Interested to Buy Any Domain ? << Click Here >> for more details...
Describe the DD statement, its meaning, syntax and keywords?
- 2 Answers
- 9253 Views
- I also Faced
- E-Mail Answers
Answer Posted / sunitha
Ans: The DD statement links the external dataset to the
ddname coded within the executing program. It links the
files within the program code to the filenames known to the
MVS Operating system. The syntax is:
//DDANAME DD DSN=NAME,
// DISP=(NEW,CATLG,DELETE),
// DCB=(DSORG=PS,RECFM=FB,LRECL=80,BLKSIZE=800),
// SPACE=(CYL,(20,5),RLSE),
// UNIT=SYSDA
DSN- Name of the dataset- separated by periods, each name 1
to 8 characters, total 44 chars including periods.
DISP- It specifies the disposition of the dataset.
DISP=(status,normal-disposition,abnormal-disposition)
Status – The statuses NEW,MOD,OLD,SHR are the status of the
dataset at the beginning of the step.
NEW is given to create a new dataset. It is the default if
anything is not coded.
OLD designates an existing dataset with exclusive control.
SHR designates an existing dataset without exclusive
control.
MOD is used to extend the dataset if it exists or to create
a new one if it does not exist.
Normal-disposition- It directs the system on the
disposition of the data set (pass, keep, catlg, uncatlg,
delete) when the step ends normally.
Abnormal-disposition- It directs the system on the
disposition of the data set (keep, catlg, uncatlg, delete)
when the step ends abnormally.
DCB- Physical characteristics of a Data Set are described
by DCB Parameters. These parameters must be coded for newly
created data set as well as for existing Datasets.
• LRECL=n (VALUE IN BYTES)
• RECFM=(F/FB/V/VB/U)
• BLKSIZE= multiple of LRECL
• DSORG=(PS/PO/DA)
PO: specifies a partitioned Organization, DA: specifies a
direct organization.
SPACE=(space units,
(primary,secondary,dir),RLSE,CONTIG,MXIG,ROUND)
space unit - TRK(tracks)/CYL(cylinders)/BLOCKSIZE in bytes.
In our above example it allocates 20 cycles primary and if
required allocates 5 secondary cycles.
RLSE- Request to release the space that is primarily
allocated if unused.
CONTIG- Request for contiguous space.
MXIG- Request for large area of contiguous space.
ROUND- Request for entire cylinder for storage of dataset.
UNIT parameter indicates the information about input or
output device that will be used
by the dataset. It specifies a group name, device type, or
device number that identifies the
device where the file resides. The Format of the UNIT
parameter is UNIT= groupname/
device-type/device number.
VOL parameter is primarily used for tapes. A volume is the
portion of the storage device served by one read/write
mechanism. To request specific volumes, we code
VOL=SER=volume for one volume or VOL=SER=(volume, volume…)
for multiple volumes. Volume serial numbers are one to six
characters.
SYSOUT parameter is used to route the output to a device.
// DDNAME DD SYSOUT=CLASS
| Is This Answer Correct ? | 6 Yes | 1 No |
Post New Answer View All Answers
Brief description of inline procedure of jcl.
I want my job (careerride) to be executed in 1 minute and 2 seconds. How do I do that?
What is the function of job statement in jcl?
What is the use of symbol // in jcl?
How can a fb file convert to vb file using sort program?
Explain the function of the steplib dd statement?
Explain about ISPF/TSO Commands
What is the purpose of disp parameter?
What does a disposition of (MOD,DELETE,DELETE) mean ?
How do you overcome this limitation ?
Is acct parameter mandatory?
1) SORT FIELDS=(20,4,CH,D,10,3,CH,D) OUTREC FIELDS=(7:20,4,C' FUTURE ',20,2,10,3,1Z,1,9,13,7, 24,57,TRAN=LTOU,6X'FF') This example illustrates how a fixed-length input data set can be sorted and reformatted for output. The SORTIN LRECL is 80 bytes. The reformatted output records are fixed length with a record size of 103 bytes. SOLRF (the IBM-supplied default) is in effect, so unless the SORTOUT LRECL is specified or available, it will automatically be set to the reformatted record length of 103. in the above example i have some doubts that a) sort fields=(20,4,CH,D,10,3,CH,D) -what exactly it does and this fields related to output record fields or input record fields b)outrec used to refprmat the records after sorting that means could please reply me as soon as possible Thanks. Venkat
How does the jcl specify the job to os?
How can a jobs execution priority be modified?
what is DD statement is used in JCL?
