Arithmetic/Logic Unit:
In this unit of the CPU, all mathematical calculations like addition, subtraction, multiplication and division, are done in this unit. Data (subject of the calculations), are momentarily, are transferred to the arithmetic/logic unit (ALU). The operations are performed and the answers to the calculations return to the main storage.
The ALU is also used to make ‘Logical’ comparisons, which will mostly determine the route to be taken throughout the program.
Main Storage:
The main storage of the computer stores all of the data, which is going to be processed. All of the data is entered from an input device. The data will reside in memory while it is being processed, then it will be joined by the results of the processing, which will be contained until it is to be carried out and transferred to an output device.
ROM (read only memory) holds predefined program instructions that were written onto the ROM permanently during the manufacturing. These instructions are ‘non-volatile’, which means the instructions are unaffected by loss of power, from the computer.
RAM (random access memory) is possible to read or write to this type of memory but the contents will be deleted when the power is turned off and the data will not been saved. RAM is also used to hold programs such as Microsoft word while they are running - they are held as files on a disk when they are not in use. RAM also holds graphics data, which is shown on the screen, on the VDU.
The Operating System:
All computers use an operating system. This is a program that controls the whole operations of any program. With out one of these, the computer wouldn’t perform and therefore will not be able to use programs such as Microsoft Word and Microsoft Excel. The operating system controls and handles all input devices such as keyboards, scanners and mouse’s. It also output devices such as the monitor (VDU) and speakers, allows the ability of transferring the data to the numerous disk drives.
A good operating system can control multiprocessors and can even allow the use of operating tasks to open simultaneously. Microsoft® Windows 98 is a popular and well known operating system used mostly in computers in school and businesses and mostly used at home. The more Complex systems are systems such as Microsoft® Windows NT/Windows 2000 and Windows XP; these are mainly used in network environments. If you are using Windows 95 or 98 in a school network server, it is likely that the operating system user is using a system such as Windows XP or Windows 2000.
Applications software
This is a program, which allows the computer to do a specific job. Examples are Microsoft Word, Microsoft Access, paintbrush, desktop publisher, adobe acrobat etc. These are used to do different jobs such as:
Microsoft Word
This program is used to create actual words or text on the computer. It includes tools, which allow data to be manipulated easily and are used to check for accuracy in spelling and grammar, by using processes such as spelling and grammar checks.
Configuration
A system will be setup on a standard configuration for most users.