The format of the 3-byte date fields is yydddF, which represents a packed decimal number in which y represents year, d represents day, and F represents the sign. Examples of RACF® date values are X'98111C' and X'94099D'.

The format of the 4-byte date fields should be yyyymmdd, which represents a packed decimal number in which y represents year, m represents month, and d represents day. Examples of RACF date values are X'19980421' and X'19940409'.

RACF might use any of the following values for null dates: X'FFFFFF', X'00000D', X'00000C', and X'000000' for 3-byte addresses, and X'FFFFFFFF', X'0000000D', X'0000000C', and X'00000000' for 4-byte addresses. However, you should always set null dates to either X'00000F' for 3-byte addresses and X'0000000F' for 4-byte addresses.