Yes, it is exactly what it sounds like. I’ve seen it linked a few times and it is charming in that retro way I like, so I’m linking to it, too.
Windows 98 Disk Defrag Simulator
I’m not saying I wish I had to defrag disks again, mind you. This just recalls a simpler time and, perhaps, one where you were more directly in control with what happened on your home computer1Speaking of nostalgia, I remember when people consciously drew a distinction between a work computer and a home computer.