I may be mistaken, but I believe what was involved in the 1987 crash was simple automated computer trading...the decline levels exceeded the parameters of the programs, and since they had no floors or stops included they just kept selling and fed into the downward spiral.
High-frequency trading that effectively games the exchanges is a comparatively recent phenomenon, within the last few years.
I understand. I was referring to autonomous computers for trading in general. I remember a year or two ago Goldman went after some Russian national who had designed and patented one of their systems. It incorporated multiple telephone switches. The guy ran off with the schematics and copies of the software. They caught him and he was indicted. But the story gave a glimpse of how these systems could issue then cancel orders in a millisecond.