gtps4m1mSystem Generation

Unsolicited Message Support

The unsolicited message package (UMP) is a group of programs that handle unsolicited messages to terminals or logical units logged to old applications. A message is defined as unsolicited when it is not generated as a response to an input message. Unsolicited messages originate at a terminal/logical unit or in a program in a TPF processor or non-TPF processor. The destination may be either a terminal/logical unit or a group of terminals/logical units (the latter is referred to as a broadcast message). Routing variations are as follows:

The unsolicited message package uses unsolicited message directories (see data macro CO1DR) to maintain references to unsolicited messages until they are successfully transmitted or are purged as redundant items as a result of a disposition request. The CODR directories are organized by terminal or logical unit.

When processing an unsolicited message, a reference item is created and inserted into a directory record. The directory record is retrieved using the address of the destination terminal or logical unit to calculate the needed ordinal number in the directory's record type. A reference item contains information such as:

There are 4 prime CODR records that are allocated as program records via SIP. Additional records are acquired as needed from the random pool. Initialization for prime and overflow records is handled by an unsolicited message package component program.

Broadcast messages require the creation of reference items for the addressed terminals and the propagation of the message to all other TPF processors in the network. For all broadcast messages except those routed to units of a specific application, the unsolicited message package uses the WGTA, which is created from the user-specified UAT (see Communication Pilot Record Generation) for routing to terminals that have a valid LNIATA or pseudo-LNIATA (3270/SDLC and NEF terminals).

Terminals logged to SNA applications, those that use SNA resource identifiers (RIDs) to identify SNA resources, are specifically excluded from receiving unsolicited messages by this package. This is because this package and the TPF system itself do not control the screen format in use by the terminals in the application. Therefore, it is not safe for this package to change the screen format from what the application itself thinks is on the screen or in the buffer of the terminal. If a user wants to send unsolicited messages to these logical units, the user must write an application program to perform this function.

In order to schedule delivery of these messages, UMP maintains the unsolicited notification list (see data macro CO3NL) containing references to each receiving terminal or logical unit. For broadcast messages, notification is sent to the terminal immediately.

For nonbroadcast messages (single messages) the destination terminal is immediately notified if the origin of the message is the same application to which the terminal is connected or the terminal is idle.

After receiving notification of existing unsolicited messages, the terminal operator may either temporarily disregard the notice or immediately request a display of the message.

A third functional component of UMP will, on a time initiated basis, police the unsolicited message directory (CODR) to again advise terminal users of unsolicited messages queued for the terminal. This policing function will also purge out of the system any messages not displayed after several attempts at notifying the terminal user. The purge function may also be initiated by a direct request from the terminal user.