Resolution:
Prior to OSB R5.0 external syntax N fields were written in Zoned Decimal format with a sign in the zone of last byte of X'C' or X'D' for positive and negative numbers respectively.  At OSB R5.0 and above the sign in the last zone byte will be X'F' or x'D' for positive and negative numbers respectively.

Environment:
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o OSB systems on z/OS

Symptoms:
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Prior to OSB R5.0 zoned decimal numbers were not readable as the sign in the zone of the last byte a non numeric character. At R5.0 and above positive numbers will be readable as a sign nibble of F is used for positive numbers. Negative numbers will still not be readable due to a zone nibble of D.

Cause:
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This is a deliberate change is to bring the z/OS OSB product in line with the Open System OSB product. Both behaviours are valid according to the z/OS Principals of Operation manual.

Resolution:
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Users must code their non-OSB applications to treat a sign nibble of F as a positive number as per z/OS Principals of Operation.

EXP table field with xsyn=N does not return positive sign, x'C',at R5.0 and above.Instead it returns x'F', which is also a positive sign.