在文件中保存目录内容，创建文件或子目录可以用命令行命令：MD、CD、RD、MK（创建文件）、DEL（删除文件）和DIR。目录项包括文件或目录名称、类型（文件、目录或空目录项）、创建日期以及下一个目录项指针、下一级目录项指针。-Saved in a file directory contents, create a file or subdirectory can use command-line commands: MD, CD, RD, MK (create file), DEL (delete files), and DIR. Directory entry includes the file or directory name, type (file, directory, or an empty directory entries), creation date and the next pointer to a directory entry, the next one directory entry pointer.