北大方正为什么盗窃火星人ZMODEM协议通信产品？

           中央巡视组进驻北京大学之际，需要把当年北大方正集团盗窃火星人ZMODEM协议产品的真实动机搞清楚，说明白。

ZMODEM is a file transfer protocol developed by Chuck Forsberg in 1986, in a project funded by Telenet in order to improve file transfers on their X.25 network. In addition to dramatically improved performance compared to older protocols, ZMODEM also offered restartable transfers, auto-start by the sender, an expanded 32-bit CRC（循环冗余校验）, and control character quoting（引用）, allowing it to be used on networks that might "eat"（吃掉） control characters. ZMODEM became extremely popular on bulletin board systems (BBS) in the early 1990s, displacing earlier protocols such as XMODEM and YMODEM.

The key improvement in ZMODEM was the introduction of sliding window support for improved performance.   

Generally file transfer protocols break down a file into a series of packets, and then send them one-at-a-time to the receiver. If the packet is received correctly an ACK message is sent and the sender then starts sending the next packet.

实际情况是，当年方正远程传版业务遇到的问题就是我国当时通信线路质量很差，远程数据经常出现中断，急需改进。方正集团职工袁庭球“踩点”盗窃火星人ZMODEM协议产品的动机昭然若揭，不用多说。

说明：袁庭球是北航计算机系计算机通信专业硕士生毕业，自然懂得ZMODEM协议产品对方正业务的价值。

袁萌  3月21日