Processor and memory
The processor is the part of the computer system that handles the instructions used to ensure that hardware and software responds to the user and computer system as expected. Processors can handle millions of instructions per second.
The processor has a clock that sends out signals very rapidly keeping all the instructions it deals with synchronised. The clock speed is measured in hertz (Hz) and is a good indication of how quickly the processor can complete tasks. Most modern processors are measured in GigaHertz (GHz) which means they complete billions of tasks per second.
Computer systems, and in particular processors, are becoming more and more powerful. This chart gives an idea of how processors have improved over the last 35 years. They are able to handle more data at the one time and process it much more quickly.
Modern computers are now so advanced that they have more than one processor, eg dual core 2 processor, quad core 4 processors etc. This means computer systems can work on more than one task at a time.
RAM (Random Access Memory)
This memory stores data whilst the processor is working on it. Once it is finished using it, the memory is erased and new data can be loaded into it.
For example, loading a game on your phone would require loading the instructions into RAM memory. These instructions would be loaded from backing storage and into RAM to allow the processor to work with it. If any changes are made, like saving your progress, these would be saved back into backing storage once the processor has finished working with the file.
If you switch off your computer the contents of the RAM are lost.
ROM (Read Only Memory)
ROM is read only memory, which means that its contents cannot be changed by a user. ROM is needed to allow the system to start up. It holds the instructions that the processor needs to launch the operating system. When the computer is turned on, the contents of ROM are placed in RAM so that the processor can access them and load the rest of the operating system. If you switch off your computer the contents of the ROM are not lost.
