Eduqas A-Level Computer Science functional programming and the operating system overview quiz quiz

always prints its result to the screen before it returns the value to the caller

depends only on its inputs and has no side effects

changes global variables each time it is called, updating shared state outside itself

uses iterative loops instead of recursion to repeat any work it has to do

a function is able to see and read every global variable defined in the program

functions must be written in Haskell or another purely functional programming language

a function call can be replaced by its result without changing behaviour

data held in a structure can be changed in place rather than copied to a new value

for loops

while loops

goto statements

recursion

a new list of the same length with each element transformed

a single combined value formed by folding all the elements together

a shorter list holding only the elements that pass a given test

the original list left completely unchanged, with no new list created

runs faster than ordinary functions because the compiler gives it a higher priority

takes a function as an argument or returns a function

can only be called once in a program before it must be redefined again

never returns a value of any kind back to the code that called it

Process management and CPU scheduling

Memory management

Editing a user's photographs

Managing input/output and the file system

always running whichever process currently has the highest priority assigned to it

running processes strictly in their order of arrival and never interrupting any of them

running the shortest job first, choosing the process with the smallest burst time

giving each process a fixed time slice in turn

saves its state (registers and program counter) onto a stack

shuts down the whole machine and powers the system off completely

deletes the currently running process and removes it from memory entirely

ignores the interrupt altogether and simply carries on with the next instruction

variable-size logical segments matching the program's structure

equal fixed-size blocks (frames and pages)

a single contiguous block allocated to each separate process

encrypted regions that only the operating system kernel can read

adding more physical RAM chips to the motherboard to enlarge main memory

compressing the operating system in memory so that more programs can fit in RAM

using secondary storage as if it were extra main memory, swapping pages

deleting unused programs from disk to free up space whenever memory runs low

A web browser application

A spreadsheet package

A video game program

An operating system

software written specifically for one organisation's unique requirements

general-purpose off-the-shelf software sold to many different users at once

free software distributed with its source code open for anyone to modify

a type of utility program bundled with the operating system to maintain it