In section 12.3.7.3 we have this sentence: "The dfdl:lengthUnits may be 'bytes' or 'characters' and it is a schema definition error otherwise. " Does anyone recall why we have this? I have data formats which are bit oriented and there are complex types which would naturally not be a multiple of 8 bytes long, e.g., 1 bit field, 3 bit field, 10 bit field, 6 bit field = 20 bits. I can't think of any reason for this restriction other than to explain how fillByte is used to fill in unused bits. But I think we can say that any unused bits are filled in with bits from the fillByte, and we don't have to be specific about which bits from the fillByte. Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com Please note: Contributions to the DFDL Workgroup's email discussions are subject to the OGF Intellectual Property Policy<http://www.ogf.org/About/abt_policies.php>