Software and Operating System Basics
Software and operating-system questions test how system and application software differ, what an OS manages, and how processes and files are handled.
System software versus application software
System software manages the machine; application software performs user tasks. The operating system (OS) is core system software that manages processes, memory, files, devices and security. Utilities such as disk cleanup, antivirus and backup support maintenance; language translators (compiler, interpreter, assembler) convert code; device drivers let the OS talk to hardware.
OS functions and process states
An OS provides a user interface (GUI or CLI), multitasking, memory allocation, file-system management and access control. A process moves through new → ready → running → waiting → ready → terminated. The scheduler chooses a ready process; an interrupt or I/O request moves a running process to waiting. Virtual memory uses secondary storage to extend apparent RAM, but excessive paging slows the system.
Worked example
A student opens a browser while a music player is already running. The OS keeps both processes in memory, gives each a time slice, and switches on a timer interrupt. When the browser requests a web page, its process enters waiting for network I/O; the scheduler runs the music player from ready. The browser returns to ready when data arrives. No process is running on a single-core CPU at the same instant.
Traps that cost marks
- Calling an OS an application; an OS is system software.
- Confusing multitasking with multiprocessing; one CPU can interleave processes but not execute two at once.
- Saying formatting deletes hardware faults; formatting prepares storage logically.
- Mixing compiler (whole program, object code) with interpreter (line-by-line execution).