OSI/FTAM Programming Guide

NonStop FTAM Programming

HP NonStop OSI/FTAM Programming Guide—528612-001

3-18

FTAM-1 Files

NS-1

∑ ZLEN

+ ((TAG + LEN) * NS) <= 16384

i=0

Encoded-data limit for transfers of FTAM-2 files with FA access

context):

NS-1

∑ ZLEN

+ ((TAG + LEN) * NS) + (8 * ND)<= 16384

i=0

FTAM-1 Files

An FTAM-1 file is an unstructured text file. It consists of a single file-access data unit

(FADU) that includes the entire file.

Writing FTAM-1 Files

To write an FTAM-1 file, you must first open the file, using FTM_OPEN_REQ_ or

FTM_FILE_OPEN_REQ_, with a process-mode (ZFTM-DDL-PROC-MODE)

parameter value of replace or extend, or both. You must use a fadu-id

(ZFTM-DDL-FADU-ID) parameter value of first and a fadu-operation parameter

value of replace or extend, or both, on the FTM_WRITE_REQ_ call. A replace

fadu-operation replaces the data in the file with the data sent during the write

operation, while an extend fadu-operation appends the data sent to the end of the

file.

Actual data is sent with a series of one or more calls to FTM_DATA_REQ_. In each

FTM_DATA_REQ_ 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 exceed16 KB. The data-value parameter consists of one or

more data elements. Each data element uses a value of ZFTM-VAL-DE-TEXT for the

data-element-header type. The actual data is raw text data, and the FTAM initiator

properly encodes this data as ASN.1 strings. (The ASN.1 encoding is transparent to

your application program but can be seen on a trace.)

If multiple data elements are used to send the data, each data element forces the

encoding of a new string to start. Each data element can contain only a single ASN.1

string of no more than 7148 characters.

The initiator allows all three possible values for the string-significance

parameter returned in the contents-type parameter (ZFTM-DDL-CNTNTS-TYPE)

by the FTM_OPEN_CNF_ or FTM_FILE_OPEN_CNF_ procedure call: ZFTM-VAL-

Note. When the NonStop initiator encodes data, the maximum encoded-data header overhead

(TAG + LEN) is always 4 bytes per string. One way to determine the TAG and LEN values for

encoded data from a remote responder is to examine a trace of the NonStop initiator process.