File spanning is a process used in computer data storage in which a single large file is broken up into smaller ones. This can be used for a number of different reasons, though it is commonly applied to data backup and storage, since a larger file can be repaired from the smaller ones. File spanning is also frequently used for data transfers, as the small files can be sent more easily and then reassembled into the large one after the transfer is complete. Some programs can use this process in a way that goes unseen by a computer user, although other software gives the user control over it.
The basic idea behind file spanning is for the data in one large file to be broken up across the "span" of numerous small ones. This can be used quite effectively for data backup, since multiple small files on a system can easily represent a larger one. If there is an issue with the larger file, such as data corruption or loss, then the smaller ones can be accessed for repair. This allows a computer system to more easily find data needed to recover or repair a system, as file spanning allows discrete sections of data to be stored separately.
File spanning can be an ideal method for handling data transfers for large pieces of information. A single, large file may take hours to send across a network or download over the Internet. During this transfer time, an error or loss of signal could result in the entire file becoming corrupted and the transfer would need to be started over from the beginning. File spanning allows multiple smaller pieces of data to be sent and then assembled into the larger file afterward. If one of these files becomes corrupted, it is easy to retransfer it and then use it properly in the reassembly.
There are some computer programs that use file spanning without the computer user even realizing it. Data archiving software, for example, can employ this system "behind the scenes," while only presenting the archived file to the user. Some pieces of powerful software include utilities and tools that give the user control over the file sizes created through file spanning. This lets someone more easily archive data in a way that is effective for his or her particular needs. Someone storing information on numerous pieces of physical media can then span data over an appropriate number of files for transfer onto the "hard copy" backup.