This was an early instance of holistic system performance work. Automated Pit Trading was a world first. Instead of chaps in blazers waving at eachother and throwing orders on the floor (to be collected by sweepers), APT provided a SunView GUI to traders across London. Fairness was guaranteed by providing everyone with exactly the same hardware platform. The customer was not at all happy when we introduced the SPARCstation 1+, because it meant everyone had to be upgraded. RAM was always at a premium, and I had been asked to go in to pare down the kernel and system services to a minimum. While I was there, I was asked to investigate an application hang. It turned out that the printer (which was not spooled) had run out of paper, and that the application was blocking on a write to the printer port!