My first presentation was on a paper I wrote (solving large Linear Algebra problem on the Cray XM-P v. the Cray-2 ). 2/3rds of the way thru the talk the director of a rival supercomputer center said, “That’s impossible, a Cray XM-P/24 cannot beat a Cray-2 on that class of problems”. I was too dumbfounded to respond before the packed session. Luckily for me a mathematician (German woman) stood up and said, “It’s possible because I/O is 2nd Order and computation is 3rd order.”
The was the first and last nightmare experience I had. I enjoy giving technical presentations.

