Appendix A Unicode
// 附录A 统一字符编码标准
(unicode /?ju?n??k??d/ n.a character set for all languages 统一字符编码标准. )
Computers use numbers. They store characters by assigning a number for each other. The original coding system was called ASCII (Amnerican Standard code for Inforamtion Interchange) and had 127 numbers (0 to 127) each stored as a 7-bit number. ASCII could satisfactorily handle lowercase and uppercase letters, digits, punctuation characters, and some control characters. An attempt was made to extended the ASCII character set to 8 bits. The new code, which was called Extended ASCII, was never internationally standardized.
To overcome the difficulties inherent in ASCII and Extended ASCII, the Unicode Consortium (a group of multilingual software manufacturers) created a universal encoding system to provide a comprehensive character set called Unicode.
Unicode was originally a 2-byte character set. Unicode version 3, however, is a 4-byte code and is fully compatibles with ASCII and Extended ASCII. The ASCII set, which is now called Basic Latin, is Unicode with the upper 25 bit set to zero. Extended ASCII, which is now called Latin-1, is Unicode with the 24 upper bits set to zero. Figure A .1 shows how the different systems are compatible.
// 计算机使用数字 .他们存储字符通过彼此赋予一个数字. 最开始的编码系统被叫做ASCII(美国标准信息交换代码), 每个被存储的有127位,作为一个数字. ASCII 令人满意地处理大写与小写字母, 数字、标点符号字符。 尝试将ASCII字符扩展为8位。 新的代码，被叫做扩展ASCII, 从来没有被国际标准化。
为了克服在ASCII和扩展ASCII内有的困难，统一字符编码标准联盟（一个关于多种语言软件开发商的组织）创建了一个通用的编码系统，提供了一个可以理解的字符集叫做统一字符编码标准。
统一字符编码标准原先是2个字节的字符集。统一字符编码标准版本3，无论如何，是一个4字节的编码， 并且充分兼容了 ASCII和扩展ASCII。
( assign /?‘sa?n/ vt. If you assign a particular function or value to someone or something, you said they have it. 赋予(某功能或价值) ;
satisfactorily /,s?t?s‘f?kt?r?l? / adv. 令人满意的;
punctuation /p??(k)t??‘e??(?)n/ n. the marks used to divide a piece of writing into sentence, phrases etc. 标点符号，
inherent / ?n‘h??r(?)nt / adj. a qualilty that is inherent in something is a natural part of it and cannot be separated from it. 固有的，内在的，与生俱来的。
consortium /k?n‘s??t??m / n. A consortium is a group people or firms who have agreed to cooperate with each other. 联盟；
multilingual / m?lt?‘l??gw(?)l / adj. multilingual means involving several different languages . 多种语言的；
manufacturer // ,m?nj?‘f?kt?(?)r?(r)/ n. a company that makes large quantities of goods. 制造商、制造公司、制造厂；
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