[Info-vax] VSI strategy for OpenVMS

[Stephen Hoffman]

On 2021-09-17 00:04:09 +0000, Dave Froble said:

> ...But how about in-house custom developed applications?
> 
> Either one can use what's available, or, one must implement the locking 
> in the application.

Most current server platforms either have an integrated DLM, or have 
one available.

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/high_availability_add-on_overview/ch-dlm 

https://documentation.suse.com/sle-ha/12-SP5/html/SLE-HA-all/cha-ha-storage-dlm.html 


Or the app locking requirements can become database package 
requirements, and whether the chosen database was running locally, or 
was distributed.

When many (most?) existing OpenVMS apps were designed and written, the 
computing world was a very different place.

Else-platform, I've had success with interlocked queues. That approach 
also works well on OpenVMS, as does the OpenVMS DLM of course. The 
OpenVMS DLM APIs are too arcane for my preferences, though.

Existing app code either isn't going to be ported, or isn't going to be 
ported without effort and managerial support.

Refactoring existing and problematic code is more often a possibility 
for existing apps, and one I'd recommend pursuing. Particularly for 
cases when increased code portability can be a consideration.




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