postmark是个压力测试磁盘的工具，netapp公司开发。可以模拟邮件服务器的负载。-postmark is a tool for stress testing the disk, netapp developed. Can simulate the load on the mail server.

在89c51 型 系统上 运用tlc2543芯片 模拟数字电压 实现功能(In 89C51 type system, the TLC2543 chip is used to simulate the digital voltage to realize the function)