THE OPERATING SYSTEM (Informaticinfo)

THE OPERATING SYSTEM

The physical composition of the computer and its different components are called the "hardware" (the material).

The set of programs which are recorded in the computer are called the "software".

If the motherboard and the processsor are the masterpieces of the hardware of a computer, the operating system (OS) is the masterpiece of the software. For a computer to operate various tasks have to be performed in permanence in the background. These tasks can be related with handling RAM, inputs/outputs (i.e. reading and writing) to the mass storage devices, allocating memory on the swap file when needed, distribution of the working time of the processor between several programs running at the same time, etc. Let's say a program has to wait for a few thousandths of second to read a file on a hard disk. These few thousandths of second will be allocated to another program which would be the next one in the priorities. That could be a calculation program and god knows how many calculations can be done within one thousandth of a second! Then when the first program has gotten its informations and is ready to carry on, as soon as the 2d program has completed a number of his calculations the priority is gotten back to the first program, and so forth.

All that requires a complex management. That management is taken care of by an amount of programs at a lower level, closer to the machine than the usual programs. That set of programs is what one calls the operating system. Where is it recorded? On your hard drive. These are all the "system files" that you are advised not to touch to unless you know what you are doing.

There are various types of OS: Windows (95, 98, etc, and XP) is certainly the best known and the most marketed. Unix and its variants such as Linux, Solaris, Mac OS, etc are undoubtedly more flexible for knowledgeable users but still less user friendly than Windows for Mister Everybody. Yet they are much cheaper, some like Linux are even entirely free of charge... One of the reasons why they are more flexible is that any knowledgeable person can have access to and change anything they like, which is not the case with Windows.

That operating system uses drivers to handle peripherals. A driver is a particular software which allows the handling of all functions of a peripheral (hard disk, printer, CD-ROM drive, etc). Thus a higher level program (closer to human language) can simply say "Let's store that stuff in the hard disk". Well it will use a more esoteric synthax which will mean exactly that. And the operating system will transfer that instruction to the driver of the disk which will devide this into a series of precise instructions and electrical impulses resulting in motions of the arm of the hard disk with a rigorous precision and a perfect timing so that finally the right bits will be recorded at the exact spots of the disk where they had to be written even though that one is spinning at several 1,000s rpm. It's high tech.

When there is a problem with a peripheral it can come from a problem with its driver.