[Info-vax] CRTL and RMS vs SSIO

[Stephen Hoffman]

On 2021-10-06 02:06:29 +0000, Greg Tinkler said:

> I notice that SSIO (beta) in included in an up coming V9.1 field test.  
> So I read up on the issues it is trying to solve.
> 
> One concerning thing was to have CRTL (via SSIO) access directly to 
> XFC.  From an architectural point of view this is wrong at so many 
> levels,...

Off the top, some of the various existing stuff that breaks layering on 
OpenVMS includes HBVS volume shadowing, MOUNT, and byte-range locking.

IP as a layered product is broken layering.

The C select() call is a fine mess of mis-layering.

The XQP design is mis-layering.

There are other examples.

There are examples of breaking layering to advantage, such as ZFS 
else-platform.

All discussions of layering and esthetics aside, I presume the primary 
purpose of the SSIO project is to permit porting PostgreSQL to OpenVMS, 
posthaste.



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