BOF is a specific marker that shows where a file starts. It supports the use of specific operators in computer programming that need to be oriented to that point at the beginning of the file for them to work properly.

Consider a basic text analysis tool applied to a text file. The developer or programmer might construct a simple loop that starts with BOF and proceeds incrementally through each character until it reaches the end of the file, such as:

From BOF
Read x
X = x + 1
Do until EOF
Common problems with these types of markers also reveal the level of fault tolerance in programming syntax. For example, if these tags aren't used, or are used improperly, the program can run the loop and come back with various error messages specifying that a certain position was not found. Using simple syntax like BOF/EOF, developers communicate directly with computers to make programs that work and to identify bugs or errors that could cause programs to hang or crash.