We don't like to bother you with too much technical material but a minimum of knowledge should help you not only to deeper understand what's going on in the computer but also to know at which product properties you have to look when buying a new one.
The processor builds the unthinkably fast heart of each computer. In the modern PCs, this heart pulses with already more than 800 million times in a second. The proper technical way to express it is by saying 800 MHz (megahertz).
The above mentioned tact frequency of a processor means that so many computations per second are done. All that a computer brain really does is calculating numbers.
The computer memory is realized as one or more chips. You can think of it as a very long chain of points. Each of these points can memorize only either a one or a zero value. These are the only things about which a computer ever "knows". But using only ones and zeros, it is possible to represent all numbers and to do computations with them. This way of numeric representation is called binary or dual system.
The smallest unit of the computer memory is called bit. Every bit can have the value of either 1 or 0 and nothing else. The bits are the points on the chain in our imagination.
The standard memory unit is a byte. One byte contains 8 bits and can therefore represent exactly 256 values.
The most modern PCs have 128 or 256 MB (megabyte) of RAM. RAM is the shorthand for Random Access Memory which means that the processor can set or read each memory position directly.
The computer memory implemented in the chips (RAM) is a temporary one. It is used by the processor for loading the data of running programs and documents. But every time when you shut down the computer, all contents of RAM are lost.
To store data permanently - not only for one computer session but also between the sessions - the hard disks are used. The hard disk is a fixed, non-removable storage medium installed in a hard disk drive. The actual interior noise level of a computer is composed of the ventilator cooler noise and the one made by fast and shambling rotation of the hard disk in its drive.
Nowadays hard disks have the capacity of 20 GB (gigabyte = billion bytes). You can, however, put more than one hard disk into your computer tower.
Besides the hard disks there are also floppy disks as external storage medium available. Floppy disks or diskettes have a very low memory capacity of 1.44 MB. Because of ascendant worldwide networking and its small capacity, floppy loses its importance from day to day.
The data transfer between the processor, RAM, the hard disks, the floppy disks etc. is organized through so-called bus connection. The bus is a very fast electric conductor.
In addition to all on-board hardware devices, each computer also provides a possibility to connect external devices. The connection slots you find in most cases on the back side of the computer tower. We call them "ports". I list here the most important kinds of ports:
Today, most PCs are also connected to the world wide net - Internet.