1 Stress echocardiogram: This is an echocardiogram that is performed while the person exercises on a treadmill or stationary bicycle. 2  This test can be used to visualize the motion of the heart's walls and pumping action when the heart is stressed.
Viruses require an active host program to cause damage and infect other executable files or documents, while worms are stand-alone malicious programs that can self-replicate and propagate via computer networks, without human help.
Taking 15 minutes to spread worldwide, the SQL Slammer worm was one of the largest and fastest spreading worms ever. For this reason, some have described Slammer as the first Warhol worm (had its 15 minutes of fame), a fast-propagating Internet worm hypothesized in 2002 in a paper by Nicholas Weaver.