Technical data

SunOS 5.5 STREAMS Modules bufmod(7M)
When buffering is enabled by issuing an SBIOCSCHUNK ioctl to set the chunk size to a
non zero value, bufmod sends a SETOPTS message to adjust the stream head high and
low water marks to accommodate the chunked messages.
When buffering is disabled by setting the chunk size to zero, message truncation can have
a significant influence on data traffic at the stream head and therefore the stream head
high and low water marks are adjusted to new values appropriate for the smaller trun-
cated message sizes.
BUGS bufmod does not defend itself againstallocation failures, so that it is possible, although
very unlikely,for the stream head to use inappropriate high and low water marks after
the chunk size or snapshot length have changed.
modified 27 Jul 1992 7M-51