# Cylindrical Prism icon on Laptop? **URL:** \ **Category:** Factual Questions\ **Created:** [April 25, 2010, 3:50am UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274 "2010-04-25T03:50:03Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![HeWhoLikesThee](https://avatars.discourse-cdn.com/v4/letter/h/958977/32.png) [@HeWhoLikesThee](https://boards.straightdope.com/u/HeWhoLikesThee)\ **Post date:** [April 25, 2010, 3:50am UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274/1 "2010-04-25T03:50:03Z")
Hey, On my laptop, there’s this icon that looks like a cylindrical prism. Its right beside the power LED, and has it’s own LED too. What is it suppose to indicate? ---
**Author:** ![Mines\_Mystique](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@Mines\_Mystique](https://boards.straightdope.com/u/Mines_Mystique)\ **Post date:** [April 25, 2010, 3:52am UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274/2 "2010-04-25T03:52:16Z")
Does the LED flash a lot, especially when you are saving or opening a large document? It is most likely the indicator for hard drive activity. ---
**Author:** ![HeWhoLikesThee](https://avatars.discourse-cdn.com/v4/letter/h/958977/32.png) [@HeWhoLikesThee](https://boards.straightdope.com/u/HeWhoLikesThee)\ **Post date:** [April 25, 2010, 3:56am UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274/3 "2010-04-25T03:56:33Z")
Oh yeah it does. Thanks! ---
**Author:** ![Nanoda](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Nanoda](https://boards.straightdope.com/u/Nanoda)\ **Post date:** [April 26, 2010, 3:57pm UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274/4 "2010-04-26T15:57:25Z")
In computing, storage is indicated by a cylinder shape. You’ll also see this if you use any GUI tools for databases. I would _guess_ that it comes from hard disks. A drive is almost always a stack of platters, each divided in to circular tracks. There is then (or at least, used to be) a concept of a [cylinder](http://en.wikipedia.org/wiki/Cylinder_(disk_drive)), which incorporates a certain track from all platters, thus making a cylinder. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [April 26, 2010, 4:10pm UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274/5 "2010-04-26T16:10:18Z")
> [@Nanoda](#): > > I would _guess_ that it comes from hard disks. As I understand it, [it](http://en.wikipedia.org/wiki/Hard_disk_drive#Icons) goes back to [the days when hard disk drives were the size of washing machines](http://en.wikipedia.org/wiki/File:DysanRemovableDiskPack.agr.jpg). ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [April 27, 2010, 5:16pm UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274/6 "2010-04-27T17:16:48Z")
> [@KneadToKnow](#): > > As I understand it, [it](http://en.wikipedia.org/wiki/Hard_disk_drive#Icons) goes back to [the days when hard disk drives were the size of washing machines](http://en.wikipedia.org/wiki/File:DysanRemovableDiskPack.agr.jpg). Whoa! 200Mb! That could almost hold the file I’m working on right now. Almost. 😃 I actually remember using those damn monstrosities into the eighties. Damn I’m old. ☹ ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [April 27, 2010, 6:20pm UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274/7 "2010-04-27T18:20:09Z")
> [@Si\_Amigo](#): > > Whoa! 200Mb! That could almost hold the file I’m working on right now. Almost. 😃 I actually remember using those damn monstrosities into the eighties. Damn I’m old. ☹ > **[The Hard Disk You've Been Waiting For](https://gizmodo.com/the-hard-disk-youve-been-waiting-for-5524908)** > > Looking for hard disk? Oh, buddy boy, have I got a deal for you. You want MBs? I've got 10 fat ones right here. Five, if you're not a heavy user. And $3400 for 10 MB. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [April 27, 2010, 6:35pm UTC](https://boards.straightdope.com/t/cylindrical-prism-icon-on-laptop/537274/8 "2010-04-27T18:35:56Z")
> [@Munch](#): > > [The Hard Disk You've Been Waiting For](http://gizmodo.com/5524908/the-hard-disk-youve-been-waiting-for) > > $3400 for 10 MB. Wow, it’s even got read lookahead! _What a bargain!_