计算机信息处理系统或控制系统的部分关键信息往往需要长期或短期保存在存储器RAM 里面。例如汉字终端的通讯规程的选择,用户根据主机的要求选择合适的波特率、传送字节,停止位、校验等等,用户关机或停电息机后重新开机,这些信息都应完好保存。 Some of the key pieces of information in computerized information systems or control systems often require long term or short term storage in the memory RAM. For example, the communication protocol of the Chinese terminal is selected. The user selects the appropriate baud rate, byte transfer, stop bit, verification and so on according to the requirements of the host computer. When the user restarts the computer after powering off or powering off the machine, the information should be kept intact.