> PC Speaker driver. Probably no one ever used this, but making the PC speaker play proper digital audio was something fun. DOSBox even emulates this quite well! This code was also responsible for the single worst bug I had during the entire IT development. When I was writing this driver, I mismatched the PUSHes and POPs in the interrupt handler; which then had a bad interaction with Microsoft's SmartDrive disk cache. The net result of this was SmartDrive trashed my hard drive and I lost over a week of work on IT and university assignments.

What a horrible and funny bug. Reminds me of Linus attempting to write AT commands to his modem, but redirecting them to the wrong /dev file and accidentally replacing the boot record of his disk drive with a Hayes command.