Application Programs Application programs are the top software layer. You can perform specific tasks with these programs, such as using a word processor for writing, a spreadsheet for accounting, or a computer-aided design program for drawing. The other two layers, device drivers and the operating system, play important support roles. Your system might run one application program at a time, or it might run many simultaneously. Device Drivers Device drivers are a set of highly specialized programs.
Device drivers help application programs and the operating system do their tasks.
They interact directly with computer hardware elements and shield the application programs from the hardware specifics of computers. System An operating system is a collection of programs that controls the running of programs and organizes the resources of a computer system. These resources are the hardware components of the system, such as keyboards, printers, monitors, and disk drives. Your AIX operating system comes with programs, called commands or utilities , that maintain your files, send and receive messages, provide miscellaneous information about your system, and so on. An application program relies on the operating system to perform many detailed tasks associated with the internal workings of the computer.