system software
System software can be the operating system of a computer or a program which helps other applications to run. System software essentially means a type of "software" which helps the computer "system" to run smoothly and efficiently.
References: http://en.wikipedia.org/wiki/System_software
http://www.webopedia.com/TERM/S/systems_software.html
References: http://en.wikipedia.org/wiki/System_software
http://www.webopedia.com/TERM/S/systems_software.html