Single Console Image Facility (SCIF)

By means of the single console image facility (SCIF), a user logged on to a single virtual machine can control one or more disconnected virtual machines. The controlling virtual machine is called the secondary user. A disconnected virtual machine being controlled is called a primary user.

After a primary user is under the control of a secondary user, the secondary user can enter input on behalf of the primary user by way of the CP SEND command. CP redirects the output for the primary user to the console of the secondary user, prefixing it with the primary user's user ID. Note that the single console image facility can be used only by users whose consoles operate as 3215s, as established by way of the CONSOLE directory statement or the TERMINAL CONMODE command.

A virtual machine is defined as a primary user by specifying on the CONSOLE statement in its z/VM® directory entry the user ID of the secondary user by which it is to be controlled. This statement authorizes the secondary user to control the primary user by way of the single console image facility.

The secondary user receives control of the primary user when the primary user disconnects. If the secondary user is logged on, it receives control immediately. Otherwise, it receives control when it is next logged on, if the primary user is still disconnected. The primary user can regain control at its own display by using the LOGON command. When logged on, the primary user can use the SET SECUSER command to change the secondary user ID associated with its virtual machine. The primary user can also use the QUERY SECUSER command to determine the identity of its authorized secondary user.

After the primary user has disconnected, all console output not in full screen form from the primary user appears on the console of the secondary user (if logged on). Output from the primary user contains the user ID of the primary user. The prefix allows the secondary user to distinguish output from each of the primary users it controls.

The secondary user uses the CP SEND command to communicate with the primary user. The SEND command can be used to enter CP commands, virtual machine commands, responses to virtual machine or CP messages, or other virtual machine data as required on behalf of the primary user. For example, when a message indicates that the primary user has entered CP READ mode, the secondary user can use the SEND command to enter a CP command on behalf of the disconnected primary user. Similarly, when a message indicates that the primary user has entered VM READ mode, the secondary user can use the SEND command to enter the required virtual machine command or response on behalf of the disconnected primary user.

The console attributes of the secondary user are used for the display of messages. For example, if the primary user's console is spooled with the TERM option and the secondary user's console is spooled with the NOTERM option, only the messages allowed by the NOTERM option are displayed on the secondary user's console.

If the secondary user has a valid path to the message system service (*MSG) or message all system service (*MSGALL), it may run disconnected. Output on behalf of the primary user normally directed to the secondary user's console is instead directed through IUCV to one of these CP system services. For more information, see *MSG System Service and *MSGALL System Service in the z/VM: CP Programming Services.

The single console image facility is useful for monitoring and operating an application running in a disconnected virtual machine. It allows multiple service virtual machines (such as those in which RSCS, the VM/Pass-Through facility, and the CMS batch facility run) to be controlled from a single real display. In addition, the primary system operator can use a single real display to control both the z/VM system and one or more production or test virtual machines.