• Spool the virtual printer to the card reader:
spool printer to *
For DOS/VS SYSLST output to print on the system printer, omit this SPOOL command. A user can also spool the printer file to a different
class, such as L. This action ensures that the printer is closed
before the user is ready to IPL CMS and that DOS/VS does not read
the printer file from the reader: spocl printer to * class 1 PUNCHING CMS FILES Use the CMS PUNCH command to punch spcoled to the virtual card reader.
files used above, enter: punch super jcl (noheader
punch start jcl (noheader punch dostest jcl (noheader
the card files. The files are
For example, to punch the three
The NOHEADER cption must be used to suppress punching a C8S READ control
card, which is punched by default when using the PUNCH command. INITIALIZING DOS/VS When the DOS/VS syste. residence volume is attached to the virtual
machine, use the IPL command to load DOS/VS: ipl 250 After waiting a few moments, the DISPLAY command to see if the system is in a wait state. After determining that the system is in a
wait state, enter an attention interruption:
! ! CP display psw PSW = 030EOOO 00000000 ready OOc begin
After this BEGIN command returns control to the virtual machine, the
file SUPER JCL is read from the card reader, and the IFL procedure
ccntinues. Again, the user must wait for the system to enter a wait
state and ready the reader:
! ! CP display psw PSi = 030EOOOO 00012800 ready OOc begin
96 IBM VM/37G operating Systems in a Virtual 8achine

When the IPL procedure is complete, such messages as these appear: 01521 PAGE DATA SET EXTENT LOW HIGH
327 0 250 11 01201 IPL COMPLETE FOR DOS/VS REL xx.x ECLEVEL=nn BG 1COOA ATTN. OOC BG
As a practical matter, an installation may want to create a DOS/VS saved system at this point so that the future loading of DOS/VS would
avoid these preliminary steps. Refer to the .§I§iem for infcrmation on creating saved systems. SIGNALING DOS/VS TO READ THE JOB STREAM When DOS/VS has been loaded and the message BG indicates that it is
waiting for communication, enter a null line. This action causes DOS/VS to begin reading the next spool reader file, which is the one
that contains the job control statements, and in this example, the
assembler language source program.
If the LOG command is issued during the IPL procedure r all of the
job control statements that are read are displayed on the terminal as
they are executed. If the RDE option is in effect for DOS/VS Release 34 (or earlier),
respond to these messages before the job is executed:
1I89A IPL REASON CODE =
1I91A SUB-SYSTEM ID = When the job sent from the punch to the card reader has been read r this
message appears, followed by a time stamp: EOJ TEST1
The time stamp could look like this:
DATE 02/19/76,CLOCK 20/19/28 DURATION 00/07/48 Additional messages from the background partition can also appear, such
as:
BG 1COOA ATTN. OOC BG When punching more than one job and the spool files for rema1n1ng jobs
are still in the card reader, enter another null line to signal DOS/VS to read from the reader. Section 3. DOS/VS in a Virtual Machine 91