Defrag98 is a browser recreation of the Windows 98 Disk Defragmenter, the utility that somehow turned a boring maintenance chore into compelling viewing. Colored blocks shuffling around a grid, a progress bar crawling toward 100%, and the vague sense that your PC was busy doing something important. This is that, running in a browser tab.
Note (2026): I’ve since rebuilt Defrag98 from scratch for a more faithful simulation. If the technical side interests you, read Rebuilding Defrag98: Getting the Details Right. What follows is the original 2024 announcement.
I built the first version with React , Tailwind CSS , and Next.js. The look was the easy part. The part I actually cared about was the motion: the real defragmenter didn’t march through clusters in order, so I wrote a custom algorithm that picks clusters to process in a way that feels closer to the original: a little chaotic, gradually settling into order.
It found a far bigger audience than I expected. It reached the front page of Hacker News, got a write-up in The Verge, and went live on Product Hunt. Thanks to everyone who tried it out and shared it around, and if you’ve got a minute, an upvote on Product Hunt never hurts.
What the Windows 98 Disk Defrag Simulator does
- Windows 98 UI : the blue-and-gray interface, recreated down to the window chrome.
- Multiple drive options : pick from virtual drives of different sizes and speeds, each defragmenting at its own pace.
- Hard disk sounds : the clicks and whirs of a late-90s drive, if you want them on.
- Pause and resume : you control when it runs, just like the original.
- Custom defrag algorithm : the cluster shuffle is simulated, not scripted, so no two runs look quite the same.
The frontend is React on Next.js, styled with Tailwind CSS. The interesting bit is that defrag algorithm: instead of animating a fixed sequence, it randomizes which clusters get processed and when, which is what keeps a run from looking canned. The settings screen lets you trade drive size against speed, so you can set up anything from a crawling old disk to a quicker late-90s one.
Why I built it
I grew up watching this screen. For anyone who did, it’s a quick hit of nostalgia. For anyone who didn’t, it’s a small window into what keeping a PC running felt like in the 90s. No real disks are harmed and nothing actually gets optimized, and that’s the whole point.
Keeping it online
Keeping this online isn’t free: there’s a domain and hosting to cover. If you’ve enjoyed reliving this classic Windows experience, a small donation helps keep it running for everyone else. Every bit is appreciated.
Defrag98 is free. If it makes you smile, share it. I’d love to see your reactions with #Defrag98.
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