How Computers Work
Computer systems have a CPU (central processing unit) at their core. This preforms all the calculations, operations and tasks that need to be done while someone uses the computer. The speed of the CPU is normally measured in Gigahertz. Companies that make CPUs include Intel and AMD. In general, the higher the speed, the faster the computer system will run.
Another measure that affects computer performance is the amount of RAM (random access memory). This stores data that is currently in use - the more memory you have the more programs you can have open at any one time. A modern desktop PC will probably have about 1-8 Gigabytes of RAM. Memory that loses its data when the power is removed is know as volatile memory.
For permanent storage of data, most computers still have a hard disk drive or HDD. These work by magnetically storing binary code onto a metal disk. A modern computer will probably have a HDD that can store between 500MB and 1TB of data. There are 1024 GB in a TB.