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General description of the Connection Handler
The Connection Handler is a utility that allows multiple tasks to be carried out in parallel on a terminal, whereby each task has its own exclusive screen.
Connections in CFS are DCAM applications that communicate with, for example, $DIALOG or UTM applications.
Dialog via a CFS-Connection takes place in the same way to which users are accustomed. Only the initiation of a Connection in CFS differs from the original method of connection.
Instead of issuing an Open Command in Predialog, an Open Connection Command (OC...) is entered in the command field of CFS.
The following additional services are available to the user through the CFS Connection Handler:
1) Multiple parallel dialog sessions can be executed from a single terminal
2) Recording (Logging) and replaying (Restore) of dialog sessions
3) Regression test (Comparison of an actual dialog with a recorded dialog)
4) Simulation of recorded dialog sessions
5) Mask-controlled hardcopy of a dialog session (including UTM applications) to a printable file
6) Command memory: Reactivate previous user input
7) Prompting for parameters via a mask when starting DO procedures
Administration of the various dialog sessions is effected by the commands OC (Open Connection), CC (Continue in Connection) and DC (Disable Connection).
10 Connections (OC0 to OC9) can be opened per user.
In the following text, n stands for a Connection-Number 0 to 9.
Instead of OCn... and CCn, the shorthand n... and n can be used. Should no connection exist, the command executed is OCn, otherwise CCn.
Following a successful Open Connection, the user is connected with the requested application. In the case of a dialog session, a task with its own TSN is started under the requested user identification. Communication with the opened connection proceeds via CFS. Ending the program CFS will result in all connections opened via CFS being lost.
If the communication with a subtask needs to be interrupted, for example after starting a lengthy program or DO procedure, then press the K2-Key. The user can now switch to the basic CFS task, or to another connection. The user can resume communication with the open applications at any time by issuing the command CCn (Continue in Connection). Any messages received in the interim for that connection is buffered by the Connection-Handler and are all displayed on the screen following the CC command.
$CONSOLE: Connections to $CONSOLE result in all applicable console messages appearing on the screen as freerunning text. The user can input messages to the console by pressing the K2 key, and then entering the command when requested. Console commands like STA MSG can be given both in the full /STA MSG form as well as in the shortened STA MSG form. The command /TCHNG OFLOW= can also be given in a connection to $CONSOLE in order to control screen overflow.
Additional notes to Connections:
Screen output which is interrupted by the "Please Acknowledge" message must be completely displayed within the time set by the system administrator in the BS2000 command /BCTIMES LETT=. The connection will be cleared down (Connection Lost) is this does not occur.
CFS interprets any of the following input as internal commands, and therefore they are not passed to the communication partner: LOG / NLOG / RES / HC / NHC / - / -- / ^.
If CFS is loaded from a connection, and then another connection is opened from here, (Connection Level 2), there is an overlap if the same escape symbol is used between Level 1 and Level 2. If CFS is loaded from a connection, the alternative escape symbol ` (X'4A') is automatically used. If the user is in a connection in Level 2, the escape symbol ^ will return him to the CFS level that was first loaded i.e. Level 0. Entering the symbol ` will return him to the level from which this CFS was loaded i.e. Level 1. It makes sense, therefore, to leave nested connections by using the alternative escape symbol.
With regard to nested connections, it should be noted that pressing the K2 key in Level 2, and then entering R (Return) will return you to that level of CFS which was originally loaded (Level 0), and not to the level immediately below you (Level 1). Later, a command CCn will not enable CFS in Level 1, rather in the Level 2 that you left with K2. Pressing the K2 key and entering B (Break) in a connection in Level 2 will result in CFS in Level 1 returning its connection request "Return / Continue in Conn. n / Break ...".
Transmitting a HC-, LOG-, RES command in a nested connection will always result in the basic CFS task (Level 0) processing the command. LOG and hardcopy files are also always created in the userid from which CFS was called for the first time.
The symbol to activate the command memory (see next section) can be redefined for each connection level seperately by means of the CRD (Connection Command Redefine) command. The CRD command to change the symbol for all connections within a level should be entered in the command line of the CFS task that is directly controlling the affected connections, i.e. those in the level immediately below.
The processing of all CFS connection-specific commands such as HC, LOG, RES can also be prevented for a specified Connection x at Level n. To achieve this, enter the CFS command NEC x (No Exit for Connection x) at Level n-1.