Topics / Hardware / SSD Vs HDD


Although both secondary storage, there are major differences between how Solid State Drives (SSDs) and Hard Disk Drives (HDDs) work.

It is these differences that create the advantages and disadvantages of each storage device.

How do HDDs and SSDs work?

How does a HDD work?

  • HDDs use magnetism to store/represent binary
  • It is mechanical with moving parts (a spinning disk platter and swinging actuator arm)
  • Data is saved within tracks and sectors on the disk surface, and read/written from the tip of the actuator arm
  • It can take time to reach the data, especially if it is fragmented (files split into different areas of the disk)

How does a SSD work?

  • SSDs have no moving parts
  • Data is saved using integrated circuits and NAND flash memory
  • Data can be accessed at virtually equal speeds from anywhere on the disk (very handy for fragmented files)

Advantages and disadvantages of SSDs and HDDs

Advantages of HDDs

  • Cheaper per unit of storage
  • Huge capacities available and affordable
  • No limit to write cycles

Disadvantages of HDDs

  • Not as robust (e.g. might break if dropped)
  • Not as fast
  • Takes time to get to full speed

Advantages of SSDs

  • More robust
  • Faster, especially for fragmented data
  • Uses less power
  • Generates less heat
  • Lighter
  • Often a smaller form factor
  • Quieter

Disadvantages of SSDs

  • More expensive per unit of storage
  • Limited number of write cycles

Exam style questions about SSDs and HDDs

Watch the video below for some examples about how to answer questions on this topic.

Topics / Hardware / SSD Vs HDD

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