The Christmas Tree Worm begins to affect IBM mainframe computers around the world. The worm was delivered by e-mail and drew a Christmas tree text graphic on the user’s monitor and searched out other network users to e-mail. Named CHRISTMA EXEC because IBM systems only supported eight-character filenames, it was the world’s first widely disruptive computer worm. While the worm was not intentionally destructive, the volume of e-mails it created could disrupt a user’s work and began to overload e-mail systems. It reached IBM’s VNet e-mail network on December 15th and two days later had crippled it to the point they had to shut it down to eradicate the worm.