data field is an elementary unit that stores single fact data field is usually characterized by its type and size for examplestudent' name is data field that stores the name of students this field is of type character and its size can be set to maximum of or characters depending on the requirement record is collection of related data fields which is seen as single unit from the application point of view for examplethe student' record may contain data fields such as nameaddressphone numberroll numbermarks obtainedand so on file is collection of related records for exampleif there are students in classthen there are records all these related records are stored in file similarlywe can have file of all the employees working in an organizationa file of all the customers of companya file of all the suppliersso on and so forth directory stores information of related files directory organizes information so that users can find it easily for exampleconsider fig that shows how multiple related files are stored in student directoy student' personal info file student' academic info file student' fees info file roll_no name address phone no roll_no name course marks grade in sports roll_no name fees lab dues hostel dues library dues figure student directory file attributes every file in computer system is stored in directory each file has list of attributes associated with it that gives the operating system and the application software information about the file and how it is intended to be used software program which needs to access file looks up the directory entry to discern the attributes of that file for exampleif user attempts to write to file that has been marked as read-only filethen the program prints an appropriate message to notify the user that he is trying to write to file that is meant only for reading similarlythere is an attribute called hidden when you execute the dir command in dosthen the files whose hidden attribute is set will not be displayed these attributes are explained in this section file name it is string of characters that stores the name of file file naming conventions vary from one operating system to the other file position it is pointer that points to the position at which the next read/write operation will be performed file structure it indicates whether the file is text file or binary file in the text filethe numbers (integer or floating pointare stored as string of characters binary fileon the other handstores numbers in the same way as they are represented in the main memory