GT.M V5.3-004 adds major new functionality and platform support.

• Support for z/OS on the IBM eServer zSeries computing platform.  GT.M programs now run on mainframes using the zFS file system with a high degree of portability from and to other POSIX environments.  Refer to the GT.M on IBM eServer zSeries z/OS Technical Bulletin for details. 
• Database encryption.  GT.M on selected platforms can encrypt data in database and journal files.  Encryption protects against unauthorized access to data by an unauthorized process which is able to access disk files, that is, encryption protects data at rest (DAR) to help improve security in cloud based application deployment, as well as making it easier for sites to comply with data protection standards such as PCI and HIPAA.  A plug-in architecture facilitates use of your preferred encryption software.  Refer to the GT.M Database Encryption Technical Bulletin for details. 
• Alias variables.  Intended to provide an underlying technology for implementing an object layer, alias variables provide a layer of abstraction between the name of a local variable and an array analogous to that provided by M pass by reference in subroutine invocations.  Multiple local variables can be aliases, and a SET or KILL to one acts as a SET or KILL to all.  Alias container variables provide a way of storing a reference to a data-space in an M sparse array, which protects the associated array even when it’s not accessible through any current name.  Refer to the GT.M Alias Variables Technical Bulletin for details. 

This database file size limit has been increased from 128M to 224M blocks.  So using the popular 8KBthe largest database file that can be created is 1,792GB.  Of course, since a complete database can consist of an arbitrary number database files, the size of a complete database is truly enormous.

There are performance enhancements, among others, especially for applications that use Transaction Processing.  Compilation is faster and uses less memory.  MUPIP LOAD is much faster in UTF-8 mode.  There are of course smaller enhancements, remedied misfeatures, and bug fixes.  Details are in the GT.M V5.3-004 Release Notes.