CORBA26 — Changing VSCID prefix to 24 bits

In section 13.6.8 of CORBA 2.4.2 (formal/01/02-01), at the top of page
13-29, it says:

The high-order 20 bits of service-context ID contain a 20-bit vendor
service context codeset ID (VSCID); the low-order 12 bits contain the rest
of the service context ID. A vendor (or group of vendors) who wish to
define a specific set of system exception minor codes should obtain a
unique VSCID from the OMG, and then define a specific set of service
context IDs using the VSCID for the high-order bits.

The VSCID of zero is reserved for use for OMG-defined standard service
context IDs (i.e., service context IDs in the range 0-4095 are reserved as
OMG standard service contexts).

The VSCID-related text was added by the Interop 1.2 RTF as per RTF report
as in document number interop/98-01-04, and revised pages as in document
number interop/98-01-03. However, at about the same time OMG staff
established a convention that OMG should allocate vendors a 24-bit "service
tag", which is in fact the same as a VSCID. Since then, some 47 of these 24
bit service tags have been assigned to various vendors.

At the risk of having the tail wag the dog, I propose we resolve this
conflict by revising these paragraphs in the CORBA spec as follows:

The high-order 24 bits of a service context ID contain a 24-bit vendor
service context codeset ID (VSCID); the low-order 8 bits contain the rest
of the service context ID. A vendor (or group of vendors) who wishes to
define a specific set of system exception minor codes should obtain a
unique VSCID from the OMG, and then define a specific set of service
context IDs using the VSCID for the high-order bits.

The VSCIDs of zero to 15 inclusive (0x000000 to 0x00000f) are reserved for
use for OMG-defined standard service context IDs (i.e., service context
IDs in the range 0-4095 are reserved as OMG standard service contexts).

see below