Record Formats

When the EXTENDED attribute is declared for a data set in DASDL, the system automatically allocates two additional words at the beginning of each record: the lock word or Transtamp, and the Record Serial Number (RSN). The fields correspond to the words as follows:

Word

Allocated by DASDL

0

Transtamp field

1

RSN field

2 through n

User fields

Fixed Part of the Record

The fixed part of the record is arranged in the following order:

  • Count item, if any.

  • Record type, if a variable-format record.

  • Population items in the order in which they are declared.

  • System-created Boolean values which indicate whether STORED OPTIONALLY items are present on disk.

  • Data items and group items in the order in which they are declared.

  • Links items, sets, subsets, and data sets in the order in which they are declared. Embedded data sets, sets, and subsets (other than standard and compact data sets) take 12 digits of space in the master record. Embedded standard and compact data sets take no space in the master record, but they must be referenced by at least one set.

  • Regardless of the position of the filler item declaration, the filler in the record is located after all data items and group items, and before all control items.

Variable-Format Part of the Record

The variable-format part of the record is organized in the following order:

  • Data items and group items in the order in which they are declared.

  • Link items in the order in which they are declared.

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