Limited supportBMC provides limited support for this version of the product. As a result, BMC no longer accepts comments in this space. If you encounter problems with the product version or the space, contact BMC Support.BMC recommends upgrading to the latest version of the product. To see documentation for that version, see BMC AMI Ops Infrastructure 7.1.

Terminal Address Space TAS functions

A TAS is required for each user session, whether VTAM or EXCP. However, a TAS cannot support both modes in a single session.

Up to 32 EXCP TAS sessions can run concurrently on a system, along with any number of defined VTAM sessions. The EXCP 32-session maximum is an artificial limit that is set internally by MainView Alternate Access. The maximum number of VTAM sessions that can run is determined by the number of defined minor nodes; the default number is 10.

Note

If your site requires more than 32 concurrent EXCP sessions, contact BMC Support.

Operational considerations

The following considerations apply:

  • For VTAM sessions, VTAM must be available and the MainView Alternate Access VTAM application major node must be active before a TAS can be started (see Activating-the-VTAM-application-major-node for more information).
  • For EXCP communications, the terminals for EXCP sessions must be inactive on the VTAM network before a TAS can be initialized (see Inactivating-a-VTAM-terminal-for-EXCP-communications).
  • Each TAS must run as a started task.
  • The priority of each TAS should be set above priorities for batch jobs that are running in your system and should be set similar to priorities for the BMC online components.
  • The started task for each TAS is created at session initialization and is terminated when any of the following conditions occur:
    • The user logs off.
    • An operator issues an MVS STOP or cancel command from the console for the address space.
    • The VTAM connection to the terminal is interrupted due to a VTAM shutdown.
    • The terminal is shut down.
  • A TAS initializes when a START command is issued
    • By the LAS because of a user logon
    • By an operator
    • By an automation or scheduling product
    • During the IPL procedure

Initialization parameters

When a TAS initializes, it reads parameters that define the session environment from a parameter library (parmlib) member, from the proc, and from the START command, if defined.

If appropriate logon parameters are defined in one or more of these locations, a session on a specific terminal can be established without any user intervention. When a TAS’s session parameters contain OPT( ) and the session initializes directly into an application, the session is known as an AutoLogon session.

For example, if the OPT( ) subparameter is specified with other appropriate logon parameters, a customized character string that is defined to OPT( ) gets passed to ISPF at session initialization. ISPF processes this character string to display a product menu, service, view, or screen.

EXCP sessions require that all logon parameters be defined to parmlib, the proc, the START command, or a combination of all three places because logon services are not provided for EXCP communications. However, you do not have to define all logon parameters for VTAM sessions. In fact, LAS-issued START commands typically contain only the terminal LU name and the user ID values.

Session security

During session initialization, the TAS checks with the external security manager (ESM) to see whether log on credentials are required for the specified user ID.

If a credentials are required, the TAS passes the credentials to the SAF interface for verification by the ESM.

In the case of an EXCP or an AutoLogon session start, the session fails if the user ID value is invalid. The TAS displays the credentials panel if the password value is invalid or if a required credentials have not been provided.

Depending on the access method used, MainView Alternate Access supports the use of passwords, passphrases, and IBM Multi-Factor Authentication for z/OS (IBM MFA).

BBVINIT REXX EXEC

Each TAS uses the BBVINIT REXX EXEC, which

  • Provides flexible allocation of ISPF data sets and creates the ISPF environment
  • Executes the MainView CLIST for the Selection Menu

BBVINIT can allocate the ISPPROF profile data set for each TAS, if BBVINIT detects that the data set does not exist at logon. The BBVINIT REXX EXEC contains naming suggestions to help avoid a potential conflict at session initialization if the user is concurrently logged on to TSO with the same user ID.

Note

Although a different ISPPROF data set allows the same user to be logged on to TSO and MainView Alternate Access simultaneously, restrictions in MainView Infrastructure architecture might restrict MainView access to either TSO or MainView Alternate Access. If you are using only BBI-3 products, this restriction does not exist.

Initialization sequence of events

The following sequence of events occurs during TAS initialization:

  1. The TAS is started by the LAS for a VTAM terminal user logon; by a START command that is issued by an operator; by an automation or scheduling product; or during the IPL procedure.
  2. The TAS verifies the user ID with the ESM through the SAF interface.
  3. For VTAM access, the TAS displays the password panel if required.
  4. The TAS verifies the credentials with the ESM through the SAF interface.
  5. Upon receiving verification from the ESM, the TAS invokes BBVINIT to:
    1. Allocate session data sets.
    2. Start ISPF for the session.
    3. Execute the MainView CLIST.

Note

MainView Alternate Access VTAM sessions support the use of passwords, passphrases, and IBM Multi-Factor Authentication for z/OS (IBM MFA). All other methods support passwords only.

Related topic

MainView-Alternate-Access-architecture

 

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