OSI/FTAM Programming Guide

NonStop FTAM Programming
HP NonStop OSI/FTAM Programming Guide—528612-001
3-23
FTAM-2 Files
FTM_WRITE_REQ_ procedure call. You can write only to the end of an FTAM-2 file.
You can replace the contents of an FTAM-2 file by first erasing the file and then writing
to the end of the file.
However, you must first have negotiated the file-access service class to erase the file.
For more information about erasing a file, see the example for the
FTM_ERASE_REQ_ procedure call in the OSI/FTAM Programming Reference Manual.
Actual data is sent with a series of one or more calls to FTM_DATA_REQ_. In each
FTM_DATA_REQ_ procedure call, the data is sent by way of the data-value
parameter, which when encoded must be no greater than 16 KB. This is because a
one-to-one mapping exists between P-DATA requests and FTM_DATA_REQ_
procedure calls, and according to NIST FTAM Phase 2 agreements, P-DATA carrying
encoded FTAM PDUs or data elements cannot exceed 16 KB. The data-value
parameter consists of two or more data elements. Two types of data elements can be
used: node-descriptor data elements and text data elements. Each text data element is
preceded by a node-descriptor data element, whether you are writing to a single or
multiple nodes.
Figure 3-8 shows the structure of the data-value parameter for FTAM-2 files when
you write to a single node. ZAPS-DDL-DATA-HDR indicates the number of data
elements in the data-value parameter, and ZAPS-DDL-DATA-ELEMENT-HDR
indicates the length and type of data in the data element.
Figure 3-9 on page 3-24 shows the structure of the data-value parameter for
FTAM-2 files when you write to multiple nodes. For each node, each text data element
of type ZFTM-VAL-DE-TEXT is preceded by a node-descriptor data element of type
ZFTM-VAL-DE-FADU.
This pattern is repeated for one or more nodes.
Figure 3-8. FTAM-2 Data-Value Parameter for Writing Single Node
VST0308.vsd
ZAPS-DDL-DATA-HDR
ZAPS-DDL-DATA-ELEMENT-HDR
(type = ZFTM-VAL-DE-FADU)
ZFTM-DDL-DE-FADU
ZAPS-DDL-DATA-ELEMENT-HDR
(type = ZFTM-VAL-DE-FADU)
Text Data element