{"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":214,"pdf_page":230,"physical_index":230,"physical_index_base":0,"printed_page_status":"recognized","page_sha256":"431de34c492fa34f27fbf10cfe05fcd4371d1163c4b3a9ff84418948021fca86"},"chapter":"编码隐匿在计算机软硬件背后的语言","content":"下面这幅是控制面板与64K×8良AM阵列的逻辑结构框图。\n\n当控制端开关闭合时，通过操作16个地址开关，可以选择65,536个地址中的任何-个，灯泡的状态将表示该地址中所保存的8位数据。我们可以使用8个数据开关表示出一个新数，然后把写操作端置1，从而将数据写入存储器。\n\n64K×8的RAM阵列和控制面板这一组合的确很实用，它可以帮助我们存储65,536个8位数据并且读取其中的任意一个。与此同时，我们也给其他部件提供了接入系统的机会-——需要接入系统的通常是-些电路部件-这些部件可以轻易地读取并利用存储器中存放的数据，还可以把数据写入存储器。\n\n关于存储器有一个问题尤其值得我们注意，而且需要特别注意。在学习第11章的时候，我们曾介绍过逻辑门的概念及原理，但是没有画出组成逻辑门的单个继电器的结构图。特别是，当时没有指明每个继电器都与某个电源连接在起。只要继电器连通，申流就会流过电磁线圈并产生磁场，继而吸下金属片。\n\n-个辛辛苦苦装满65,536字节珍贵数据的64K×8RAM阵列，如果断掉电源，会发生什么事情呢？首先所有的电磁铁都将因为没有电流而失去磁性，随着“梆”的一声，金属片将弹回原位，所有继电器将还原到未触发状态。RAM中存储的数据呢？它们将如风中残烛般消失在黑暗中。\n\n正因为如此，随机访问存储器也被称为易失性（volatile）存储器。为了保证存储的数据不丢失，易失性存储器需要恒定的电流。\n\n编码——隱匿在计算机软硬件背后的语言\n\n214","previous_page":213,"next_page":null}