ubuntu环境下字符设备驱动程序的示例。使用方法是：终端中make生成设备目标文件。insmod globalvar.ko 载入设备。mknod /dev/globalvar c 2548 0 生成设备文件，c表示字符设备，2548是主设备号。编译执行test测试驱动程序。-ubuntu environment, character device driver for example. To use is: make the terminal device generates the target file. insmod globalvar.ko loading equipment. mknod/dev/globalvar c 2548 0 generating device file, c, said character device, 2548 is the major device number. Compile the implementation of test test driver.