Full-screen mode

The application program controls screen management in full-screen mode. The primary (small) screen size is considered by TSO/VTAM as the default size. The application program can control screen size by sending write commands in TPUTs that it issues. The write commands are X'F5', erase write, and X'7E', erase write alternate. The application program issues X'F5', erase write, to set the primary screen size, or X'7E', erase write alternate, to set the alternate (large) screen size.

If neither command is issued, the screen remains the size it is when the application program enters full-screen mode.

Line mode

TSO/VTAM controls screen management in line mode. It generally uses the large (alternate) screen size when processing TPUTs in line mode. You can use the TSO TERMINAL command STSIZE macro during a session to change the screen size for nonfull-screen processing.

Using output from the VTAM® full buffer contents trace, the TGET/TPUT trace for TSO/VTAM, and the GTF trace of the SVC 93 and SVC 94 entries, try to locate the source of the problem.

1. Check the SVC 94 trace entries to see whether the processing is in full-screen mode or line mode.The STFSMODE and STLINENO macros set these modes on and off.

   If the processing is in line mode, go to step 6. For full-screen mode, continue with step 2.

2. Note if the incorrect screen size is related to entering or exiting full-screen mode.
3. Locate the TPUT trace entry for the data that appears on the screen when the screen is the wrong size.Determine the TPUT options for this TPUT and the one that precedes it by looking at the option flag bytes.

   If either is a full-screen TPUT, look at the first data byte.

   If the first data byte is an escape character (X'27'), the write command that follows has been specified by the application program. This write command should determine the screen size.

   If the write command is different in the buffer contents trace, go to Reporting the problem to IBM.

4. If the first data byte is not an escape character, determine whether a write command (X'F1', X'7E', or X'F5') is provided.

   If one of these write commands exists, continue with this step.

   If not, go to the next step.

   If this write command is different in the VTAM buffer contents trace, go to Reporting the problem to IBM.

   If the same write command is displayed in both traces, contact the group responsible for the application program.

5. If a write command is not provided in the TPUT data, and processing is in full-screen mode, determine if the write command generated by TSO/VTAM set the same screen size as the last write command provided by the full-screen application program.To determine this, compare the write command in the buffer contents trace entry with the last one provided in a TPUT trace entry. The write command is located in the data portion of the TPUT trace, at X'2C' into the entry.

   If the write commands are the same, go to Reporting the problem to IBM.

   If the write commands are different, contact the group responsible for the application program.

6. If processing is not in full-screen mode, determine whether the STSIZE macro set the screen size.To determine this, look in the SVC 94 trace entries. An entry code of X'0A' in the high-order byte of register 0 indicates that the STSIZE macro set the screen size.

   If the screen size was set by the application program, contact the group responsible for the application program.

7. If you have not resolved the problem, go to Reporting the problem to IBM.