OS

1. Process manager

1.1. keeps track of the status of each process

2. File manager

2.1. checks every type of file that is on the system

2.1.1. data files

2.1.2. program files

2.1.3. compilers

2.1.4. installed applications

2.2. sets permission so certain user can see certain files

3. Network manager

3.1. provide users to share hardware and software resources

4. Memory manager

4.1. In charge of the main memory

4.1.1. Scans every requests from memory space

4.1.1.1. checks if it's valid

4.2. allow allocation of memory spaces that are not taken up already

5. Device manager

5.1. monitors every device channel and control unit

5.2. has to choose the most efficient way to allocate all of the system devices that connected to pc