A: Application programs like Web browser /Banking system /Airline reservation, these programs are purchased or written by the users to solve their particular problems, such as word processing, spreadsheets, engineering calculations, or storing information in a database.
Q: Who can write application program? or How much training I need to make me capable to write a application program?
A: Any one who accept a little computer technology training can do it without understanding to the deep knowledge/concept of computer science. And the people who are only capable to write application program (not too big and complex) is called software developer.
The definition of application program also define a fact that there will be infinite nubers of application programs. From an old programer's advice, a wisdom is gaven - How you write these program, which programming language you use to write them, they are all doesn't matter. What does matter is the reason why you write these program, and what you's gonna do with these programs.
Programs runnig modes: kernel mode, supervisor mode, user mode.
A: Whose job is to manage all these devices and provide user programs with a simpler interface to the hardware.
Q: (Function) What operating system do?
A: (a).Extending the machine by extends the computer’s instruction set. (b).Managing resources (provide for an orderly and controlled allocation of the processors, memories, and I/O devices among the various programs competing for them.) Resource management includes multiplexing (sharing) resources in two way: in time and space
Q: Why operating system existed? What is the benifit of operating system?
operating systeminstead. (b).Operating system make programmer won't need to involved with detials that need write program to keep track all these components and use them correctly everytime they write a software.
Mainframe Operating Systems
Server Operating Systems
Multiprocessor Operating Systems
Personal Computer Operating Systems
Real-Time Operating Systems
Hard Real-Time System- If the action absolutely must occur at a certain moment (or within a certain range), we have a hard real-time system. For an example the system in car manufacturing factory.
Soft Real-Time System- If missing an occasional deadline is acceptable. Like Digital audio or multimedia system.
Embedded Operating Systems
Smart Card Operating Systems
Process- A process is basically a program in excution.