Software flashcards

Topic 4: Software

Is antivirus software application or system software?

System software. It is a utility program, which maintains the computer, rather than an application that does the user's task.

State three functions of an operating system

Any three of: managing files; managing memory; handling interrupts; managing peripherals and drivers; providing a user interface; managing multitasking; providing a platform for applications; providing security; managing user accounts.

How does the processor deal with an interrupt?

It checks for interrupts at the end of each fetch-decode-execute cycle. If an interrupt has higher priority than the current task, it saves the task's state, runs the interrupt service routine, then restores and resumes the task.

Give three reasons for writing in a high-level language

It is machine independent (portable); it is easier to read and debug; the programmer is less likely to make errors; one statement does the work of many machine-code instructions.

Why is assembly language used for device drivers and embedded systems?

It gives direct control of the hardware and memory and can produce code that is fast and uses little memory.

How do a compiler and an interpreter report errors?

A compiler translates the whole program first and gives a report listing all the errors. An interpreter stops at the first error it meets and continues only once it is corrected.

Which translator would you choose to distribute a finished game, and why?

A compiler: it produces an executable file that runs without the translator, runs faster, and does not give customers the source code.

What do auto-completion, auto-correction and prettyprint do in an IDE?

Auto-completion suggests how to finish a keyword or identifier being typed. Auto-correction fixes misspelt keywords. Prettyprint shows keywords and identifiers in different colours and layout so code is easier to read.

How do hardware, firmware and the operating system work together to run an application?

The bootloader (firmware) is run on the hardware at start-up; it loads the operating system, which runs on the firmware; applications are then run on the operating system.

Give the syllabus examples of hardware and software interrupts

Hardware: pressing a key on the keyboard, moving the mouse. Software: division by zero, two processes trying to access the same memory location.