Guest Target Systems

The most likely guest machine that is used as a target system is a LINUX system. When a LINUX machine has a secondary user, the secondary user can use CP SEND commands to:

  • Issue CP commands to the guest machine
  • Log on as a user to LINUX
  • Enter LINUX commands (after logging on)

(It is also possible to set up the LINUX system in such a way that LINUX commands can be entered on the VM console without logging on to LINUX.)

The secondary user receives:

  • All "boot up messages"
  • Responses to CP commands that are run on the guest machine
  • Responses to logon and LINUX commands

MVS machines are more complex. When an MVS machine is running, the original VM user first becomes an NIP console and then an MCS console. In these console modes MVS takes over all I/O to and from the console, and MVS messages to it cannot be intercepted by any CP facilities. Hence the SCIF SEND command cannot be used to send commands to MVS, nor can MVS messages to this console be intercepted.

However a "virtual SCLP console" for the guest machine can be used. During the NIP phase of initialization, use of this console can be forced by configuring the guest virtual machine so that it has no usable 3270 consoles. NIP then directs its messages to the guest machine as line mode commands. This is analogous to the stream of messages sent to the Operating System Messages (OSM) window on an HMC by an MVS system running in a logical partition.

Responses to any NIP messages are entered using the CP VINPUT command. Internally this is done when an ISQSEND command is issued to the operator console (OC) of the target system. To ensure that such VINPUT commands are processed correctly, the guest machine must be operating in RUN ON state at this time.

To ensure that RUN ON state is set, a CP SET RUN ON command is sent to all MVS guest machines at the time when the guest machine is started by the PSM.

Once MCS operation is established, important messages requiring operator action are directed to the guest machine. Again, these are analogous to the stream of messages directed to the OSM window of the HMC. Initially, commands cannot be entered to MVS. To do so, it is necessary to enter "Problem Determination Mode". To enter this mode, a VARY CONSOLE(*),ACTIVATE command must be entered. Once this is done:

  • All MVS messages that are displayed are routed to the guest machine
  • Commands may be entered using the CP VINPUT command.

Problem Determination is not generally recommended.

To enter LINUX commands it is normally necessary to log on to LINUX. This requires a user ID and a password. So, to provide for LINUX commands would require the specification of a user ID and a password to ProcOps, with all the attendant difficulties in the area of security. At present the LINUX system is considered IPL COMPLETE when specified messages have appeared. These do not require a user logon.

VM machines may also be guest machines. Third level guest machines are not supported.

VSE machines may also be guest machines.