1. OPERATING SYSTEM BY KINSHUK RASTOGI

2. WHAT IS AN OPERATING SYSTEM? What is an operating system in the first place? An operating system is a software that connects the user to the saved items in the hardware. For example if I open a laptop and I press the on button then the os will boot up and ask for the password to operate the machine. Any machine usually needs an operating system to work.

3. FEATURES OF OS 1. Program Execution. Handling Input /Output Operations. Manipulation Of File. Error Detection And Handling. Resource Allocation. Information And Resource Protection. The different types of os are multi user and multi tasking, real time, single user multi tasking, embedded, and distributed.

4. MAC OS X This operating system is made by apple Inc. this system was made and released by Steve jobs. It was in the market in 2009. The mac system has features like maps, notifications, multiple displays, finder tabs, and tags.

5. WINDOWS Windows is a series of graphical interface operating systems developed, marketed, and sold by Microsoft. Microsoft Windows came to dominate the world's personal computer market with over 90% market share, overtaking Mac OS, which had been introduced in 1984. This program is user friendly and can be used by anyone. You can do a lot of multitasking in windows.

6. UNIX more than one user can use the machine at a time supported via terminals (serial or network connection) multi-tasking more than one program can be run at a time hierarchical directory structure to support the organization and maintenance of files portability only the kernel ( <10%) written in assembler tools for program development a wide range of support tools (debuggers, compilers.

7. LUNIX multitasking: several programs running at the same time. multiuser: several users on the same machine at the same time (and no two-user licenses!). multiplatform: runs on many different CPUs, not just Intel. multiprocessor: SMP support is available on the Intel and SPARC platforms (with work currently in progress on other platforms), and Linux is used in several loosely-coupled MP applications, including Beowulf systems (see http://cesdis.gsfc.nasa.gov/linux- web/beowulf/beowulf.html) and the Fujitsu AP1000+ SPARC-based supercomputer.http://cesdis.gsfc.nasa.gov/linux- web/beowulf/beowulf.html multithreading: has native kernel support for multiple independent threads of control within a single process memory space. runs in protected mode on the 386. has memory protection between processes, so that one program can't bring the whole system down.

8. MY CHOICE According to me I think that the best os is windows because it is user friendly and is also very easy to use.