Storage Devices

  • Created by: unknown42
  • Created on: 29-11-18 13:30

HDDs (Hard Disk Drives) are a form of magnetic storage. They consist of a number of disks made of magnetic material that we call platters. The hard disk drive magnetises and demagnetises billions of tiny individual areas on the platter. Because computers store all data in 1’s or 0’s (known as binary), we can store our data this way as a magnetised area represents a 1 and a demagnetised area represents a 0.


  • HDDs offer a big storage capacity at relatively low cost. You can get a terrabyte (1000 gigabyte) HDD for less than £50.
  • They are also considered a reliable storage method as they have a long life span and tend not to fail outright.


  • HDDs have a relatively slow read/write speed, particularly when compared to their main alternative, the Solid State Drive.
  • They also have a number of moving parts, which means knocks can easily damage the device. This makes it generally a risky option as a portable storage device.
  • They’re also not as portable as other options as they’re heavier and bulkier than many alternatives

SSDs (Solid State Drives) are a form of flash memory storage. They store data using semi-conductor chips. These chips can be switched to either an “on” or “off” state. The “on” state representing a 1 and the “off” state representing a 0. This is storing data in much the same way as your computer’s RAM, except the solid state drive will remember the data even after the computer is turned off.


  • SSDs have very fast read/write speeds, especially compared to hard disk drives. This makes it faster to turn on your computer, load programs and save files.
  • They also consume less power than HDDs. This makes them very useful for devices that often run off of battery power, such as laptops.
  • Because they have no moving parts, they are less likely to be damaged by knocks and bumps, which makes them useful as portable storage devices.


  • SSDs are quite a bit more expensive than HDDs. A 1 terrabyte SSD will cost you over £200 (compared to under £50 for a HDD).
  • Because of this heightened cost, this means that generally SSDs will have a lower storage capacity than HDDs.
  • SSDs have a finite number of writes before they no longer work. This makes them less useful for devices that require regular writing to the disk (like many servers).

USB flash drives use flash storage, much like SSDs, and so they store…


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