1. A file is a collection of related records used to store and retrieve data for various applications like payroll, inventory, customers, vendors, etc. 2. The main operations on files are adding, changing, and deleting records. To add a record, the new record is entered through a terminal and updated to the hard disk. To change a record, the existing record is retrieved from the hard disk, updated on the terminal, and written back to the hard disk. To delete a record, the record is logically removed by marking it as deleted on the hard disk.