page of GC20-1821-3 As Updated April 1, 1981 by TNL GN25-0840 Section 2. VM/370 in a Virtual Machine
This section describes how to update and test a VM/370 system in a
virtual machine. After testing, use the DASD dump restore (DDR) program
to dUmp the virtual CP (VM/370) system to tape. Then, restore that
virtual CP system to the real system residence disk. After performing
these steps, an installation is ready to execute the new version of VM/370 with a minimum amount of real time. VM/370 Directory Definition
Before an installation can test VM/370 in a virtual machine, it must
first have a VM/370 directory entry for a VM/370 virtual machine. The
virtual directory need only specify a minimum number of users that are
sufficient to perform the testing. It is usually beneficial to define
an operator's virtual machine that is large enough and varied enough to
perform all necessary functions. This specification allows most virtual
testing to be done from one userid. It does not require several userids
to dial into this system to accomplish a test.
In the followinq sample directory entry, assume that TESTSYS is the
userid for this virtual machine. TESTSYS has the options and
configuration necessary to define a m1n1mum system for initializing VM/370 in a virtual machine. A sample VM/370 directory entry for TESTSYS would be: USER TESTSYS PASSWORD 512K ACCOUNT NUMBER BIN11 OPTION ECMODE REALTIMER CONSOLE 01F 3215 SPOOL C 2540 READER SPOOL D 2540 PUNCH SPOOL E 1403 LINK CMSSYS 190 190 R MDISK 330 3330 1 15 SYSWRK WR RPASS WPASS MDISK 331 3330 16 20 SYSWRK WR RPASS WPASS The USER statement defines the userid as TESTSYS, the password as PASSWORD, and 512K storage (the minimum amount of storage to load a
virtual VM/370 system).
The OPTION statement specifies the ECMODE and REALTIMER options,
which are required for the virtual machine to operate in extended
control mode and to wait for a timer interruption to continue
processinq.
The CONSOLE and SPOOL statements specify the console and spool
device addresses. These addresses must match the same addresses as
the real machine configuration. If that configuration is not .used
for the virtual system operation, they must match whatever
configuration is specified in the DMKRIO module.
The LINK statement specifies that this virtual machine may operate CMS, althouqh special considerations described later in this
section have to be used to operate eMS. section 2. VM/370 in a Virtual Machine 51

Page of GC20-1821-3 As Updated April 1, 1981 by TNL GN25-0840 The MDISK statements for 330 and 331 define disks for the CP system
residence, paqing, and spooling volumes. This directory entry configuration does not define any other user dIsks, teleprocessing lines, or tape drives. All additionai devices
required for testing VM/370 in a virtual machine can be specified by using the ATTACH, LINK, and DEFINE commands. Virtual Machine Configuration
To run the VM/370 nucleus in a virtual machine, load it onto the
minidisk that represents the virtual system residence volume. Then,
before initializing the system, verify that the virtual machine
configuration has: • The correct console address • sufficient unit record devices available at the correct addresses • Enough disks (either linked or attached) to make a reasonable test When setting up the virtual machine configuration, a user can link to
other user disks so that the VM/370 system can use these disks in its
virtual operation. However, the user must ensure that links to other
disks use the correct addresses and device types.
For example: A real VM/370 system has 2314s defined as 130 to 137
and has 3330s defined as 330 to 337. To avoid operational errors, the
virtual VM/370 system links to user 2314 disks in the range of 130 to
137 and links to user 3330 disks in the range of 330 to 337. If a user
disk is linked to as a 2314 address when it is actually a 3330 or 3340 device, the virtual VM/370 system receives errors when trying to process
that user disk.
DEFINING A CONSOLE FOR VM/370 IN A VIRTUAL MACHINE Since the logon console for a virtual machine operates as a 3215, 3210, or 1052, one of the following two methods can be used to satisfy the
console reqoirements for your VM/370 virtual machine:
1. In the DMKRIO for the second level VM/370 system you are building,
define the console device as DEVTYPE 3215, 3210, or 1052 in the RDEVICE macro (Ex: RDEVICE ADDRESS=01p, DEVTYPE=3215). 2. Another approach is attaching a console-type device to your virtual
machine and using that as your second level VM/370 console. For
example, if your DMKRIO for address 01p defines a DEVTYPE of 3277,
then attach or DIAL a real 3277 to your virtual machine as address 01F to function as your second level VM/370 console. Regardless of which method you choose, you must specify
the CONSOLE directory statement when defining your virtual
operator.
52 IBM VMi370 Operating Systems in a Virtual Mach; 3215 in VM/370