American Notes COMPUTERS

As Yogi Berra might say, it was deja vu all over again. Five weeks after a computer-science graduate student forced the Defense Department to shut down , its Arpanet computer network by infecting it with a self-duplicating electronic virus, the Pentagon learned that one of its smaller military information systems, Milnet, had been broken into by an unknown hacker. Last week Mitre Corp., a Massachusetts-based defense contractor, warned the Pentagon that someone had gained unauthorized access to Mitre's system, which is linked to the Arpanet network. Fortunately, the invader had access only to nonclassified material, and none of it was damaged. Nevertheless, the Defense Department severed Milnet's connection to Arpanet until software experts could come up with a fix.