On June 13, 1994, a mathematics professor discovered a bug in Intel’s then-new Pentium CPU. Intel’s new CPU was fast, but it couldn’t divide correctly. The bug became known as the Pentium FDIV bug. It resulted in Intel recalling 60 and 66 MHz Pentium CPUs in stepping levels prior to D1, and 75, 90, and 100 MHz Pentium CPUs in steppings prior to B5. The recall cost Intel $475 million and might have caused reputational damage if more viable competitors had been available at the time. Collectors prize a surviving Pentium CPU with the FDIV bug today.
David Farquhar is a computer security professional, entrepreneur, and author. He has written professionally about computers since 1991, so he was writing about retro computers when they were still new. He has been working in IT professionally since 1994 and has specialized in vulnerability management since 2013. He holds Security+ and CISSP certifications. Today he blogs five times a week, mostly about retro computers and retro gaming covering the time period from 1975 to 2000.
