Most ISPF users are familiar with the F2 SPLIT key and the F9 SWAP key. These keys are used to create a second ISPF session and switch between two ISPF sessions.
The F2 SPLIT command will create a second session and split the screen at the current cursor line. To get a full screen split, you would use the arrow keys to position the cursor at the top or bottom line of the display, then press F2.
To reposition the split, you move the cursor to a line on the screen and press F2 again.
The START command will always perform a full screen split, regardless of the cursor position and it automatically allows multiple split sessions (minimum of 8 sessions, some sites support 32).
Another benefit to the START command is the ability to use it with a command or ISPF option.
START DSLIST *
Would start a new full screen session with a list of data sets matching your TSO PROFILE PREFIX.
START 11 or START ISPFWORK
Would start a full screen session with the ISPF WORKPLACE.
Managing split sessions:
Each new session you split to using the START command is numbered.
To see a list of all the sessions use the command: swap list
You can use the "swap list" to choose a session by putting your cursor on the . (period) to the left of the session and pressing "enter".
You'll also see that one session is marked with a - (hyphen) and one is marked with an * (asterisk). The * session is the current focus of your ISPF display. The - session is the alternate screen that is switched to when the F9 Swap key is pressed.
Pressing F9 Swap will only switch between the two marked sessions.
Without using the "swap list", you can:
Move to the next logical session use the command: swap next
Switch to a specific sessions use the command: swap number
Remember that F key commands are combined with the ISPF command line, so:
number (on the command line) + F9 = swap number
next (on the command line) + F9 = swap next
list (on the command line) + F9 = swap list
Give it a try and have fun!