What is the difference between information system and management information system?

Often, they are used interchangeably. Basically, think of an Information System (IS)as that system that is used by and accessable to everyone. Any factory worker may use an Information System to look up a part, or you may use an Information System in the library to find a book. The Management Information System, or MIS, is that system that is used by management to make management decisions. So the factory worker may not have access to the MIS, but the CEO would use the MIS to schedule work flow, hire more employees, make decisions about building new factories. The librarian in your local library would use the IS to find a book but an MIS to schedule other librarians to work on peak traffic days.