-23:59:59

The largest bill for computer time that I ever received was for a negative amount.

In 1967, the Stanford Computer Center installed an IBM System 360/67 mainframe. Because government contracts required that services charged to sponsored research projects be at the lowest rate charged to anybody, student research assistants had accounts billed at the same rate (although the department or the center paid the bill).

I seem to have been the first user to have a job running at the stroke of midnight. When I got my statement that month, I had a rather large balance in my favor. It turned out that the accounting routine used the time-of-day clock, and subtracted the time when the job started from the time when it ended. The resulting credit ran to five figures.

I thought that this was hilarious, but Jane was spooked by it: Never mind that little minus sign, she just didn't feel comfortable with a bill for an amount larger than our combined annual incomes.

This is one piece of paper I really wish I had saved. It would now be framed and hanging on my wall.