[Info-vax] Ignorance promenade: On the nature of patching VMS

[Volker Halle]

Am Samstag, 14. Dezember 2013 00:15:25 UTC+1 schrieb Subcommandante XDelta:
> Question:
> Is it possible that certain adustments to deep levels of VMS could not
> be achieved by the issuing of a patch, but would require the complete
> recompilation of the VMS kernel image?

Some changes might require a full recompilation and relink of the OpenVMS operating system components.

Consider a change for a data structure item from WORD to LONGWORD. If this datastructure is being used in multiple components (execlets) of OpenVMS, a full build will be required. In the past, OpenVMS Engineering only induced changes like this in new OpenVMS Versions during minor or even major updates (let's say from V7.x to V8.x).

OpenVMS is not a monolithic operating system, but contains multiple different modular kernel images (called execlets), which are grouped by function (e.g. PAGE_MANAGEMENT.EXE etc.).

Nowadays 'patches' are being distributed as rebuilt execlets or images and NOT as binary patches, which just change a couple of bytes in an image.

Volker.