Share this post

What’s inside a hard drive?

A hard drive is the storage centre of your PC or laptop, but have you ever wondered what’s actually inside a hard drive or how they work?

Well here’s your chance to learn a little about the storage system inside your computer…. 

whats in a hard drive

Want this on your website?

Just copy and paste the code below into your site:

<a href=””>
<img src=””/>


Internal to ex

Share this post


Add yours
  1. Scott's Bro 26 January, 2015 at 12:38

    Really interesting article Scott, you should become more than an infrequent blogger!

    I’ve always wondered how my Hard Drive stores my 3 editions of Black Beauty, I have to take my external hardriver EVERYWHERE I trot.

  2. Schrodinger's Cat 27 January, 2015 at 18:01

    Nice job, but one correction. It is now well accepted that the brain does not store information in a single location (like a hard drive platter), but memories are diffuse. If the entire brain was a hard drive, it would need serious defragmentation. Hence the analogy at the beginning (“if your computer was a brain…”) is incorrect, although the reverse would be true (“if your brain was a computer…”), but that would not be as illustrative as intended.

  3. Ivan 3 February, 2015 at 22:22


    Thanks for the great article and fantastic photos. It explained things from the simple level to far more in details – Interesting to know about tracks, blocks and sectors on hdd platters.

    One thing I notices was where you mentioned common rpm as being 3,600 or 7,200…
    I believe the most common slower speed is 5,400 rpm.. 3,600 would be painfully flow.


  4. Steve 21 May, 2015 at 11:56

    Slight correction – you mention Seek Time being the time between a data request and fulfilling that request. It isn’t. Seek time is one component of this delay between request & fulfilment. From a hard disk perspective there are 2 elements – Seek Time and Latency. Seek time is the time it takes the actuator to position the heads over the correct track where the data is; Latency is the time it takes the disk to rotate and bring the start of the sector under the head so that it can start to read. The overall time from a request for data to fulfilment has more components, such as reading the index (what used to be called a VTOC – Volume Table of Content) the part of the disk which holds the index of where everything is on the disk – this is a set position normally closest to where the heads are at rest to speed up access. So a data request reads the ‘index’ to find where the data it needs physically lives on the disk – then the heads reposition to find the start of it. Simples! One other item to add, is that on multi-platter disks there is an area known as a ‘cylinder’ which is all of the tracks positioned below one another – so data from all of these can all be read without repositioning the heads.

  5. Steve 2 21 May, 2015 at 12:19

    Well said Steve 1 (or “Too true, Blue” as you appear to be same vintage as me !) One other minor inaccuracy – “Winchesters” refers not to the platters but to the actuator technology. Originally all drives used stepper motors which were big and cumbersome, but the development of the voice coil actuated “Winchester” version so named simply because the arms move in an arc like the cocking action of a Winchester rifle enabled development of ever smaller drive footprints like we see today.

  6. Steve 3 5 August, 2015 at 12:03

    As you can see, my fellow counterparts love Google. The article isn’t a comprehensive analysis of the hard drive, it’s just a simple explanation designed to give people the general idea. It’s a pity there’s too many Steve’s who like to one-up after getting their request & fulfillment from Google.

  7. Steve 25 January, 2016 at 11:11

    Steve3 – you appear to be a bit of a to$$er my friend! Not really a great contribution to the discussion you’ve made is it – what’s the point of anything you’ve said??? If you’d bother to read the whole article and the comments after (which was obviously too much trouble for you) you’d see that neither myself nor Steve 2 need to refer to Google. No one’s one-upping (except you!). The article – which is good – isn’t “a simple explanation” it goes into some technical depth – clusters, tracks etc. – (true, there are also cartoon pictures so numpties like you may be attracted in the first place) but there are some factual inaccuracies and correcting them in the polite and helpful way that has been done would be seen as a good thing by any sensible person. Shame you felt your irrelevant and incorrect diatribe was worth sharing with anyone.

  8. Steve 4 25 January, 2016 at 13:22

    In fact the name “Winchester” derives from the IBM 3340 disk which had 30Mb of fixed storage and 30Mb of removable storage, it’s namesake being the Winchester .30-30 rifle.

  9. Patricia 25 January, 2016 at 15:39

    Really good article, even for us geriatric numpties. Much appreciated. Keep up the good work.

  10. Not Steve 14 March, 2016 at 11:09

    I think there may be 1 too many Steve’s in this kitchen. Just remember folks, Opinion’s are like ar$eH0les. Everybody has one.

  11. Chris 14 March, 2016 at 11:18

    The largest currently available 3.5″ mechanical (non-SSD) hard drive is 10TB, not 20.. if you had searched your own site you would see that

  12. Dave Jennings 20 October, 2016 at 11:06

    This article is exceptional in teaching the non tech people a little bit of what is going on in a hard drive, let’s have more articles like this.We can all say ” are but”

Post a new comment