Back then, program trading, computer robotic dealers caused an avalanche of selling that blew up the markets in a catastrophic vicious circle of robottrading.
Then some hedge fund may start off their new tradingrobot designed to do clever things across markets, but whoops, off flies a few tens of millions of dollars in the wrong direction.
The robot takes the huge order, has a look at the order book, looks at the recent flow of trading, does some math and starts slipping bits of the order out into the market in digestible pieces.