If by computer systems you mean operating systems, then:
1) Windows
2) Macintosh
3) Linux
MAC, WINDOWS, LINUX/UNIX
No, the Apple computer is a personal computer. The 2 main operating systems sold today are Microsoft Windows 8 and Apple OSx Mountain Lion.
Computers.
The answers are:Metric system and English system
There are four basic and main database management systems that are used today. Those four include hierarchical, network, relational and object-oriented.
The democracy, oligarchy, monarchy, and dictatorship, are the four main governing systems of the present day:-) hope this helps..
The computer is used for research and fun.
To arrange data in a particular manner.these manner or set of rules is defined in the data structure so that the data used in computer systems can properly used at necessary time.
The main use of a computer is to be fed data, process that data and come up with information which can be used to make decisions, but in today's culture, they are also being used as a source of entertainment.
CC Cleaner
2 many
Yes, it is!
On some computer Operating Systems the way the computer identified who was using the computer used a file called userdata.ini