From the following list choose all the tasks an operating system performs.

manages files
manages memory
powers up
works as an intermediary between the hardware and the software
stores files
runs tests
manages which program gets access to memory and for how long

Manage memories - Operating system has utilities that could help users to manage their memories. Such utilities include Disk Maintenance and Disk Degfragmentation which are helpful to detect problems within your disk storage. Works as an intermediary between the hardware and the software - OS has a special program called kernel. Basically, a kernel can recognize a command in relation to hardware. For example, when the user click on Ctrl and P keys on the keyboard, the kernel would send alert to the corresponding hardware which is the printer then do the task. Manages which program gets access to memory and for how long - OS manages tasks. It supports multi tasking which means several processes can happen at a time. In order to do that, OS manage the computation and priorities of tasks to ensure that the user can have a good experience.