What is the difference between serial and sequential files? How searching is applied on both?   

Ans: A serial file is one where the records have been stored in the order where they have occurred. They have not been sorted into any specific order.

An instance of a serial file is an unsorted transaction file.

A shopping list is an instance of a non-computerised serial file. Items are appended to the list while that item runs low.

Serial files can be stored on tape, disc or in memory.

A sequential file is one where the records are stored in sorted order of one or more key fields.

An instance of a sequential file is a sorted transaction file.

A class register is an instance of a non-computerised sequential file sorted on surname