Stoll commented that although Morris may not have intentionally designed the virus to be destructive, he did take deliberate measures to make sure that the virus would be difficult to defeat--and that he would not be caught.

"Some people are calling this just a harmless experiment that went wrong. I'm not so sure," said Stoll. "If it were meant to be harmless, then why did [Morris] put in all these defenses? There are still some things that bother me about this."

The first, and most simple, of Morris' defenses, was that he released the virus at midnight, giving it a head start on the systems managers across the country who were home asleep when the virus began to spread.

When the system managers, did arrive, they found that the virus program was written in a secret code so that they were not able to understand it. The process of decoding the program took hours of valuable time.

After they had finally decoded the virus and began trying to interpret the program, it became apparent that Morris had included fake instruction sequences--portions of the program which would never be executed--to lead them on wild goose chases in their attempts to understand the operation of the program.

Beginning last Thursday afternoon, system managers turned off each machine, and reprogrammed them by hand to eradicate the virus. By Friday, most of the machines at Harvard and around the country had been put back on line. THE INCUBATION OF A VIRUS

EARLY THURSDAY MORNING 12:00 A.M.  VIRUS RELEASED BY ROBERT MORRIS, JR. 2.00 A.M.  MORRIS CALLS HARVARD TO WARN OF INFECTION LATE THRUSDAY MORNING  PROGRAMMERS BEGIN DEBUGGING SYSTEMS AFFECTED BY VIRUS LATE FRIDAY  MOST UNITS WORKING AGAIN, MORRIS NAMED AS VIRUS ORIGINATOR