The two nonprivileged instructions are: CS (compare and swap) CDS (compare double and swap) VM/370 allows the compare instructions (CS and CDS) to execute normally; th·at is, it does not - sillula te them when t·he reai machine is equipped with the appropriate hardware feature. However, when MVS is run under VM/370 on a machine that does not have these instructions installed, VM/370 simulates them. Summary When loading OS/VS into a virtual machine, the terminal becomes the
as/Vs oFerator console, and the virtual machine user becomes the
operator responsible for entering all commands and responses. The three
basic techniques for runningOS/VS in a virtual machine are: batch aode, alternating between as/vs and CMS in a single virtual machine, and
(forOS/VS2 users only) running OS/VS2 disconnected.
Before using one of these techniques, an installationmust understand
how to:• Generate OS/VS to run in a virtual aachine • Create VK/370 directory entries for as/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• IPt and operate OS/VS under VK/370 The primary objectives when generating as/vs to run in a virtual machine should be to have all commonly used transient routines resident
in storage and to run all jobsV=R if possible. To meet these
objectives, an installation needs to consider how it generates bothVM/370 and OS/VS. (asjVs can also be generated under VM/370.) To contrel OS/VS in a virtual maChine, use as/vs operator commands
to hold and release queues and jobs, and to start initiators or define
partitions.Users can observe the progress of the command's execution
by fellowing theOS/VS messages. Also, additional operator commands and
centre 1 stateaentsmust be entered at the console before running jobs on
theOS/VS virtual machine. OS/VS virtual machine users can use the CMS editor and the EXEC facility to prepare jobs for execution in an as/vs virtual machine.
They can also useeMS commands to develop and test programs on CMS disks.
138IBM VM/370 operating Systems in a Virtual Machine
as/Vs oFerator console, and the virtual machine user becomes the
operator responsible for entering all commands and responses. The three
basic techniques for running
(for
Before using one of these techniques, an installation
how to:
machine
in storage and to run all jobs
objectives, an installation needs to consider how it generates both
to hold and release queues and jobs, and to start initiators or define
partitions.
by fellowing the
centre 1 stateaents
the
They can also use
138