OSI/FTAM Programming Guide

NonStop FTAM Programming
HP NonStop OSI/FTAM Programming Guide—528612-001
3-16
Data-Value Parameter
Where NS = number of data elements
ZLEN
i
= length in bytes of the ith character string
PAD = pad byte following string; if string length is even,
PAD = 0; otherwise, PAD = 1; for the purposes of
these calculations, PAD = 1
ND = number of node descriptors
FSL = FADU structure length (size of ZFTM-DDL-DE-FADU data
structure, or 50 bytes)
50 = internal initiator header overhead
16 = maximum data-value data header overhead
26 = maximum data-value element-header overhead per data
element
Data-value limit for most transfers (excludes FTAM-2 files with
FA access context):
NS-1
∑ ZLEN
i
+ ((26 + PAD) * NS) + 16 <= 25600 - 50
i=0
Data-value limit for transfers of FTAM-2 files with FA access
context:
NS-1
∑ ZLEN
i
+(FSL * ND)+(26 * ND)+((26+PAD) * NS)+16 <= 25600 - 50
i=0
If the application receives a provider abort with a diagnostic indicating an unspecific
initiator error and a Further Details field indicating smaller PDU or larger MSL
needed, the size of the encoded data from the remote responder might be too large
for the initiator to properly decode. You need either to increase the size of the
maximum string-length or have the responder send smaller PDUs. You can increase
the size of the maximum-string-length parameter only if the string-significance
value is not significant. Otherwise, the responder must send smaller PDUs.
Sending Data to a Remote Responder. When you pass data from the application to
the initiator, the following formulas for calculating data-value size apply. The
formulas refer to the structure of information submitted in FTM_DATA_REQ_ calls; for
an explanation of the structure for each FTAM document type, refer to the subsections
on the individual document types that follow. As shown in the equation, the
data-value limit is 24 KB.
Two formulas are used: one for calculating the data-value limit on transfers of
FTAM-1, FTAM-2 files with UA access context, and FTAM-3 files, and one for
calculating the limit on transfers of FTAM-2 files with an FA access context: