..-- !
19:22:10
19:22:10 CMS vmfdump
R;
spool rdr cl d
b
The SPOOL RDR CL D command allows the virtual reader to access the
class D dump file. By entering the B (BEGIN) command, the virtual machine user returns to CMS. By entering the veFDUMP command (class C or E), IPCS reads the CP abend dump and creates a CMS dump file, problem report, and symptom summary entry on the 191 A-disk. (For a sample VMFDUMP session, refer to When VMFDUMP processing completes under CMS in the virtual CP system,
terminate the test system by entering real CP mode and initializing CMS. Under CMS, the user can issue the IPCS DUMPSCAN command to look at the
dump taken cf his virtual test system. This dump resides as a dump file
on the user's real 191 A-crisk. Summary
Tc update and test a VM/370 system in a virtual machine, an installation must first have a VM/370 directory entry for a VM/370 virtual machine.
This virtual directory entry need only specify the minimum number of
users sufficient to perform the test. Before initializing this system,
an installaticn should verify that the virtual machine configuration
has: the ccrrect console address, sufficient unit record devices
available a t the correct addresses, and enough disks (either linked or
attached) tc make a reasonable test. Also, the VM/370 virtual machine
can run CMS when it has access to the CMS system residence volume. With few exceFtions, IPL for a VM/370 virtual machine is similar to IPL for a real VM/370 system. Operationally, Ve/370 provides CF ccmmands to disFlay and store into real storage. The VM/370 system in a
virtual machine can also display and store into its own third level
virtual storage. If the virtual machine performs any spooling
oFerations, the virtual VM/310 system is also spooling unless it has
dedicated unit record devices. This double spooling is no problem;
hcwever, there are some special operational considerations.
68 IBM Sjstems kn a Virtual Machine

Section 3. DOS/VS In a Virtual Machine
This section uses the term "DOS/VS" as a generic expression. It
represents any or all of the DOS, DOS/VS, and DOS/VSE system control
programs unless specified otherwise. When loading DOSjVS into a virtual machine running under the
terminal becomes the DOS/VS operator console, and the user is
responsible for entering all the commands and responses normally
required of the operator.
The three basic techniques to use when running DOS/VS in a virtual
machine are: 8 Run DOS/VS in batch mode. The terminal is the operator console, and
other users may submit jobs either through the real system virtual
card reader or from the virtual card punches of other userids. • Use the IPt command to alternate between using DOS/VS and in a
single virtual machine,. Use CMS to prepare a job stream for DOS/VS, use DOS/VS to execute the job stream, and use CMS to check the
output. • tog onto a userid and load DOS/VS. Once it is running, disconnect
from that userid and log onto another userid while the DOS/VS userid
continues working. To check on the status of DOS/VS, disconnect from
the current virtual machine and reconnect the DOS/VS virtual machine.
Before discussing these three techniques in greater detail, the user
must understand how to: • Generate DOS/VS to run in a virtual machine • create VM/370 directory entries for DOS/VS 'virtual machines • Access the DOSjVS system residence volume • Ensure that the proper I/O devices are attached to the DOS/VS virtual
machine • IPt and operate DOS/VS under VM/370 System Generation Recommendations When generating DOS/VS to run in a virtual machine, an installation
should have these primary objectives: • Tc reduce the number of 510 instructions issued by DOS/VS, including
those issued for DOS/VS paging I/O operations • To avoid double CCW translation
To meet these
generates both
objectives, an installation VM/370 and DOS/VS. needs to consider how it Section 3. DOS/VS in a Virtual Machine 69