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IDCAMS REPRO requires VSAM linear data sets be completely preformatted

Question & Answer


Question

AMS IDCAMS REPRO copy VSAM Linear data set requires source data set to be completely preformatted to the end of its last extent. MSGIDC3350I IDC3350I

Answer

Problem

REPRO does not use the HURBA (high used RBA) value to determine when to stop reading a VSAM linear data set it was requested to copy. It expects to be able to read blocks all the way to the end of the last allocated extent. VSAM Linear data sets do not have a predefined data structure like a VSAM ESDS or VSAM KSDS data set has, and the HURBA field has no meaning apart from whatever the application that creates and/or manages the linear data set defines for it. Generalized utility programs like IDCAMS REPRO cannot know what the application intended to mean by the content of the HURBA field.

If the tasks that create and load the data set or later extend the data set do not preformat all the way to the end of the last allocated extent, REPRO may encounter one of four conditions:

(1) if the ending extents were previously formatted with the same size blocks as the current data set and the current data set is not extended format, REPRO will just read these blocks and copy them to the output. No error will occur during REPRO. The task that later reads or updates the data set may or may not be able to tolerate the junk blocks at the back of the data set.

(2) if the ending extents were previously formatted with the same size blocks as the current data set but the previous and current data sets are both extended format, REPRO may encounter an INCORRECT SUFFIX RCI VALUE when it reads the first remaining junk block beyond the current preformatting. REPRO will issue an error message and stop.

(3) if the originator or extender of the data set preformatted whole tracks or cylinders at a time, and the ending extents were previously formatted with a different BLKSIZE than the current data set, REPRO will encounter an INVALID LENGTH I/O error when it tries to read the first remaining junk block beyond the current preformatting. REPRO will issue an error message and stop.

(4) if the originator or extender of the data set preformatted records without regard to track or cylinder boundaries, the last preformatted track will have one or more data blocks of the correct length from the last preformatting request, but the track may not be filled with the number of blocks expected. REPRO will encounter a MISSING RECORD I/O error when it tries to read the next block beyond the last preformatted block. REPRO will issue an error message and stop.

Resolution

If REPRO encounters one of these errors, use a different utility program to copy the VSAM Linear data set.

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Document Information

Modified date:
03 September 2021

UID

isg3S1001885