3/19/2016 Creeper and Reaperby Bob Thomas, BBN Colleague
Among the things I admired most about Ray were his playfulness, his willingness to take on a challenge, and the speed with which he could solve complex problems. The recollection below describes a fun interaction Ray and I had more than forty years ago. In the early 70's when the ARPA network was young I worked with Ray at BBN. During that period I began experimenting with techniques for enabling a program running on one host computer in the network to move itself to another host computer in the network in a way that enabled it to continue working on its application on the new host computer without loss of the program state, data, etc. needed to perform the application. At that time there were about seven or eight PDP-10 host computers running an operating system called TENEX in the ARPA network. In those days Ray was, among other things, one of the TENEX developers and maintainers. To do the experimentation I wrote a small program whose job was to maintain a simple database which it updated periodically. It was also programmed to move itself and its database from its current TENEX host computer to another randomly chosen TENEX host computer in the network. The program itself was named Creeper since it crept around the network doing its simple task. Just before Creeper left one host computer to move on to another it output the message "I'm the Creeper; Catch me if you can" on the operator's console of its current host computer. Although I often ate lunch with Ray at work and occasionally car pooled with him I hadn't mentioned anything about Creeper to him. A day or so after the Creeper program started on is journey around the ARPA network Ray started getting calls from the various TENEX sites asking what this Creeper thing was and what they should do to get rid of it. That got Ray's attention. It took Ray remarkably little time to analyze the situation. Within a day he wrote and launched a program which he named Reaper to seek out and destroy Creeper. To do this Reaper used the ARPA network to periodically visit each TENEX host in the network and look for Creeper. Wherever Reaper found an instance of Creeper Reaper would kill it. Comments are closed.
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