H06.12 Software Installation and Upgrade Guide

after fallback. When the files are accessed for the first time after the fallback, they are
converted to Format 1 and show their actual size.
If the DP2 fallback SPR is not installed, you cannot access any Format 2 files using either OSS or
Enscribe on a pre-H06.05 system, even if the files are smaller than 2 GB.
DP2 has a dependency on DSAP/DCOM. If you install the DP2 fallback SPR (T9053AQM), you
must also install T9543H01^ABH as described under “DSAP/DCOM”.
DSAP/DCOM
Migration
The DSAPDDL file is changed in the product revision of DSAP/DCOM delivered in the H06.06
and later RVUs (T9543H01^ABH), resulting in changes to the work file layout. You must use the
DSAPDDL file distributed with T9543H01^ABH when running ENFORM queries on the work
file created using this SPR. The DSAPDDL file for T9543H01^ABH contains these changes to the
directory-record structure:
• The field named fifth is changed from type binary unsigned to type binary 32 unsigned.
• These fields are added to the end of the structure:
— Field flab2_flags1 of type binary unsigned identifies OSS files larger than 2 GB.
— Field ext-0-fsu of type binary unsigned contains the extent size of large OSS files for
extent number 0.
— Field ext-1-128-fsu of type binary unsigned contains the extent size of large OSS
files for extent number 1-128.
Fallback
The H06.06 and later versions of DSAP/DCOM (T9543H01^ABH) are large OSS file safe, but
pre-H06.06 versions are not. If you fall back from H06.06 or later to an earlier RVU, HP
recommends that you install T9543H01^ABH during the fallback.
NOTE: An application that is “large file safe” causes no data loss or corruption when it
encounters an OSS file larger than 2 GB. It may not necessarily have the capability to process
OSS files larger than 2 GB, but it has the appropriate logic to handle errors or warnings detected
during file manipulation operations and fail gracefully.
Backup and Restore 2 Fallback
OSS files larger than 2 GB that have been backed up cannot be restored to a pre-H06.06 system.
Install the Backup and Restore 2 fallback SPR T0744H01^AAA to restore files smaller than 2 GB
in the following situations:
• If you have a backup tape with a mix of OSS files smaller than 2 GB and larger than 2 GB.
You can restore the smaller files to an H06.05 file set by first installing T0744H01^AAA.
• If you have created backup tapes on H06.12 and you are falling back to H06.05.
Files larger than 2 GB are skipped. T0744H01^AAA does not support pre-H06.05 RVUs.
Guardian Compatibility Issue
OSS support for files greater than 2 GB has resulted on a compatibility issue for applications
using Enscribe APIs to access Guardian files created by OSS APIs.
Prior to the H06.06 RVU, Guardian files created by OSS APIs were always created as Format 1
with a 175 MB maximum size. As of H06.06, Guardian files created by the open() and creat()
functions are Format 1 with an approximate 2 GB maximum size, and Guardian files created by
the open64() and creat64() functions are Format 2 with an approximate 26 GB maximum
size.
OSS Large Files 45