IBM 5280 Distributed Data System - Index of

Data Field Byte GroupsA data field byte group specifies the format of a data field as it is entered via thekeyboard, displayed on the scr~en, and stored in the current record buffer. Thefield starts at the current screen position and current record buffer pointer position.Data fields longer than 1 byte require a length specification in the data field formatgroup as shown in the following diagram:Byte Group 10, I,II ,1 = Last byte of the group.Ii i •I I I I 10 '_' _,_,--.-__Il ' __'-r---' __Ilo Byte Group ID-Must specify one of the following:0000 (picture check)0001 (alphabetic)0010 (numeric)0011 (hexadecimal)0100 (Katakana)0101 (format level 0)1001 (alphabetic only)1010 (numeric only)1011 (digits only)1100 (Katakana only)e Field length minus 1 if the field length is less than 128; otherwise, this bytecontains 7F and the following 2 bytes specify the length minus 1.• If the previous byte is 7F, these bits specify the length minus 1 of the field.A data field with only the following attributes requires only the byte group ID and(if the field is longer than 1 byte) the field length byte(s) to describe the field in thescreen format control string:• Basic field• Format level zero field• Right adjust field• Field exit required field• Manual duplicate field from the previous bufferA data field with additional attributes requires additional bytes to specify fieldattributes, storage duplication areas, or picture specifications.Main Storage Data Areas 107