APPENDIX D IMPLEMENTATION-DEPENDENT FEATURES

The following introduces, but does not exhaustively list those matters left to the implementors.

  1. The control functions which will be selected for implementation.
  2. The number of bits, number of characters, and form of the bit combination or bit combinations generated by a single or multiple key depression.
  3. Whether characters entered become immediately visible or are processed (partially or fully) prior to becoming visible.
  4. If there is a buffer, whether it has a capacity larger than, identical to, or smaller than, the display area.
  5. Whether a control function occupies buffer space, display space or both.
  6. At what point(s) in the processing of the data stream control functions are to be executed.
  7. What the representation of an erased state may be.
  8. Whether certain control sequences remain in their encoded state or are transformed into data in special registers and tables.
  9. Whether or not there are implementation-defined values for parametric functions when the Standard does not specify a standardized default value.
  10. What action will be taken in error recovery.
  11. The initial state of a device upon power-up, including the settings of the modes.
  12. Whether the width of a displayed character position is fixed or variable (depending on the character occupying the position).
  13. The action to be taken by a device if a control function or a graphic character is received which the device cannot implement, because of design limitation or temporary functional disablement.
  14. Whether a change of the setting of the CONTROL REPRESENTATION MODE affects the appearance of control functions already entered into, or received by, the device or whether only those entered or received subsequently.
  15. Whether or not the characters in an eligible area are transmitted in the data stream or transferred to an auxiliary device when the eligible area begins in the middle of a guarded area.