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subhasis_50
Moderator
Joined: 09 Mar 2005 Posts: 363 Location: Earth
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Hi,
What is the difference between
DD DUMMY
and
DD DSN=NULLFILE |
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vishal_a
New User
Joined: 24 May 2005 Posts: 45 Location: Noida
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hi Subhasis
well actually there is no difference b/w both
we can use sysin dd dummy or nullfile will work as same
no i/o function will be done on dataset
regards
vishal |
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kanak
Moderator
Joined: 12 Mar 2005 Posts: 252 Location: India
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I agree with vishal.There is no difference.
The system bypasses all input/output operations, does not
allocate devices or storage to the data set, and does not perform disposition processing. |
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avalanches
New User
Joined: 10 May 2005 Posts: 28
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Hi,
Does it make any difference in using DUMMY or NULLFILE in the copying? Say initializing an empty file. I've used copying NULLFILE. What about DUMMY?
avalanches |
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SteveConway
New User
Joined: 26 May 2005 Posts: 28 Location: Northern VA, USA
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The previous posters are correct, there is no difference in the processing of DD DUMMY and DD DSN=NULLFILE. There are documented restrictions on the use of NULLFILE, primarily no use as a temp file dsn or a pds name with member specified.
DSN=NULLFILE works as a nice placeholder in a proc for a file that is used intermittently, or has a varying dataset name. You can code all other attributes (DCB, UNIT, SPACE, etc.) and then just override the DSN if you need it. Of course, you can do the same with DD DUMMY; DSN=NULLFILE just lines up neater. :-) |
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xstortion
New User
Joined: 27 May 2005 Posts: 4 Location: NJ, USA
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SteveConway wrote: |
The previous posters are correct, there is no difference in the processing of DD DUMMY and DD DSN=NULLFILE. There are documented restrictions on the use of NULLFILE, primarily no use as a temp file dsn or a pds name with member specified.
DSN=NULLFILE works as a nice placeholder in a proc for a file that is used intermittently, or has a varying dataset name. You can code all other attributes (DCB, UNIT, SPACE, etc.) and then just override the DSN if you need it. Of course, you can do the same with DD DUMMY; DSN=NULLFILE just lines up neater. :-) |
Great answer cosmetic reasons we are so vane |
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enrico-sorichetti
Superior Member
Joined: 14 Mar 2007 Posts: 10872 Location: italy
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Topic cleaned up,
posted a sticky on the same subject |
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