故障1:计算机启动后向A驱动器插入软盘,用DIR命令能正常显示目录内容,用COPY命令能将A盘上的内容拷贝到C盘中,用DEBUG命令也能读A盘文件。在A驱动器中换一张磁盘,用DIR命令显示目录内容时,所显示的仍然为上一张磁盘内容,用COPY命令由A盘向C盘拷贝某一已知文件名的文件时,屏幕显示XXXXFilenot found。用RESTORE命令由 Fault 1: After the computer starts to insert a floppy disk drive A, with the DIR command to display the contents of the directory, use the COPY command can copy the contents of the A disk to C drive, DEBUG command can also read the A disk file. A drive to change a disk, use the DIR command to display the contents of the directory, the display is still the previous disk contents, use the COPY command from the A disk to the C drive to copy a file of a known file name, the screen display XXXXFilenot found. RESTORE command by