A serial file is a type of file that contains information, which is recorded in the file in the order it occurred. It can also contain files, in which case the files information would be listed in the order they were saved in the serial file. The information or files are essentially recorded in chronological order. New information is appended, or recorded, at the end of the serial file only. There are also no subsets or directories of information in the file.
Serial files are usually stored in the computer's internal memory, but they could be stored on a disk as well. When a computer reads a serial file, it starts at the beginning and reads the information sequentially. When a computer is at a high usage level, a serial file can be beneficial due to the speed and ease at which a computer can read it.