{"resolved":true,"match_type":"uuid","source_type":"original_book","book_id":"38270854-596f-4a26-8183-db8c968c6020","title":"编码 隐匿在计算机软硬件背后的语言","author":null,"edition":null,"publisher":null,"year":null,"isbn":"9787121181184","requested_by":"printed_page","book":{"source_type":"original_book","book_id":"38270854-596f-4a26-8183-db8c968c6020","id":"38270854-596f-4a26-8183-db8c968c6020","uuid":"38270854-596f-4a26-8183-db8c968c6020","title":"编码 隐匿在计算机软硬件背后的语言","normalized_title":"编码隐匿在计算机软硬件背后的语言","author":null,"edition":null,"publisher":null,"year":null,"isbn":"9787121181184","isbns":["9787121181184","0123456789","6044921875","3039331000","0000000000","0000000000000"],"parsed":true,"ai_readable":true,"document_type":"book","page_count":438,"navigation_url":"https://workshop.closeclaw.top/ai/book/38270854-596f-4a26-8183-db8c968c6020","title_url":"https://workshop.closeclaw.top/ai/title/%E7%BC%96%E7%A0%81%20%E9%9A%90%E5%8C%BF%E5%9C%A8%E8%AE%A1%E7%AE%97%E6%9C%BA%E8%BD%AF%E7%A1%AC%E4%BB%B6%E8%83%8C%E5%90%8E%E7%9A%84%E8%AF%AD%E8%A8%80","fixed_page_url_template":"https://workshop.closeclaw.top/ai/book/38270854-596f-4a26-8183-db8c968c6020/page/{printed_page}","path_api_url_template":"https://workshop.closeclaw.top/api/ai/book/38270854-596f-4a26-8183-db8c968c6020/page/{printed_page}","read_url":"https://workshop.closeclaw.top/api/ai/read/38270854-596f-4a26-8183-db8c968c6020","page_url":"https://workshop.closeclaw.top/api/ai/books/38270854-596f-4a26-8183-db8c968c6020/page","search_url":"https://workshop.closeclaw.top/api/ai/books/38270854-596f-4a26-8183-db8c968c6020/search"},"page":{"printed_page":317,"pdf_page":333,"physical_index":333,"physical_index_base":0,"printed_page_status":"recognized","page_sha256":"8fdc3f928e1ab2b54cebd8d23692c2ccd7968e900fe16785dda471cc21e9b0fd"},"chapter":"编码隐匿在计算机软硬件背后的语言","content":"前面讲到的 95个编码也被称为图形文字（graphic characters)，因为它们可以被显示出来。其实 ASCI码还包含 33 个控制字符（control characters)，它们用来执行某一特定功能，因而不用显示出来。为了完整地讨论ASCI编码，下面将这33个控制字符也列举了出来，有一些的确很难理解，不过不用在意。其实在ASCI码公布以后，当时人们更多的是想把它用在电传打字机上，所以，如今其中的许多编码已经渐渐离开了人们的视线。\n\n人们最初的想法是可以在图形字符中使用控制字符，以便对文本格式进行基本的调整。举个例子或许会帮助你更好地理解这种做法：假如有一台电传打字机或者打印机，它负责解析ASCⅡ码，解析之后做出相应的操作，最后在纸上打印出字符。设备的打印头每打印一个字符就向右移动一格，通过这种方式来对ASCII码做出响应。而要实现这些操作就需要用到控制字符。\n\n举个例子来讲，看看下面这个十六进制字符串：\n\n41 09 42 09 43 09\n\n编码09代表水平制表符，简写为Tab。假设打印的过程中，所有水平排列字符的起始位置都为0，Tab的作用是在下一个水平位置即在距前一个字符的间距为字符长度8倍的位置打印下一个字符，如下所示：\n\n这种简单有效方法使得字符可以保持按列对齐。\n\n有一些控制字符甚至沿用至今，例如换页符（12h)，它使得打印机跳出当前页，并\n\n20 ASCII 码和字符转换\n\n317","previous_page":316,"next_page":318}