Briefly define the following terms and give two examples of each $($use recognised sources $$ use the correct APA referencing style when defining these terms as well as when referencing in the bibliography$).$

$2\mathrm{.}1$ System development methodology.

$2\mathrm{.}2$ IS$/$IT architecture.

$2\mathrm{.}3$ Operating system.

$2\mathrm{.}4$ Database management system.

$2\mathrm{.}5$ System software.