Md Y Hassan

DOS Disk operating system (DOS) was the first widely used operating system for personal computers. DOS allows the user to navigate, open and otherwise manipulate files on their computer from a command line instead of a GUI like Windows. How DOS Works? • DOS uses a command line, or text based interface, that allows the user to type commands. By typing simple instructions such as cd (change directory) or pwd (print working directory), the user can browse the files on the hard drive, open files and run programs. • While the commands are simple to type, the user must know the basic commands in order to use DOS effectively, almost similar to UNIX. • The first version of windows, through Windows 95 ran on top of the DOS operating system. This is why many DOS related file types are still used by windows.

Kernel • The kernel is the central module of an operating system. It is the part of the operating system that loads first, and it remains in the main memory. Because it stays in the memory, it is important for the kernel to be as small as possible while still providing all the essential services required by other parts of the operating system and applications. Kernel has complete control over everything that occurs in the system.