• The IPL control statements that a user wants to supply, such as:
set
dpd
assgn sysrec,x'250'
set rf=yes
log
Assume for the purposes of this example that: (1) these files have file identificaticns of SUPER JCL and START JCL, and (2) in these files
are all the statements needed to control DOS/VS IPL. The CMS editor can also be used to prepare the job stream selected
for execution. For example: To assemble an assembler language source and make the source file available as a disk file, edit the
file and insert the DOS/VS job control statements into the file.
The file DOSTEST JCL might contain: II JOB TESTl II OPTION NODECK II EXEC (assembler language source statements) 1* 1& Although this job stream contains only
necessary to assemble the job, it can
necessary tc link-edit the output module, on: the job control statements
also include the statements
catalog the program, and so ISSUING SPOOL COMMANDS TO CONTROL UNIT RECORD DEVICES Before sending a job to the DOSIVS virtual machine, check the unit
record devices: • Close and purge the card reader, to make sure no files are left over
from a previous job:
spocl reader nocont
close reader
purge reader all • Close and purge the card punch, and spool it to the card reader: punch nocont
close punch purge
spocl punch to * When using the card reader to 1PL DOS/VS, spool the punch least the first two files must be separate spool files. Section 3. DOSIVS in a Virtual Machine 95

• 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