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Top 10 List of Week 00

1. Operating System
   Operating system is software that manage a computer’s hardware. It also provide a basis for application programs and acts as an intermediary between the computer user and the computer hardware.
   

2. A Network Operating System
   A network operating system is an operating system that provides features such as file sharing across the network, along with a communication scheme that allows different processes on different computers to exchange messages.
   

3. A File
   A file is a collection of related information defined by its creator. Commonly, files represent programs (both source and object forms) and data. Data files may be numeric, alphabetic, alphanumeric, or binary. Files may be freeform (for example : text files) or may be formatted rigidly (for example : fixed fields such as an mp3 music file).
   

4. Virtual Memory
   Virtual memory is a technique that allows the execution of a process that is not completely in memory. The main advantage of this scheme is that it enables users to run programs that are larger than actual physical memory.
   

5. Parallelization
   Parallelization is a technique that divides a program into separate components that run in parallel on individual cores in a computer or computers in a cluster.
   

6. Interrupts
   Interrupts are used throught modern operating system to handle asynchronous events. Device controllers and hardware faults raise interrupts. To enable the most urgent work to be done first, modern computers use a system of interrupt priorities. Because interrupts are used so heavily for time-sensitive processing, efficient interrupt handling is required for good systems performance.
   

7. Virtual Machine Manager or Hypervisor
   

   Type 0 hypervisors : implemented in the hardware and require modifications to the operating system to ensure proper operation.
   Type 1 hypervisors : provide the environment and features needed to create, run, and manage guest virtual machine.
   Type 2 hypervisors : simply applications that run on other operating systems, which do not know that virtualization is taking place.
   

8. Multi Programming
   A computer running more than one program at a time. For example : program A runs for some time and then goes to waiting state, in the mean time program B begins its execution. So the CPU does not waste its resources and gives program B an opportunity to run.
   

9. Multiprocessing
   Multiprocessing is the use of two or more CPUs (processors) within a single Computer system. Multiprocessing refers to the hardware (i.e., the CPU units) rather than the software (i.e., running processes). If the underlying hardware provides more than one processor then that is multiprocessing. It is the ability of the system to leverage multiple processors’ computing power.
   The difference between multiprocessing and multi programming is : Multiprocessing is basically executing multiple processes at the same time on multiple processors, whereas multi programming is keeping several programs in main memory and executing them concurrently using a single CPU only.
   

10. Multitasking
    Multitasking refers to having multiple programs, processes, tasks, threads running at the same time. This term is used in modern operating systems when multiple tasks share a common processing resource (e.g., CPU and Memory).