OSI/FTAM Programming Guide

ISO FTAM Concepts
HP NonStop OSI/FTAM Programming Guide—528612-001
2-32
NBS-9 Documents
of variable, fixed, or not-significant. The value of variable indicates that all strings in
the file are of variable length up to the value of the maximum-string-length
parameter. The value of fixed indicates that all strings in the file are equal to the
maximum-string-length parameter in length. The value of not significant
indicates that the boundaries of strings in the file are not necessarily preserved in a
data transfer.
String length and string-significance are concepts independent of the FADU structure.
A node can theoretically consist of any number of strings, and the means for
representing the significance of a string within a file will vary with the implementation.
On the NonStop system, each string is stored as a record.
Section 3, NonStop FTAM Programming provides much more information on FTAM
document types and their corresponding file types on the NonStop system.
Table 2-10 shows which of the parameters just described apply to each FTAM
document type.
.
NBS-9 Documents
NIST (formerly the National Bureau of Standards, or NBS) defined the NBS-9
document as a read-only directory. An NBS-9 document consists of only a root node
with a data unit (which can be empty), but no node name. The data unit contains zero,
one, or more data elements of type FileDirectoryEntry, which is a sequence of file
attributes. Each FileDirectoryEntry data element corresponds to an actual file in the
directory.
The only action allowed with NBS-9 files is read, with a FADU identity of first.
Only one access-context value, unstructured all-data units (UA), can be used with
NBS-9 files. Therefore, only file-contents data elements are transferred.
As NBS-9 files are read-only, your application cannot write them (which would require
the replace action on the destination file storage system). NBS-9 files provide the
ability to read a file-system directory.
Table 2-10. FTAM Document Types, Universal-Class-Number, Maximum-String-
Length, and String-Significance
FTAM Document Type
FTAM Parameter FTAM-1 FTAM-2 FTAM-3
Universal-class-number X X
Maximum-string-length X X X
String-significance X X X
Note. These document type parameters apply only to the three NonStop FTAM document
types described above, and not to NBS-9 documents.