Conventions for class names

Many of the GOFF records require specifying a class name. Some of these names can be chosen freely (for example, for user-supplied information), and other names must follow some rules. Class names reserved to IBM® are called "Reserved Names", and class names that can be used freely are called Non-Reserved Names. (Note that class names are not external symbols!)

Class names appearing in object modules are case sensitive.
Reserved class names are a maximum of 16 characters and are of the following form:
```
>>-letter--underscore--identifier------------------------------><
```
- The first character of a reserved class name is a letter (A-Z).
- The second character of a reserved class name is an underscore character (_).
- The remaining 1 to 14 characters of a reserved class name form a normal alphanumeric identifier: a letter followed by either letters, digits or both.
The following reserved class name prefixes are currently in use:
- Class names starting with B_ are reserved for the binder.
- Loadable class names using the prefix C_ are reserved for translators creating Language Environment-enabled code.
- X_,Y_,Z_ as well as non-loadable C_ classes are reserved for general translator use.
All other letter_ class names are reserved for future use.

The following classes can be specified by language translators and other creators of GOFF records:

B_ESD          External Symbol Dictionary Class
B_TEXT         Text Class
B_RLD          Relocation Directory Class
B_SYM          Internal Symbol Table Class
B_IDRL         Language-Translator Identification Data Class
B_PRV          Pseudo-Register Class
B_IDRU         User-specified Identification Data Class

OBJ inputs to the program management binder will be automatically mapped to these classes.

The following classes are reserved for internal use by the program management binder, and cannot be specified on GOFF records:

B_IDRB         Program Management Binder-created
               Identification Data Class
B_IDRZ         SuperZAP-created Identification Data Class
B_MAP          Internal Program Object Mapping-Data Class
B_LIT          Loader Information Table
B_IMPEXP       Import-Export Table

It is expected that conventions will be established for the use of other classes. IBM translators should use class names of the form:
```
C_xxxxxxxxx    Translator-defined Classes
```
Non-Reserved class names follow the normal formation rules for external symbols except they are limited to 16 characters in length.