Get the Big Picture

Are you still working on VOS using a 80 column by 24 line view?  Get with the flow and see the big picture.

VOS supports many terminals and terminal emulators.  Stratus supplies terminal-type files (“ttps”) for over 100 terminals or emulators.  They all default to 80×24 views, but it is easy to change to a bigger view.  Most ttps contain a “setup” section that lists the acceptable screen configurations.  For example, if you are using the v103 ttp, either on a real terminal or in an emulator such as TTWin, type the following command line:

!set_terminal_parameters -setup 132x42

This command will dynamically change your screen to have 132 columns and 42 lines.  You may need to put on your glasses, or resize the emulator window to more easily read the characters.  If your emulator supports all of the features of the v103, it should have no problem running with the larger view.

Note that the 132×42 view can hold 2.8 times as many characters as a 80×24 view.  I find that I can get a better understanding of my software, and be more productive, with the larger view.

The largest views are supported by the putty, teraterm and tinyterm emulators.  They offer a massive 132×65 view, which displays 4.5 times as many characters as 80×24.  These emulators are capable of resizing the window under host control – In other words, when you change the setup they will automatically resize the PC window.  These emulators are not confined to the views defined in the terminal types:  If you need another view size, you can edit the setups in the terminal type file to use other sizes (up to 255 x 255).

I am not aware of any method to list the available setup parameters other than reading the ttp itself.  Fortunately, we ship the source files for the ttps in the (master_disk)>system>sample_programs>supported_ttps directory.  You can simply pick them up in an editor and search for the “setup” keyword to see which ones are available, or use “display -match setup” or “grep setup” to find the appropriate lines.

If you are using openssh, you can resize the windows on the PC (or Linux system) and have VOS track the window size changes.  This feature is enabled by the screen-can-be-resized option in the terminal type files.  The full_xterm, putty_aws, tinyterm, ttwin_aws and xterm terminal types currently have this option.

The following table shows the combinations of emulator and terminal type that will allow VOS to resize the window (for telnet) or that will track window resizing by the PC (for OpenSSH).

Command line processing even readjusts on the fly when the screen size changes.  Screen oriented applications may need to be restarted in order to notice the screen has been resized.

Some older terminals and emulators may only support using more columns and not more lines.  This is particularly true with the DEC “vt” series of terminals, i.e., the vt100, vt220 and vt320.  But you may find that if you switch to a ttp for a newer DEC terminal (i.e., the vt510) that your emulator can indeed handle the additional features necessary to increase the number of lines as well as the number of columns.

If your emulator can’t support the bigger views, then I recommend that you find a new emulator.  Once you use the larger views, you will never want to go back.

Dan Danz and Herbie Robinson contributed to this article.