chapter 5 - system software Flashcards
operating system
a system software used to control hardware and provide an environment on which programs can be run
command line interface (CLI)
users enter text and commands
graphical user interface (GUI)
uses colour, pointers, windows, icons and menus
menu-driven interface
uses menus and further menus to allow users to communicate with hardware
process
the execution of a program
utility program
a program that might be provided by the OS or installed as a separate entity. relatively small and only one purpose e.g. to analyse, maintain, configure, optimise or repair a system
hard-disk defragmenter
rearrange blocks for each file to ensure files are stored contiguously in memory, for faster reading and reduced head movements
library programs
pre-written modules that can be linked into a program without amendment to perform common or complex tasks. they are extensively tested
dynamic link library (DLL)
a shared library file which is only loaded into main memory when required at run-time and can be made available to several programs at once. self-contained programs that are already compiled
high-level language
resembles natural english language and syntax. one line = many CPU instructions. easy to understand but takes more time for CPU to execute
low-level language
direct CPU access, but harder to write and understand
machine code
binry 0s and 1s. directly executable, rarely used by humans as it is impossible to translate and understand
intepreter
translates high-level language into machine code one line at a time
compiler
translates high-level language into machine code all at once
java virtual machine (JVM)
interface between OS and program. each machine has its own JVM based on hardware and byte codes
