A file sequence is a series of related computer files that contain some data indicating their inclusion in a common set. The data that marks a file as part of a file sequence can be stored in the name of the file or can be contained in a data field inside of the file. The physical location of the file can also be used to signify the presence of a sequence. The sequence can be used to help organize files on a system visually, or it can be used to facilitate input into a program designed to process the series of files. Some software programs are able to treat a file sequence as a single object to allow random access to areas buried deep within the object without the need to open a single large file.
A sequence of files can be indicated by adding an ascending series of numbers or letters to the file’s name before the final extension separator. Most operating systems will organize these files by name when displayed, although there are certain technical aspects that can cause a list to appear out of order. Specifically, file names are listed in strict alphanumeric order on most operating systems, with no translation of numbers into actual integers. This means that numbers with fewer digits than their greater counterparts, such as 1 and 10, need to have 0s padded before the lower number to match the number of digits for correct sequencing.
In some instances, it can be advantageous to have not only the names of files be in sequence but also to have the actual data physically recorded in a long, unbroken chain on the media. This can have the benefit of very fast file access as well as enabling the use of certain software optimizations to further increase performance. The process of maneuvering files to be physically contiguous is known as file descattering. The descattering process can be coupled with a defragmentation process to help create a more efficient and less wasteful file system.
When the files that make up a file sequence are spaced at many random physical points on a medium, they are considered to be scattered. File scattering can occur as a natural process of the computer architecture or software. As each file is written, the operating system will attempt to find some available space, but this space does not need to be sequential. In fact, the parts of a single file can be scattered over several areas. This can affect the file access speed and can complicate data backup procedures.
A file sequence is an integral part of the functioning of many programs that handle large amounts of data. They are often used in financial applications and can be used for automatically generated files in real-time systems or digital cameras. Multimedia files or composite data files also use file sequences to assemble a large single file from many separate sources, some of which could have been created independently of each other.