Or while formatting a floppy disk!

That was huge.

People today don't realize how much time was spent formatting floppy disks, and how slow the process could be. So slow that eventually companies started selling pre-formatted disks and charging extra for them.

OS/2 could give you back hours of productivity each month simply because you could do something else while formatting a disk.

The problem was Windows handling of interrupts. Until, i think, Win2k, generating a lot of interrupts (floppy, parallel port, high network activity) will slow Windows to a crawl.