as ( - table summarizes the featuresadvantagesand disadvantages of relative file organization table relative file organization features advantages disadvantages provides an effective way to access individual records the record number represents the location of the record relative to the beginning of the file records in relative file are of fixed length relative files can be used for both random as well as sequential access every location in the table either stores record or is marked as free ease of processing if the relative record number of the record that has to be accessed is knownthen the record can be accessed instantaneously random access of records makes access to relative files fast allows deletions and updations in the same file provides random as well as sequential access of records with low overhead new records can be easily added in the free locations based on the relative record number of the record to be inserted well suited for interactive applications use of relative files is restricted to disk devices records can be of fixed length only for random access of recordsthe relative record number must be known in advance indexed sequential file organization indexed sequential file organization stores data for fast retrieval the records in an indexed sequential file are of fixed length and every record is uniquely identified by key field we maintain table known as the index table which stores the record number and the address of all the records that is for every filewe have an index table this type of file organization is called as indexed sequential file organization because physically the records may be stored anywherebut the index table stores the address of those records the ith entry in the index table points to the ith record of the file initiallywhen the file is createdeach entry in the index table contains null when the ith record of the file is writtenfree space is obtained from the free space manager and its address is stored in the ith location of the index table record address of nowif one has to read the th recordthen there is no number the record record need to access the first three records address of the th record can be obtained from the index table and the record record can be straightaway read from the specified address ( record in our exampleconceptuallythe index sequential file organization can be visualized as shown in fig record null an indexed sequential file uses the concept of both sequential as well as relative files while the index table is null read sequentially to find the address of the desired recorda null direct access is made to the address of the specified record null in order to access it randomly null indexed sequential files perform well in situations where figure indexed sequential file organization sequential access as well as random access is made to