Tape Mark (End-of-file)
Tape Data Recovery - Tape Mark (End-of-file)
In computing, tape mark refers to a special character or coding or a piece of reflective material or other devices attached to the physical end of a magnetic tape. Tape mark denotes the end of the file, after which no data can be read from the tape without rewinding it.
Tape mark is also known as end-of-tape and is commonly abbreviated as EOT. It is usually indicated by two tape marks, one at the beginning and the other at the end.
Typically, the tape mark consists of a gap of approximately 3.5 inches of tape, which was followed by a single byte that contains the character 13 (hexa) for nine track tapes and 17 (octal) for seven track tapes.
The nine track tapes had reflective stickers placed at the 14′ end to signal the end of tape (EOT) to the hardware. This method of signaling EOT with space remaining to write trailer blocks allowed support for multivolume labeled tapes. The reflective strip that is used to denote the impending physical end of the tape is known as EOT markers.
EOT was the standard used in many older generations of computers including IBM 360.
End-of-file (EOF) is a condition similar to EOT occurring in computer operating system when no more data can be read from the data source such as a file or a stream. In such situation, the file access or other I/O functions return a value equal to the symbolic value of EOF to indicate that end-of-file condition has reached. .
