Invalid count fields

The count field is in the format of CCHHR, where CC is cylinder, HH is head (or track) and R is the record. TDMF checks the CCHH portion of the count field. If the cylinder and track address in any source record count field is not equal to its physical location on the volume, then TDMF will normally stop copying data, scan the remainder of the source volume (volume analysis) and terminate the volume pairing with message GTD3550E – Invalid count field.

An invalid count field can occur in a free space area of the volume. In that case, select the FASTCOPY option, which may prevent this error from recurring or run program IEBDG or IEBGENER in order to populate a data set (FASTCOPY will copy unallocated tracks if they share a cylinder with a data set). Either of these programs will re-write the count field, then delete the temporary data set. If the free space area is large, it is recommended to allocate a data set large enough to span the entire area. If there is data in the area, a re-write of the data set will be required.

If the error occurs in the middle of a data set, it could potentially be a broken data set. This does not mean that the data is inaccessible. Frequently, the data can still be accessed. If it is impractical to repair a data set on the source volume that contains invalid count fields, the user can request that TDMF migrate the volume, including the non-standard count fields, after issuing a warning message (see the option specifications that are valid only on the SESSION control statement). Whether the migration was terminated or completed with a warning message, the disk locations of all instances of records with an invalid count field can be reviewed using the TDMF TSO Monitor (Option U.13 – Detected Source Volume I/O Errors).