FTAM/9000 Programmer's Guide

Chapter 11 439

Document Types and Constraint Sets

Document Types

INTAP-1 Document Semantics

The following semantics are mandatory for INTAP-1 document types.

• An INTAP-1 document consists of one ﬁle access data unit, which

consists only of zero, one, or more records. The order of these records

is signiﬁcant.

• Each record consists of octets of any value from 0 to 255. The meaning

attached to these values is not constrained by the document type.

• There are no size or length limitations imposed by this deﬁnition,

except for those speciﬁed here. Each record is of a length determined

by the number of octets given by the maximum-record-length

parameter. If this parameter is not present, the default is that the

length of the records is unbounded. If the value of the

record-signiﬁcance parameter is variable, or if the parameter is not

present, the length of each record is less than or equal to the length

given in the maximum- record-length parameter. If the value is ﬁxed,

the length of each record is exactly equal to the length given.

NBS-9 Document Type

The NBS-9 document type models directories. Each NBS-9 document

(directory) has only one FADU that contains zero or more data

elements.(Figure 11-8).

Figure 11-8 NBS-9 Document Type Structure

NBS-9 uses the Unstructured constraint set to restrict the ﬁle model,

and therefore uses the Unstructured All access context (Figure 11-9).

Refer to the “Constraint Sets” and “Access Contexts” sections for detailed

information.

FADU

Attributes

Node

Descr.