Today we are used to the fact that computers can undertake a huge number of tasks. They use their processing ability to do a host of tasks from calculating numbers through to running programmes that cover everything from office tasks like word processing to accounting and very much more.
The way in which all computers work is very similar. They have the same basic functional units within them and these provide the same basic oeprational features.
Although computers take many different forms, everything fromt he huge mainframe computer used for processing enormous amounts of data to laptop computers and even the computers embedded in other electronic devices, looking at how these computers work, it can be seen that they all follow the same principles.
The main elements within a computer or embedded processing engine include:
- Processor / CPU: The processor or more correctly the central processing unit is the circuit block where the logical processing is undertaken within the computer. It allows addition subtraction and other functions to be undertaken.
- Read only memory, ROM: The ROM is typically used for the storage of a programme inside the computer. In larger computers it is used for the storage of the boot programme, but in embedded processors and computing systems it is sued for the storage of all the programme. Unlike RAM, a ROM is a permanent form of storage that does not lose its content when the power is removed. Some forms of ROM are re-programmable and the programme data can be updated when the correct conditions are set. This form of ROM is called a programmable read only memory or PROM.
- Random access memory, RAM: The RAM elements of the computer or processor are used for temporary storage of programme data or instructions. The data can be written to the RAM at any time, and an important feature of the processor RAM is that it loses its date when the power is removed. RAM comes in two forms - static and dynamic.
- Dynamic RAM: Dynamic RAM is used within a computer or processor of any form is the primary form of RAM used and is used to store the majority of the data. It is more dense than static RAM, but is slower than static RAM.
- Static RAM: This form of RAM is used with some processors, especially within computers for cache memory - memory that is used for frequently access data. It is faster than dynamic RAM but less dense.
- Interface: The interface or I/O which stands for Input / Output is the way in which the overall computer interacts with the outside world.
- Data bus: The data bus is the data bus, consisting of several lines that is used to pass data long. The data bus is typically used to send complete bytes of data at a time, i.e. bit parallel and byte serial. As such systems require the number of lines equal to the number of bytes in each byte. Thus typically data bus widths may be 4, 8, 16, 32 64 bits wide dependent upon the system.
The processor hardware for the computer can take many physical forms. It may be a large mainframe coputer used for huge amounts of processing, it can be a desktop computer, it can be a small microcontroller based system set up for a specific task where only a small amount or processing is required. Whatever the requirements, the computer processor will have the same basic structure and the same basic circuit blocks.