Rewrite the following sentence in simple English.
The collection of computer programs that are used to operate a computer system.
A set of software used to run a computer.
Complete the following task based on the instruction and optional input provided.### Instruction:
Rewrite the following sentence in simple English.

### Input:
The collection of computer programs that are used to operate a computer system.

### Output:
A set of software used to run a computer.