软件保护中，把不能复制的标记或签名存放在软盘上的方法，用一个特殊测试程序来检测签名是否存在，如不存在，则被保护的程序不能运行。

In software protection, a method of giving a mark, or signature, that cannot be duplicated, to a floppy disk. A special test routine detects if a signature is present, and if it is not found the protected program will be disabled.