If a virtual .achine runs one operating system most of the time, a user
can have that system automatically loaded each time he logs on. Use the IPL statement to identify the operating system to VM/370, such as by the following:
ipl 350 The virtual address 350 contains the system to
operating system has been
specify:
ipl DOSVS represents the address of the device that
be loaded. or, if the virtual machine's
"saved" using the CP SAVESYS command), Where DOSVS is the name under which the system was saved. !Qte: For the V"/370 system operator to automatically log onto a virtual
machine (by using the class A or B AUTOLOG command), the virtual machine directory entry must contain an IPL control statement.
The CONSOLE central statement has no unique considerations for running
an system in a virtual machine.
The MDISK centrol statement has no unique considerations for running an
oFerating system in a virtual machine.
The SPOOL centrol statement has no unique considerations for running an system in a virtual machine. Use the DEDICATE control statement to provide a virtual machine with a
corresponding real device. The virtual machine has sole use of the
dedicated device. A device such as a magnetic tape driYe can be used by
only one virtual machine at a time; therefore, specify it in a directory
entry with a DEDICATE statement.
Example: The directory specifies:
DEDICATE 181 281
This statement allows the operating system to access the device at real
address 281 via a virtual address of 181.
Section 1. General Considerations 43
In most cases, spooling represents the most efficient
way of handling the unit record input and output of many virtual
machines. However, special cases may justify the dedication of a real
unit record device to a single virtual machine. One special case is when the virtual machine's operating system does
its own spooling, such as POWER/VS under DOS/VS or JES under OS/VS. To
eliminate double sFooling of printer output, include a DEDICATE
statement in the virtual machine's directory entry, such as:
DEDICATE OOE 002 This statement causes VM/370 to pass all virtual printer OOE output
directly to the real printer at 002. Another case where a user may want a unit record device dedicated to
his virtual machine would be if the virtual machine produced a
sufficient volume of output to keep the device busy. Users can also have the system operator dynamically dedicate a unit
record device to their virtual machine. First, send the system operator
the message:
#cp msg operator pIs attach punch at ooa
If a punch is free at OOd, the operator issues the command:
attach OOd to userid as OOd When the device is attached, VM/370 sends a confirmation message to PUN OOD ATTACHED When the device is no lenger needed, issue the command: Icp detach OOd Devices: The DEDICATE statement can be used to place a
device that --VM/370 does not support into a virtual machine's
configuraticn. To dedicate a device, the device must: Be physically connected to the System/370 Be supported by the virtual machine's operating system Not violate
restriction any of the restrictions contained in
section of the Fer examFle: A directory entry can include the statement:
DEDICATE 007 012 the VM/370 where real address 012 could represent a 2671 Paper Tape Reader that is
part of the System/370 on which VM/370 is running. If the operating
system was generated with a 2671 defined at address 007, handles
the device and CCW address translation associated with reading from the
device. The operating system in the virtual machine is responsible for
error recovery and error recording procedures. QU IBM VM/370 Operating Systems in a Virtual Machine
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