User`s guide

4: FMP Link Configuration Options
DC 900-1339H 75
fit in one buffer. Data packing also helps move data from Freeway to the client more
efficiently over the Ethernet.
The default for this option is enabled. To disable this option using the DLI configuration
file, use the
dataPacking parameter; for example, dataPacking = “no”. See Table 5–1 on
page 104.
Note
Earlier versions of the BSCDEMO interactive program might dis-
play this option as “space compression”; however, you can still use
this option to turn data packing on or off. For more information,
refer to the BSCDEMO User’s Guide.
4.9.1 How Data Packing Works
When data packing is enabled, the FMP software starts packing incoming messages
when it detects that the message buffers are not being read by the client fast enough; i.e.,
unread buffers start collecting on the Freeway ICP board. When this happens, the FMP
software attempts to put any newly received data into the previous waiting message
buffer. This happens only if the previous message buffer has enough free space to hold
the new data. If it does, FMP copies the new data into the previous buffer, placing it
behind the data already in the buffer. The data size of the previous buffer is updated to
reflect the number of bytes added to the buffer. Finally, the ICP buffer that contained
the new data is released to the ICP free pool to be reused.
Note
Data packing takes place only when the client cannot read the
incoming data fast enough. If the client application is keeping up
with the flow of incoming data, it might never see a packed data
buffer, even though the data packing option is enabled.