Introduction
There is a potential
issue with the use of the Large File Data Sets (LFDS) feature of TurboIMAGE.
This feature exists in TurboIMAGE versions C.10.03 through C.10.09. We know of
no customers who are currently experiencing this issue and the potential for
being impacted by it is extremely small.
Hewlett-Packard have taken the following steps to address this potential
issue:
This LFDS web site details the steps which you should implement if you have
TurboIMAGE versions C.10.03 through C.10.09 installed on any of your HPe3000
systems.
You can determine the version of TurboIMAGE installed on your system in one
of two ways:
- RUN QUERY.PUB.SYS and issue the "VERSION" command which will display a list
of TurboIMAGE component versions. The overall version will appear as
TurboIMAGE Overall VUF:
HP30391C.10.05 TurboIMAGE/XL
- RUN DBDRIVER.PUB.SYS,VUF which will also display a list of TurboIMAGE component
versions. The overall version will appear as
Procedures:
HP30391C.10.05 TurboIMAGE/XL
If your version of TurboImage is less than C.10.03 it does not contain the LFDS features
therefore no action is necessary.
Using an LFDS capable database created on C.10.xx could result in data
corruption or abnormal termination of dataset access when records were written
to the dataset at a 4GB boundary.
If a dataset was LFDS capable (i.e. greater than 4GB or able to grow larger
than 4GB with either MDX or DDX) but no records have been written at or past the
4GB boundary then no difficulties would be experienced and the integrity of the
database would not have been compromised.
Who Is At Risk?
If TurboIMAGE version C.10.xx is installed on your system you may
be at risk but only if you have created an extremely large dataset or you have
created a dataset using either Master Dataset Expansion (MDX) or Detail Dataset
Expansion (DDX) that could eventually grow to beyond 4GB in size.
If your schema files specify CONTROL JUMBO you will always get
"Jumbo" datasets no matter how large your datasets may need to be. The only way
for LFDS features to be enabled for a database are if this CONTROL specification
is not used and datasets in the database are built greater than 4GB or
could grow to be greater than 4GB using either MDX or DDX.
It is important to note that the LFDS feature should not be confused with
LARGESET as this option forces the use of record numbers instead of record
names, and allows larger JUMBO datasets. There are no known issues with the
LARGESET CONTROL option.
What Should Be Done?
Hewlett-Packard has developed patch TIXMXW7 that will disable the LFDS features
of TurboIMAGE C.10.xx. This patch also includes an LFDS detection tool that will
scan all databases on your system checking to see which, if any, are using the LFDS feature.
If you are using TurboIMAGE C.10.xx you should install the TIXMXW7 patch (or the latest patch that supersedes it) at your earliest convenience.
What is LFDS?
The Large File Dataset or LFDS feature of TurboIMAGE was meant to allow a dataset to exceed 4
gigabytes
in size in a single file (a gigabyte is 1,073,741,824 bytes).
Prior to the LFDS feature the only way to have a dataset that exceeded 4
gigabytes was to use the "Jumbo" feature. This used a CONTROL statement in the
schema file to tell DBSCHEMA to create the dataset using 'chunks' which are
files in the POSIX name space. For example, a database called "MYDB" with a
jumbo dataset might have dataset files named "MYDB01.001", "MYDB01.002" etc.
Jumbo datasets did not permit the use of either Master Dataset Expansion (MDX)
or Detail Dataset Expansion (DDX). These are features that allow datasets to be
created smaller with the ability to expand as their capacity increases.
Using the LFDS feature allowed the dataset to exist within a single file and
would also allow both MDX and DDX to be used.
How Was The LFDS Feature Delivered?
The Large File Datasets feature was originally
included with the C.10.03 release of TurboIMAGE. This release of TurboIMAGE was included
with the base MPE/iX 7.5 (C.75.00).
MPE/iX 6.5 (C.65.00) and MPE/iX 7.0 (C.70.00) did not include the LFDS feature.
However, this feature could be acquired by installation of a limited distribution patch TIXMXK2. As a result it is
highly unlikely that any MPE/iX 6.5 or MPE/iX 7.0 sites have installed an
affected version of TurboIMAGE.
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