Communicator e3000 MPE/iX Release 6.5 Express 2 (Software Release C.65.02) (30216-90322)

62 Chapter4
Increases in Limits
Large Size Datasets in TurboIMAGE/iX
Entrynumber format vs. Jumbos vs. MPE Large Files
It has to be noted that this enhancement per se will not make use of the large file feature
of MPE release 6.5. Creating a database in entrynumber format or migrating a database to
entrynumber format just allows the datasets to grow beyond 80 GB (which is the current
limit). There is no harm in keeping the database in entrynumber or entryname format, if
the dataset size is less than 80 GB. Also, there is no impact if some databases are kept in
entrynumber format and others in entryname format in the same system. However, as of
version C.09.02 of IMAGE, the only mechanism to have a dataset size greater than 4 GB, is
to use 'Jumbo' feature. This will be the case, till IMAGE makes use of the large file feature
of MPE.
Conclusion
In summary, this release
• Enhances TurboIMAGE/iX to support large dataset sizes beyond 80 GB (currently up to 10
TB, if the maximum entrysize of 2378 halfwords is used, and the dataset contains the
maximum number of records 2**31-1).
• Provides a way of migrating existing databases, if large size dataset support is required.
• Ensures that existing databases and applications continue to work as today.