How Computers Work!

CPUs-RAM-HDDs-What is it all about?


CPU stands for Central Processing Unit. This is the most important component of the computer and it acts as the 'brain' of the device. The CPU is responsible for carrying out calculations, operations and tasks that are being done.

Companies that make CPUs are intel and AMD.

The CPU is measured in Gigahertz (Ghz) and this is a clock speed, meaning it is how many cycles are done per second. For example, if your CPU had 2Ghz it does 2 billion cycles per second.


The RAM (Random Access Memory) of the computer stores the data that you are currently using on your computer. This means that if the computer is turned off, unless the work is saved, the work your on will be lost. This type of work is called volatile (is lost when not saved).

RAM is measured in Gigabytes, most modern desktop PCs will have 1-2Gb of RAM. The more memory you have, the more things you can have open without you computer slowing down.

Maufacturers of RAM include:

  • Patriot
  • G-skill
  • Mushkin


The Hard Disk Drive (HDD) is the main, and usually the largest, data storage hardware device of a computer. This is the permanent storage of data, and it works by magnetically storing binary code onto a metal disc. The operating system, software titles and most other files are stored in the HDD.

Hardware= the physical components of a computer such as the mouse, keyboard, system unit (graphic cards, sound cards).

Operating system= The low-level software that supports the basic functions of a computer, such as scheduling tasks.

The storage of a HDD is measured in terabytes (TB) or Megabytes (Mb). A modern computer will usually have a HDD which can store between 1TB to 500Mb.

There are 1024 gigabytes in 1 tearbyte.

The speed of the HDD is measured in RPM (Revolutions per minute).

Manufacturers of HDDs include:

  • Seagate Technology
  • Toshiba
  • Western Digital

Inside your computer - Bettina Bair