System software is the software that starts, controls and shuts down the computer hardware and makes it function. The system software make available the computer hardware environment to the programmers or to the maintenance personnel.
System software is of two types Operating system software and utilities software. Unix, Linux, MS Windows are operating system softwares. Anti virus software, task manager, network monitoring tool (control panel), back up software etc. are utilities softwares. Further compute language developers use compilers and interpreter softwares to run their programs like C, C++ or Java. These softwares are also system softwares. The user programs in these computer languages are application programs/software.
The system softwares help the system administrators to control the computer, monitor the use of computer by the user, and also repair/maintain the computer hardware and system software.
In contrast, the application software is the software package that an end user uses for his purpose. They are like Word - a text editor, a game, web browser like firefox, google chrome etc.
The language and utilities associated with the system software may be GUI based or command based. They are special purpose and usually written specific to a type of hardware. They are to be rewritten or recompiled for other computer hardware platforms.