ISO/ANSI standard user labels (UHL and UTL)

The ISO/ANSI standard user labels (UHL and UTL) is 80 bytes in length and is used to identify additional information about the data set. All information in the user labels is user data. The user labels directly follow the header/trailer group and can be up to any number of user labels per data set.

Table 1. Format of the ISO/ANSI Standard User Labels (UHL and UTL)
Offset	Data type	Length	Contents
0	Character	3	Label identifier
3	Character	1	Label number
4	Character	76	User data

The program describes the contents and function of each of the following fields.

Label identifier
The characters identify the type of data set label.
UHL

User Header Label (the beginning of a data set)

UTL

User Trailer Label (the end of a data set)
Label number
The relative position of this label within the set of labels of the same type; there is a no limit of user labels per data set.
User Data
This field specifies any user information in the user label. The system ignores the information in this set but passes it to a specified user label program.