Unformatted system services tables
VTAM® uses unformatted
system services (USS) tables to:
- Issue messages to the VTAM operator console or a program operator application
- Process VTAM operator commands
- Issue messages to a terminal operator user
- Process commands received from a terminal operator user
Other messages, such as TSO/VTAM messages, are provided through other facilities. For an explanation of these messages, see z/OS Communications Server: SNA Messages.
VTAM uses two types
of USS tables to define messages and commands:
- Session-level table
- Contains:
- Definitions for terminal user commands (such as LOGON) that can be received from a terminal.
- Messages that VTAM sends to a terminal.
- A translation table that is used for character-coded input from the terminal.
- Operation-level table
- Contains USS commands (such as DISPLAY ROUTE) that can be received from the VTAM operator or a program operator application and messages issued in response to those commands. See Operation-level USS table (ISTINCNO) for an example of an operation-level USS table.
IBM® supplies default USS tables with the VTAM product. The source language for these tables is contained in SYS1.ASAMPLIB. Table 1 describes the default tables.
Table name | Description |
---|---|
ISTINCDT | Default session-level USS table used
by terminal operator users. Contains the following
items:
|
ISTINCNO | Default operation-level USS table
used by the VTAM operator (commands
and messages) and program operator applications (commands). Contains
the following items:
|
ISTCFCMM | Default operation-level USS table for a program operator application containing operation-level VTAM messages. |