Display characteristics
Each field on the screen has a set of display characteristics, called attributes. Attributes tell the 3270 how to display a field, and you need to understand what the possibilities are whether you are using BMS or terminal control commands.
- Field attributes
- These include:
- Protection (whether the operator can modify the field or not)
- Modification (whether the operator did modify the field)
- Display intensity
All 3270s support field attributes; 3270 field attributes explains your choices for them.
Field attributes are stored in the first character position of a field. This byte takes up a position on the screen and not only stores the field attributes, but marks the beginning of the field. The field continues up to the next attributes byte (that is, to the beginning of the next field). If the next field does not start on the same line, the current one wraps from the end of the current line to the beginning of the next line until another field is encountered. A field that has not ended by the last line returns to the first.
- Extended field attributes
- (Typically shortened to extended attributes). These are not present on all models of the 3270. Consequently, you need to be aware of which ones are available when you design your graphical user interface. Extended attributes include special forms of highlighting and outlining, the ability to use multiple symbol sets and provision for double-byte character sets. Table 1 lists the seven extended attributes and the values they can take.