）是一座城市，那麼總線就像是城市裏的公共汽車（bus），能按照固定行車路線，傳輸來回不停運做的比特（bit）。這些線路在同一時間內都僅能負責傳輸一個比特。所以，必須同時採用多條線路才能發送更多數據，而總線可同時傳輸的數據數就稱爲寬度（width），以比特爲單位，總線寬度愈大，傳輸性能就愈佳。總線的帶寬（即單位時間內能夠傳輸的總數據數）爲：總線帶寬 = 頻率x寬度（Bytes/sec）。

特色:

• 同一組總線在同一時刻只能接受一個發送源,不然會發生衝突
• 信息的發送則可同時發送給一個或多個目的地

分類:

• 傳送分類
  • 串行總線　　二進制各位在一條線上是一位一位傳送的
  • 並行總線　　一次能同時傳送多個二進制位數的總線
• 信息分類
  • 數據總線　　在中央處理器與內存或I/0設備之間傳送數據
  • 地址總線　　用來傳送單元或I/O設備接口信息
  • 控制總線　　負責在中央處理器或內存或外設之間傳送信息
• 對象位置分類
  • 片內總線　　指計算機各芯片內部傳送信息的通道<I^2C總線,SPL總線,SCI總線>
  • 外部總線　　微機和外部設備之間總線用了插件板一級互連<ISA總線,EISA總線,PCI總線>
  • 系統總線　　微機中各插件與系統板<USB總線,IEEE-488總線,RS-485總線,RS-232-C總線>

總線標準依據:　　物理尺寸,引線數組,信號含義,功能和時序,工做頻率,總線協議

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

經常使用名詞

Bit

The bit is a basic unit of information(信息的基本單元) in computing and digital communications. A bit can have only one of two values(只有兩種狀態), and may therefore be physically implemented with a two-state device. These values are most commonly represented as either a 0or1. The term bitis a portmanteau of binary digit.

Byte

字節（英語：Byte），一般用做計算機信息計量單位，不分數據類型。一個字節表明八個比特（英語：Bit）。它也是程序設計語言裏不可缺乏的基本數據類型——整數。

Device driver(驅動程序)

In computing, a device driver (commonly referred to as a driver) is a computer program(電腦程序) that operates or controls(操做或控制) a particular type of device that is attached to a computer. A driver provides a software interface(提供了接口) to hardware devices, enabling operating systems and other computer programs to access hardware functions without needing to know(沒必要知道) precise details of the hardware being used.

JPEG/JPG     GIF     PNG

What is the Difference Between JPG, GIF, PNG, BMP Image Formats?

JPEG/JPG:

JPEG is a commonly used method of lossy compression(有損壓縮) for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss(人眼可覺察到的損失) in image quality.

The term "JPEG" is an acronym(縮寫) for the Joint Photographic Experts Group, which created the standard.

JPEG/JFIF supports a maximum image size of 65,535×65,535 pixels. JPG supports 16.7 million colors and is the preferred format for photographs.

JPG and JPEG stand both for an image format proposed and supported by the Joint Photographic Experts Group. The two terms have the same meaning and are interchangeable.(二者實質同樣，主要是爲了兼容windows以前的版本)

GIF：

The Graphics Interchange Format  is a bitmap image format(位圖格式).

If an image has large areas with flat or single tones colors, then GIF is the format of choice. Think logos, icons, banners, and cartoons which are all preferably GIF images. The GIF format supports 256 colors (i.e. an 8-bit color palette). As they use only 256 colors(顏色少), they make for compact images and consume less bandwidth.

GIF images are compressed using the Lempel–Ziv–Welch (LZW) lossless data compression(無損壓縮) technique to reduce the file size without degrading the visual quality.

支持動圖

PNG:

Portable Network Graphics is a raster graphics file format that supports lossless data compression(無損壓縮). PNG was created as an improved, non-patented replacement(替代) for Graphics Interchange Format (GIF), and is the most used lossless image compression format on the Internet

Like GIF, the PNG format supports 8-bit color but also extends it to 24-bits, thus giving you more color ranges to work with like in a JPEG file. PNG files do not support animation. PNG files are also lossless files retaining color information when they are compressed. Richer images will lead to larger file sizes.

RAM  ROM 

ROM

Read-only memory (ROM只讀內存存儲器) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to store firmware(software that is closely tied to specific hardware and unlikely to need frequent updates) or application software in plug-in cartridges.

RAM(隨機存取存儲器)

Random-access memory (RAM) is a form of computer data storage. A random-access memory device allows data items to be accessed (read or written) in almost the same amount of time irrespective of the physical location of data inside the memory.

What is the difference between ROM and RAM?

There is one major difference between a ROM and a RAM chip. A ROM chip is non-volatile storage and does not require a constant source of power(不須要持續的電源) to retain information stored on it. When power is lost or turned off, a ROM chip will keep the information stored on it. In contrast, a RAM chip is volatile and requires a constant source of power to retain information. When power is lost or turned off, a RAM chip will lose the information stored on it.

Other differences between a ROM and a RAM chip include:

• A ROM chip is used primarily in the start up(啓動階段) process of a computer, whereas a RAM chip is used in the normal operations of a computer after starting up and loading the operating system.
• Writing data to a ROM chip is a slow process, whereas writing data to a RAM chip is a faster process.
• A RAM chip can store multiple gigabytes (GB) of data, up to 16 GB or more per chip. A ROM chip typically stores only several megabytes (MB) of data, up to 4 MB or more per chip.

programming language(編程語言)

A programming language is a formal computer language or constructed language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs to control the behavior of a machine or to express algorithms.

網絡方面

ASCII

ASCII  abbreviated from American Standard Code for Information Interchange, is a character encoding standard (the Internet Assigned Numbers Authority (IANA) prefers the name US-ASCII^[2]). ASCII codes represent text in computers, telecommunications equipment, and other devices. Most modern character-encoding schemes are based on ASCII, although they support many additional characters.

UTF-8

UTF-8 is a character encoding capable of encoding all possible characters, or code points, defined by Unicode and originally designed by Ken Thompson and Rob Pike.

The encoding is variable-length and uses 8-bit code units. It was designed for backward compatibility with ASCII and to avoid the complications of endiannessand byte order marks in the alternative UTF-16 and UTF-32 encodings. The name is derived from: Unicode (or Universal Coded Character Set) TransformationFormat – 8-bit.