Technical data

System Management Release Notes
5.10 OpenVMS Registry
the snapshot files which may be difficult to repair. Third, by periodically
exporting the database, creating a new database, and importing the saved
export file; you are effectively compacting the database and thereby keeping
it smaller and more efficient.
It should also be noted that in previous versions of OpenVMS, the EXPORT
command may have failed to complete the operation under some conditions. You
could normally recover simply by re-invoking the REG$CP image and retrying
the operation until it was successful.
In addition, in previous versions of OpenVMS, the IMPORT command failed to
properly import keys with classnames or links. The only way to recover from this
was to modify the keys to add in the classnames or links, or to recreate the keys
in question.
5.11 Performance—Comparing Application Performance Data
V7.3
The OpenVMS virtual I/O cache (VIOC) and the extended file cache (XFC) are
file-oriented disk caches that can help to reduce I/O bottlenecks and improve
performance. (Note that the XFC appears on Alpha systems beginning with
Version 7.3.) Cache operation is transparent to application software. Frequently
used file data can be cached in memory so that the file data can be used to satisfy
I/O requests directly from memory rather than from disk.
Prior to Version 7.0, when an I/O was avoided because the data was returned
from the cache, the direct I/O (DIO) count for the process was not incremented
because the process did not actually perform an I/O operation to a device.
Starting with Version 7.0, a change was made to cause all I/O requests—even
those I/Os that were actually avoided because of data being returned from the
cache—to be counted as direct I/Os.
This change can be a potential cause for confusion when you are comparing
application performance data on different versions of OpenVMS. Applications
running on Version 7.0 and later may appear to be performing more I/O than
they did when run on earlier versions, even though the actual amount of I/O to
the disk remains the same.
5.12 Point-to-Point Utility Documentation
V7.3
The Point-to-Point utility (PPPD) initiates and manages a Point-to-Point Protocol
(PPP) network connection and its link parameters from an OpenVMS Alpha host
system.
A chapter in the OpenVMS System Management Utilities Reference Manual:
M–Z describes the PPPD commands with their parameters and qualifiers, which
support PPP connections.
5.13 Queue Manager—Long Boot Times
V7.3
At certain instances the queue journal file (SYS$QUEUE_
MANAGER.QMAN$JOURNAL) may grow to a large size (over 500,000 blocks),
especially if there is a very large volume of queue activity. This may cause either
a long boot time or the display of an error message, QMAN-E-NODISKSPACE , in the
System Management Release Notes 5–27