An OS is the interface between the user and hardware , it controls the execution of software instructions and controls the operation of other computer components.
1.Stand Alone OS : These files are stored on the hard disk and loaded into the computers RAM when the system boots. These control the interface and working of a single computer. Ex : Windows OS, MAC OS.
2.Network Operating System (NOS): These are used to co-ordinate and control a group of computers connected together in a LAN. Ex: Windows xp, windows 2000, Unix, Linux.
3. Embedded Operating System : These are used in handheld devices like a PDA. These are called embedded because they are completely stored inside the ROM.( Read Only Memory.) Ex: Windows CE, Palm OS.
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