AIX Version 4.3 Differences Guide

• Debugging purposes. These trace points are only enabled when the driver is
compiled with -DDEBUG turned on, and therefore, the driver can contain as
many of these trace points as desired.
The main goals for having trace points in a CDLI device driver are to be able to
monitor drivers for errors and to track packets as they move through the driver. To
this end, it is important that trace points be placed at the beginning and end of
each main routine that does processing on packets. Also, it is important to try and
trace the flow of buffers (for example, mbufs) as they flow through the system.
There should also be trace points placed at each point where an error could
occur.
The device driver also has trace points to support the netpmon program
(component cmdperft). There are generally five trace points:
WQUE An output packet has been queued for transmission.
WEND The output of a packet is complete.
RDAT An input packet has been received by the device driver.
RNOT An input packet has been given to the demuxer.
REND The demuxer has returned.
All CDLI drivers must register for a trace hook IDs.
NOTE: CDLI device drivers may register for more than one trace hook ID. In the
case of multiple trace hook IDs, one could be used for transmit, one for receive,
and another for errors.
7.13.3 Error Logging
The device driver will do error logging when the following situations occur:
• An error on PIO operations
• A hardware failure on the device
• An error on DMA operations
• Network errors
• Other device specific errors
7.14 Open Network Computing (ONC+)
The ONC+ technology has been licensed from SunSoft and is being included
within AIX to meet customer requirements. This technology contains many
different functional components; the main ones being: NFS Version 3, NIS+,
CacheFS, TIRPC, and AutoFS. Not all of these components are included with this
release of AIX. NFS V3 was introduced in AIX Version 4.2.1. CacheFS was
introduced in AIX Version 4.3.0, and AutoFS was included in AIX 4.3.1.
7.14.1 CacheFS
CacheFS is a local disk cache mechanism for NFS clients. It provides the ability
for an NFS client to cache file system data on its local disk, thereby avoiding use
of the network and NFS server when the data is accessed and is not in physical
memory. This improves NFS server performance and scalability by reducing
182 AIX Version 4.3 Differences Guide