*stars #H break
*ibm #H 370
*370 #H 370
*ibm370 #H 370
*command
**
STAR command
Form:           STAR   "Machine,Service/K,Text/K,Quality/K,NOTAUTH/S,MINADDR/S"
Purpose:        To connect into an interactive ring service using VTP.
Author:         BJK (modified by CGG)
Specification:

        The RATS protocol (Virtual Terminal Protocol) is used to connect to
    the RING service "RATS-<Machine>", or, if the SERVICE key word is given
    in preference to the MACHINE keyword, to the ring service "<Service>".
    The initial connection is by the Cambridge version of a TSBSP open (see
    "Byte Stream OPEN Blocks" by MAJ - 25.10.82, in the documentation
    folder).  This open will include the user's UIDset unless the NOTAUTH
    switch is given.  The "informative text" parameter of the CONNECT message
    in the open can be set using the TEXT keyword and the "quality of
    service" using the QUALITY keyword.  Note that implementations currently
    available in the Lab will expect neither of these to be set.  The address
    used to identify the caller when the connection is established can, under
    normal circumstances, be quite long.  Strictly this address should be only
    one character long in the current version of VTP accepted by the terminal
    concentrators - the switch MINADDR can be used to enforce this rule.

        This program is also used to support reverse connection into TRIPOS.
    Reverse connections are accepted from the Ring and come up completely
    ignorant of any STAR command that may have caused their existance.  When
    it does come up it switches the default input stream to its own task,
    leaving the initiating STAR command still active, but in another task.
    When this task eventually ends it reselects the task that it interrupted
    to be the default input stream.
    
        The communication ceases and the command ends when either the stream
    ends or the user uses CRTL-D (or BREAK B D).
    
        CTRL-B and CTRL-C will echo these characters onto the VTP interface    
    of the RATS service - which will give the correct effect if another
    TRIPOS has been logged onto.
    
        CTRL-E is used to enter the STAR monitor which allows nonstandard use
    of the RATS stream, such as sending uninterpreted characters and
    characters to the VTP interfaces (for example, it can be used to get
    CTRL-S and CTRL-T through to a destination TRIPOS).  Unfortunately, the
    monitor can only be entered after the completion of a line of input: the
    whole of the line in which CTRL-E is typed will be sent except for the
    newline or escape that terminates it.  Thus this facility can be used to
    insert curious characters into the middle of a line. STAR allows a second
    way to enter the monitor:  if the escape string is typed on a line of its
    own the characters that form it will not be sent to the destination
    service and the monitor will be entered.  The default value of this
    string is "*!" but it can be changed by a monitor command. A list of
    monitor commands is given in response to the command '?' in the monitor. 

Examples:

        STAR cap
        STAR udn NOTAUTH
        STAR udn/s.rlgb   {logs onto a GEC at Rutherford Appleton Labs}
        STAR SERVICE gec*rats-fermat TEXT "Connection from Cambridge"

        {the following demonstrates how a line consisting of the characters
         "abcdef<control-P>hijk" can be sent to the service RATS-XSERV}

        STAR xserv
        xserv: abcdef<control-E><carriage return>
        Star> cu p
        Star> s
        hijk
        xserv: received "abcdef<ctrl-p>hij"

        {note that <control-E> could have been typed ANYWHERE on the
         "abcdef.." line with exactly the same effect}
 
        {.. and this demonstrates how <CTRL-S> can be sent to the VTP
         interface of service RATS-XSERV (this is how @S works if XSERV
         is provided by TRIPOS) - }
        
        STAR xserv
        xserv: *!
        Star> ci s
        @S
*
  

