Interprocess Command Interpreter Messages - HP Guardian Errors Manual

19 Interprocess Command Interpreter Messages

Application processes use Tandem Advanced Command Language (TACL) to send or receive the
messages described in this section. The TACL product is the command interpreter supplied by HP
for use on the operating system.
Though user-written command interpreters can be used, in this section the TACL product is assumed
to be the only command interpreter. If a user-written command interpreter is in use, read "command
interpreter" instead of "TACL" in the following messages.
The interprocess command interpreter messages described in this section should not be confused
with the system messages described in
share many of the same message numbers, the command interpreter messages do not generate a
file-system error 6 (system message received) as do the system messages.
Command interpreter messages are not error messages; they are used to convey information.
When a request for a new process occurs, such as from a PROCESS_CREATE_ procedure call, the
operating system creates a new process. When the process is created, a message is sent to it by
the TACL process. This message is called the startup message. The startup message carries an
indication of any ASSIGN or PARAM messages to be added. (ASSIGNs and PARAMs establish
certain characteristics of the new process.) When there are no more ASSIGNs or PARAMs to be
processed, the newly created process is ready to be accessed.
Figure 2 illustrates the communication between an application process, the TACL process, and
$CMON.
Figure 2 Command Interpreter Messages
Messages - 1 , -2, and -3 are sent by the TACL process to processes that it creates. Messages -20
and -21 are sent by any process to the TACL process.
Messages -50 through -60 are sent to $CMON, but not all of these messages are sent by the TACL
process. ADDUSER, DELUSER, PASSWORD, and RPASSWORD are privileged, licensed programs;
they send their messages to $CMON. When $CMON is running, these programs add an additional
level of access restriction to the operating system. When $CMON is not running, their restrictions
are not in effect.
The first word of each $CMON message is usually a control word that permits or disallows an
operation. For most $CMON messages, the rest of the reply is text that the TACL process displays.
It typically contains the reason why $CMON did not permit the operation. $CMON messages are
also used to display the greeting at LOGON or a farewell message at LOGOFF. Two exceptions
are the command interpreter messages -52 (run) and -60 (configuration); these allow $CMON to
return information or to display text. If the first word is zero, the rest of the reply contains data; if
the first word is nonzero, the rest of the reply contains text to be displayed.
The sources of the interprocess command interpreter messages are shown in
Table 12 Command Interpreter Messages
CI Message
- 1 Startup
-2 Assign
-3 Param
-20 Wakeup
-21 Display
"System Messages" (page
Source
Sent by TACL process to the process it created
Sent by TACL process to the process it created
Sent by TACL process to the process it created
Sent by any process to TACL process
Sent by any process to TACL process
246). Though these messages
Table 12.
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