# Head crash of a laptop hard drive, does it scratch stuff off the disk? **URL:** \ **Category:** Factual Questions\ **Created:** [February 6, 2018, 6:42am UTC](https://boards.straightdope.com/t/head-crash-of-a-laptop-hard-drive-does-it-scratch-stuff-off-the-disk/808285 "2018-02-06T06:42:24Z")\ **Posts on this page:** 1\ **Page:** 2
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [February 8, 2018, 2:54am UTC](https://boards.straightdope.com/t/head-crash-of-a-laptop-hard-drive-does-it-scratch-stuff-off-the-disk/808285/21 "2018-02-08T02:54:33Z")
> [@wolfpup](#): > > It was all a minimal effort to keep contaminants off the platters but tolerances were much, much lower on those old drives. The heads moved laterally, rather than the radial movement of modern drives, and with considerable force. The big platters and the heads were spring-cushioned as a single unit, and when the heads were seeking you could see the whole assembly bopping around quite violently. For a while, the Univac mainframe hard drives had a defect that rapid head movement between the innermost track and the outermost track at the right timing could cause the entire head comb assembly to break off and literally come flying out through the side of the drive unit. Rather dangerous for any computer operator who might be walking by, especially as this was at approximately crotch height. They had to write code for the disk controller to watch for a pattern of seeks between innermost & outermost tracks, and insert forced seek head quiescence in that. And then modify the code to identify the pattern when the seeks were on different platters f the disk. [Previous page](https://boards.straightdope.com/t/head-crash-of-a-laptop-hard-drive-does-it-scratch-stuff-off-the-disk/808285.md?page=1)