Page of GC20-1821-3 As Updated April 1, 1981 by TNL GN25-0840 For DOS/VS Release 34 (or earlier), the individual standard label
cylinders should be placed at the end of the system residence volume
(following the normal standard label cylinder). To support unique
standard label cylinders, modify DOS/VS as follows: • The communication region in each DOS/VS virtual machine must point to
the appropriate label cylinder for each user. Do this by modifying
the IPL communication routines. • Bypass the procedure $JOBCTLA. This procedure updates the
communication region pointer to the normal standard label cylinder at
the end of each job. , • Bypass the label cylinder reset code in the $$BSYSWR procedure. I $$BSYSWR resets the normal standard label pointer whenever a condense I function (CONDS) of the MAINT program is requested. As an I alternative, never condense a library in any virtual machine using a I non-standard label cylinder.
Using Virtual Unit Record Devices When using DOS/VS in a virtual machine,
unit record devices, which are normally
en try:
a user must have the following
defined in the VM/370 directory • A victual card reader, from which DOS/VS reads the job input stream. • A victual printer, which receives all the SYSLST output generated
during DOS/VS operation. • A victual card punch, which receives SYSPCH output generated during DOS/VS operation.
Depending upon how DOS/VS was generated, a user may need to determine
a virtual device address. For example: If DOS/VS expects a 3211
printer at address 002 and no printer is at this address in the virtual
machine configuration, define one with the CP DEFINE command:
define 3211 002 When using CMS to prepare jobs for a DOS/VS virtual machine, use
the virtual card punch to spool jobs to the DOS/VS virtual machine.
Before using DOS/VS, find out (from the programmer at the
installation responsible for generating and maintaining DOS/VS) what
are the virtual device requirements.
A user can control virtual unit record devices with the CP SPOOL command. However, printed or punched output need not have to be printed
or punched. For example: When using a technique for alternating between
operatinq systems, a user can spool the virtual printer to the card
reader, as follows:
spool printer to *
This command reads printed output onto a CMS disk so that it can be
examined. Also, use the SPOOL command to change the output spooling
class of the virtual machine's spooled printer or punch files.
84 IBM VM/370 o?erating Systems in a Virtual Machine

DEFINING THE OPERATOR'S CONSOLE During DOS/VS system generation, an address is specified for the oFerator's ccnsole= The user's terminal must also be at this address. Usually, DOS/VS expects the operator's console to be at real address 01F. The device has to be generated as a 3215, 3210, or 1052 console.
However, when using DOS/VS in a virtual machine, any terminal type can
be used as the virtual operator's console.
To find out the virtual machine's terminal address, enter this
command:
query console
If the resFcnse indicates that the terminal is not at 01F but at another
address, such as 009 (which is a standard console address),
enter this command:
define 009 as 01f This command allows the terminal to now function as the operator's
console for both DOS/VS and CMS. Preparing Jobs for a DOS/VS Virtual Machine
There are several ways to prepare a job stream for a DOS/VS virtual
machine: • Prepare a deck of punched cards that contains such information as DOS/VS job control statements and input files. Place a CP ID
statement at the beginning of this deck to indicate the userid of the DOS/VS virtual machine; for example:
ID DOSVUSER Then put the cards in the real system card reader. Based on the
use rid specified on the ID card, VM/370 directs the spool file to the
virtual card reader of the DOS/VS virtual machine, which in this case
is being run on the userid DOSVUSER. • Use CMS to create a disk file containing card images identical to the
cards submitted in a real card reader for DOS/VS. Use the CP SFCCL command to spool the virtual card punch to the card reader of the DOS/VS virtual machine and use the CMS PUNCH command to punch the
card images. In the CMS environment, issue:
spool punch to dosvuser
punch dosjob jcl (noheader Use the NOHEADER option of the PUNCH command to suppress punching a CMS READ control card at the beginning of the card deck.
A job stream spooled to DOS/VS by either of these methods remains in
the card reader of the DOS/VS virtual machine until the user causes DOS/VS to begin reading the job stream from its card reader. Spooling the card file can be done before or after initializing DOS/iS or a t any time while the system is active.
section 3. DOS/VS in a Virtual Machine 85