106 IBM VM/370 Operating Systems in a Virtual Machine
Section 4. OS/VS In a Virtual Machine
This section uses the term "OS/VS" as a generic expression. It
represents any or all of the as, OS/VS1, OS/VS2 SVS, and OS/VS2 MVS system control programs unless specified otherwise. When loading OS/VS into a virtual machine running under VM/310, the
terminal becomes the OS/VS operator console, and the user is responsible
for entering all the commands and responses normally required of the
operator.
The three basic technique s to use when running OS/VS in a virtual
machine are: Batch mode. One user runs as the OS/VS machine (userid OSVS) and
other users (like CMSID1) may submit jobs either through the virtual
card reader, through the system card reader, or via JES remote
stations. Alternating technique. The IPL command is used to alternate between OS/VS and CMS in a single virtual machine. This method requires only
one directory entry, the one for the as/vs user. Because of the
lengthy 1PL process, it is practical only if an installation bas
created an OS/VS saved system. Disconnected user (OS/VS2 only). Because 05/VS2 allows a user to
recall a prior system message, he can log on as an OS/VS2 operator
under the OSVS userid, start up his system, and then disconnect. While the OS/VS2 machine continues to run; the user can log on as a CMS user (CMS1D1) and create and submit job streams and check the
resulting output. To check the progress of the operating system,
disconnect from the CMS machine and reconnect to the OSVS virtual
machine via the LOGON command.
Before discussing these three techniques in greater detail, the
user must understand how to: Generate OS/VS to run in a virtual machine Create VM/310 directory entries for OS/VS virtual machines Access the OS/VS system residence volume Ensure that the proper I/O devices are attached to the as/vs virtual
machine 1PL and operate as/vs under VM/310 System Generation Recommendations When generating OS/VS to run in a virtual machine, an installation
should have these primary objectives: To have all commonly used transient routines made residence in
storage To run all jobs (if possible) as V=R jobs
Section 4. OS/VS in a Virtual Machine 101
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