Stimmen - 0, Durchschnittliche Bewertung: 0
(
)
)
|
Dieses Gerät hat auch andere Anweisungen:
PC Desktops - HP Integrity NonStop H-Series (16.73 mb)
PC Desktops - HP Integrity NonStop H-Series (957.56 kb)
PC Desktops - HP Integrity NonStop H-Series (881.66 kb)
PC Desktops - HP Integrity NonStop H-Series (965.62 kb)
PC Desktops - HP Integrity NonStop H-Series (676.93 kb)
PC Desktops - HP Integrity NonStop H-Series (393.72 kb)
PC Desktops - HP Integrity NonStop H-Series (776.57 kb)
Anleitung Zusammenfassung
DataLoader/MX Components
DataLoader/MX File System
DataLoader/MX File System
To provide important loading features that are not directly supplied by the Enscribe file
system, DataLoader/MX layers its own file system on top of the Guardian file system.
The DataLoader/MX file system is designed to support DataLoader/MX, so some of the
capabilities in the underlying Guardian file system are not used. For example,
DataLoader/MX processes files sequentially, so it does not use random I/O.
The DataLoader/MX file system includes these features for sequential file processing:
• Concatenated files. DataLoader/MX enables you to point to data files that in turn
point to other data files. As a result, you can load from very large data files or build
extremely large data file sets, consisting of many files. Using the INDIRECT option
for input and output, you can go beyond the size limitation for single files.
• Full files. DataLoader/MX follows a specific strategy for file-full situations. When it
encounters an error 43 or 45 on a file, DataLoader/MX writes a request to its
stderr process for the name of another file to use. The new file name can have
the standard interpretations and modifiers. Because there is no time-out, you can
take as much time as necessary to specify another file. You can also choose not to
specify another file, causing DataLoader/MX to terminate. If you specify a file and
that file also fills up, DataLoader/MX prompts again for a subsequent file or files.
• File creation. If you enter the name of a file that does not exist, DataLoader/MX
creates it for you. If the specified file name is an OSS name, it is created as an odd
unstructured file. The TEXT interpretation is not added by default. If the specified
file name is a Guardian name, the file is created as an EDIT file. If you do not want
your output file to be a text file type, create a file of the type that you want at
another OSS shell prompt, and then give the file name to DataLoader/MX.
For information about treating a set of output files as a unit, see the description of
the INDIRECT interpretation on page 4-7.
• Unstructured files. Unstructured files are considered by the DataLoader/MX file
system to be simply a string of bytes. Any structure inside an unstructured file must
be provided by the application. Unstructured files are important in the loading
process because they can use bulk I/O, the ability to read or write in any multiple of
2 KB up to 56 KB chunks. The use of bulk I/O reduces the cost per byte of I/O,
which is best for I/O intensive applications like loading. However, bulk I/O has
these restrictions:
° Secondary partitions are not supported. Bulk I/O treats the primary partition as
the only partition. If an unstructured file with secondary partitions is given to
DataLoader/MX, it terminates with an error giving the name of the offending file
and the number of secondary partitions it has. This restriction does not limit the
ability of DataLoader/MX to process a large amount of unstructured data
sequentially, because any number of (unpartitioned) unstructured files can be
concatenated using the INDIRECT interpretation.
DataLoader/MX Reference Manual—543544-001
2 -3
...Dieses Handbuch ist für folgende Modelle:
PC Desktops - HP Integrity NonStop J-Series (565.62 kb)
PC Desktops - HP NonStop L-Series (565.62 kb)