Preparing Applications for OpenVMS x86-64

In a previous installment, I wrote about the general process of preparing for the integration of OpenVMS x86-64 into general use. While the first production-ready release of OpenVMS x86-64 is still in the future, there are many steps which can be taken now. This preparation will make the arrival of OpenVMS x86-64 Version 9.2 far easier when the time comes.

OpenVMS x86-64 can be run within a virtual machine environment. Supported virtual machine environments presently include Oracle's VirtualBox and KVM. There is hope that VMware will be supported by the time OpenVMS x86-64 is available for production.

Virtual machine support means that OpenVMS x86-64 can be run on a moderately-sized notebook, desktop, or cloud computing instance, whichever is best for your circumstances. Check the list of supported virtual machine environments and determine which is appropriate in your local circumstances, as some organizations may have standards in this regard.

The first step is to ensure that you are running the latest version of OpenVMS on your Alpha or Integrity (Version 8.42L2 if you have an EV5 or later Alpha processor), together with current, up-to-date compilers.

The next step is to ensure that it is possible to cleanly rebuild your locally-developed applications from source files. If shareable libraries are used, they must be included in the rebuild process. If object files or libraries are used, they must also be rebuilt. The goal of this step is to ensure that all of the source files needed are available and compilable. Use this process to eliminate manual steps; since all steps in the process will need to be repeated, this is an opportunity to put all the steps into a script or scripts for future use.

Once your local applications have been compiled and linked, run comprehensive tests to make sure that the freshly-rebuilt applications actually function as intended. I will write more about this in a future installment. For now, suffice it to say that this step is critical, as I noted during the lead-up to Itanium (see The Third Porting: Applying Past Lessons to the Alpha/Itanium Transition. One does not want to chase problems during the transition that existed previously on Alpha/Itanium.

Many, if not most, applications will be ready for building for x86-64 at this point. At this point, it is worth auditing the source code for areas that may be architecture-dependent:

References to processor-specific conditional code (VAX, Alpha, Itanium; a subject for a future column)
Exception-handling
Stack manipulation
VAX-format floating point (on VAX and Alpha).

If nothing is found, the code is likely ready to be compiled for OpenVMS x86-64.

References

R. Gezelter (2002) The Third Porting: Applying Past Lessons to the Alpha/Itanium Transition HP Enterprise Technology Symposium, St. Louis, Missouri. Retrieved from http://www.rlgsc.com/hpets/2002/1224.html on June 20, 2020

URLs for referencing this entry

Long:	http://www.rlgsc.com/blog/openvms-consultant/preparing-for-openvms-x86-64.html
Short:	http://rlgsc.com/r/20200622.html