Alternating Between eMS and OS/VS Under VM/370 When working in a program development environment (rather than a
producticn environment) and unable to test programs directly under CMS, a user can alternate between OS/VS and CMS in a single virtual
machine. Seme advantages of this technique (described in this topic)
are: • Reduced unit record output. Users can examine program output and
compiler listings online, check the results, and resubait the job
without producing any output on the system unit record devices. • Faster turnaround time (generally) than in a batch environment.
Before using this technique, users should be familiar with the eMS editor and CMS file manipulation commands found in the !M/3IQ LOADING CMS INTO A VIRTUAL MACHINE To load CMS into a virtual machine, use the CP IPL command and specify either a saved system name or a device address:
ipl ells -- or --
ipl 190 When CMS responds with a message like this: CMS VERSION 3.0 Enter the CMS commands to create an OS/VS job stream. USING THE CMS EDITOR TO PREPARE JOB STREAMS The fcllowing CMS procedure creates an OS/VS job streaa that can be passed to the OS/VS virtual machine's reader. It shows how to compile a
PL/I program under OS/VS, making the PL/I source file available as a CMS file called PLI27 DECK.
edit pli127 jcl
input
//pli 127 job cps,fred,lIsglevel=1
//cat exec plifc
Iisysin dd *
(null line)
getfile pli127 deck
input
/*
//
(null line)
file
open a CMS file by name
go into input mode enter jcl entries I , return to edit .ode
copy over PL/I source file
go into input mode enter jcl entries , to edit mode write the file to disk Section 4. OS/VS in a Virtual Machine 133

ISSUING SPOOL COMMANDS TO CONTROL UNIT RECORD DEVICES Spool the virtual punch to the virtual .achine:
cp spool punch to *
This command causes subsequent punched output to appear in the user's
own virtual card reader. To submit a job to the OS/VS .achine, punch
the JCL and associated card data. Spool the virtual printer to the virtual card reader:
cp spool printer to *
Instead of routing printed output to the real printer, this co •• and
causes it to appear in the virtual card reader. By using the CBS machine, each print file can then be read, eXamined, and either purged
or printed at the real printer. !Qte: Since a user may find both punch and printer files in the virtual
reader, ccnsider using the spool file class attribute to control which
files are to be processed at anyone time. PUNCHING CMS FILES Use the CMS PUNCH command to transfer the job stream to the virtual card
reader of the OS/VS virtual machine:
punch pli21 job (noheader
By specifying NOHEADER option of the PUNCH command, V8/370 does not punch a CMS READ control card at the beginning of the output deck.
INIZIALIZING OS/VS Lead OS/VS into the virtual machine by issuing this command: cp ipl 250 When an OS/VS reader is started, it reads the job stream that had been previously punched with the punch spooled to the user's own userid.
For example, the OS/VS command: s rdr,OOc starts a reader on virtual device OOC and reads those cards that appear
in the OS/VS reader queue. RELOADING CMS INTO A VIRTUAL MACHINE When the job stream has been processed, reload CftS and use the BE1DC1BD com.and to create a CMS file from the printed output and put it onto a CMS disk. The output can now be examined with the CMS editor or TYPE command. When hardcopy output is needed, the file can be printed via
the CMS PRINT command. When using the REIDCARD co.mand to create a CBS file, do not use a filetype of LISTING. Otherwise, VB/370 assumes the
first character of each line to be a control character, which is not
printed.
134 IBM VM/370 operating Systems in a Virtual Machine