gtpd2m0m | Data Communications Services Reference |
The CRAS package is designed to support varying levels of system control based on individual installation requirements. The support is flexible; minimal or maximum control can be exercised based on an installation's specific needs. The level of control is based on how the system is initially configured and installed, but may change during online operation as dictated by system activity. The extent to which the level of control may be changed dynamically is also based on initial system configuration.
System control is provided through the installation's use of the following functions:
Commands are accepted into the system only from the system console and from alternate CRAS devices. The user can therefore limit access to the system by limiting the number of terminals defined as alternate CRAS terminals.
Each command carries with it a set of indicators which describes its processing characteristics, many of which pertain to controlling the system in a loosely coupled and/or multiple data base function environment. These characteristics include the following:
Any or all commands may carry the classification of restricted. Restricted messages are only accepted into the system from alternate CRAS sets which have been authorized to do so. The system operator controls which terminals are granted such authorization; he may grant or rescind such authorization dynamically to satisfy varying levels of system activity.
Historically, since the system console was usually a 1052/3215 hardcopy device, the RO was used for unsolicited messages and noncritical system messages. With FSC support virtually all system activity is now logged to some hardcopy device, yielding a complete log of system activity. In addition, the user may separate this hardcopy log by functional classification, in any combination he sees fit. The released code supports the following functional categories: PRC, RO, TAPE, DASD, COMM (communications), and AUDT (audit trail). The audit trail has been defined to receive a copy of all output. This provides a chronological log of all system activity. See Addition Of A New FSC Name for the procedure to be followed to change or add to these functional categories.
Every IPL of the system saves the status of the system consoles. For a system generated with 1052 console support, a 1052/3215 device or a 3270 CRT/PRT pair must be available upon every IPL. Alternatively, for a system generated with 3270 native console support, a 3270 local CRT must be available upon every IPL.
A system IPL can also affect messages destined for FSCs. After an IPL, messages will not be sent to FSCs which are other than 1052 or local 3270 devices until the system is cycled to CRAS state. Such messages will be sent to the RO instead. (Also note that messages on queue for these devices when the system undergoes an IPL will be held until the queue is reactivated in CRAS state.)