dsinfo File

Purpose

Contains the terminal descriptions for the Dynamic Screen utility.

Description

The dsinfo file is a database of terminal descriptions used by the Dynamic Screen utility. A terminal description typically contains the following configuration information:

Keys defined for specific use with the Dynamic Screen utility and their function
Number of pages of screen memory available to the terminal
Code sequences that must be sent or received to access and use Dynamic Screen features

The dscreen command reads the appropriate configuration information from the dsinfo file to start the Dynamic Screen utility.

Entry Format

Line entries in the dsinfo file consist of a number of definition fields separated by commas. The first-line field entries are alternate screen names for the terminal. The screen name fields are separated by a | ( pipe symbol).

Other line fields are strings describing the capabilities of the terminal definition to the Dynamic Screen utility. The following escape codes are recognized within these strings:

Escape Code	Meaning
\E,\e	Escape
\n,\l	New line
\r	Carriage return
\t	Tab
\b	Backspace
\f	Form feed
\s	Space
\nnn	Character with octal value nnn
^x	Ctrl-x for any appropriate x.

Any other character preceded by a \ (backslash) yields the character itself.

Strings must be entered as the type=string parameter, where type is the string type and string is the string value.

If information is not entered into a string field, a comma is still used to designate the existence of the field.

String Types and String Values

The following string types are available:

String Type	Meaning
dskx	Describes the action assigned to a key. This string type contains 4 characters. The 4th character indicates the action to be taken when the keystroke is received by the screen:

Key Type	Action
dskb	Block input and output.
dskc	Start a new screen.
dske	End the Dynamic Screen utility (exit code 0).
dskl	List keys and actions.
dskp	Switch to previous screen.
dskq	Quit Dynamic Screen utility (exit code 1).
dsks	Select a specific screen. Currently, the only valid dsk string type endings are b, c, e, l, p, q, and s. Any other key definitions used at this time are interpreted as null values and cause no internal Dynamic Screen action for the terminal definition. Other keys may be assigned values within the Dynamic Screen utility at a later time. Note: The dskn string type (n for null or no operation) is guaranteed not to be used for any function assignments in future versions. It is recommended that the dskn string type be used instead of other null characters when no internal Dynamic Screen action is desired for a terminal definition. The value string for each dskx string type has three substrings, separated by a \| (pipe symbol). (To include a `\|` in one of the substrings, use `\\|` [backslash, pipe symbol].) The first substring is the sequence of characters the terminal sends when the key is pressed. The second substring is a label for the key as displayed in the key listing (for example, the Shift-F1 key sequence). The third substring is a sequence of characters the Dynamic Screen utility sends to the terminal when the key is pressed, before performing the requested action.
dsp	Describes a physical screen in the terminal. A dsp string type must be present for each physical screen in the terminal. The value string for each physical screen has two substrings, separated by a `\|` (pipe symbol). (To include a `\|` in one of the substrings, use `\\|` [backslash, pipe symbol].) The first substring is the sequence of characters to send to the terminal to display and output to the particular named physical page on the terminal. The second substring is usually set to clear the screen sequence. It is sent under the following two conditions: The creation of new terminal session More terminals are running than there are physical screens. If your selection of a terminal causes the Dynamic Screen utility to reuse one of the physical screens, the clear-the-screen sequence is sent to the screen to indicate that the screen content does not match the output of the terminal connected to it. Note: Running with more terminals than there are physical screens is not recommended. Avoid this situation by defining no more screen selection keys (`dsks=`...) than physical screens (`dsp=`...).
dst	Adjusts the Dynamic Screen utility's input timeout. The value of the string must be a decimal number. The timeout value is in tenths of a second and has a maximum value of 255. The default timeout value is 1, or one tenth of a second. When the Dynamic Screen utility recognizes a prefix of an input sequence but has not yet received all the characters in the sequence, it waits for more characters. If the timeout occurs before more characters are received, the received characters are sent to the screen, and the Dynamic Screen utility does not consider these characters as part of an input key sequence. Consider increasing the value of the dsp string if one or more of the keys to which the utility has to respond is actually a number of key combinations (for example, <Ctrl-Z> 1, <Ctrl-Z> 2, <Ctrl-Z> 3, and so on, for screen selection, or <Ctrl-Z> N, for new screen).

Examples

The following dsinfo entry describes a WYSE 60 terminal with three screens:
```
wy60|wyse60|wyse model 60,
   dsks=^A`^M|Shift-F1|,
   dsks=^Aa^M|Shift-F2|,
   dsks=^Ab^M|Shift-F3|,
   dskc=\200|Ctrl-F1|,
   dske=\201|Ctrl-F2|\Ew0\E+,
   dskl=\202|Ctrl-F3|,
   dsp=\Ew0|\E+,
   dsp=\Ew1|\E+, 
   dsp=\Ew2|\E+, 
```
The <Shift-F1> through <Shift-F3> key combinations are used for selecting screens 1 through 3. <Ctrl-F1> creates a new screen. <Ctrl-F2> sends the key sequence <Esc> w 0 <Esc> + to the screen. As a result, the terminal switches to window 0, the screen is cleared, and the Dynamic Screen utility ends. <Ctrl-F3> lists the keys and their functions. The three physical screens are displayed by sending the key sequences <Esc> w 0 , <Esc> w 1, and <Esc > w 2, respectively. Each time a physical screen is used for a new screen the <Esc> + key sequence is sent to the terminal to clear the screen.
The following dsinfo entry describes a WYSE 60 terminal with three screens, one of which is on a second computer communicating through the second serial port on the terminal. The Dynamic Screen utility must be run on both computers, with terminal type WY60-1 on the first computer and terminal type WY60-2 on the second computer (to do so specify the -t flag in the dscreen command).
```
wy60-1|wyse60-1|wyse model 60 - first
serial port
   dsks=^A`^M|Shift-F1|,
   dsks=^Aa^M|Shift-F2|,
   dskb=^Ab^M|Shift-F3|\Ed#^Ab\r^T\Ee9,
   dskc=\200|Ctrl-F1|,
   dske=\201|Ctrl-F2|\Ed#\201^T\Ew0\E+,
   dskl=\202|Ctrl-F3|,
   dsp=\Ew0|\E+,dsp=\Ew1|\E+,
wy60-2|wyse60-2|wyse model 60 - second
serial port
   dskb=^A`^M|Shift-F1|\Ed#^A`\r^T\Ee8,
   dskb=^Aa^M|Shift-F2|\Ed#^Aa\r^T\Ee8,
   dsks=^Ab^M|Shift-F3|
   dskc=\200|Ctrl-F1|,
   dske=\201|Ctrl-F2|\Ed#\201^T\Ew0\E+,
   dskl=\202|Ctrl-F3|,
   dsp=\Ew2|\E+,
```
The first two key entries for terminal type WY60-1 are identical to the entry in example 1. The third key entry, of type dskb, specifies that input and output are blocked when the <Esc> d # <Ctrl-A> b <CR> <Ctrl-T> <Esc> e 9 key sequence is sent to the terminal. As a result, output is blocked, and the Dynamic Screen utility continues to scan input for key sequences but discards
all other input. The <Esc> d # sequence puts the terminal in transparent print mode, which echoes all keystrokes up to <Ctrl-T> out the other serial port. The <Ctrtl-A> b <CR> key sequence is sent out to the other serial port, informing the Dynamic Screen utility on the second computer that it should activate the window associated with the <Shift-F3> key. The <Ctrl-T> key sequence takes the terminal out of transparent print mode, and the <Esc> e 9 key sequence informs the terminal to switch to the other serial port for data communications.

The other computer takes over and sends the <Esc> w 2 key sequence to switch to the third physical screen and then resumes normal communication.

The WY60-2 entry follows the same general pattern for the <Shift-F1> and <Shift-F2> key combinations, which switch to transparent print mode, send a function key string to the other computer, switch transparent print off, and switch to the other serial port.

The end key <Ctrl-F2> works the same for both computers. It sends the end key sequence to the other computer through the transparent print mechanism, switches the terminal to window 0, clears the screen, and exits.

Files

Item	Description
/etc/dsinfo	Contains the terminal descriptions for the Dynamic Screen utility.