[Info-vax] New filesystem mentioned

[John Reagan]

On Thursday, May 16, 2019 at 1:43:48 PM UTC-4, Simon Clubley wrote:
> On 2019-05-16, Dave Froble <davef at tsoft-inc.com> wrote:
> > On 5/16/2019 10:04 AM, Bob Koehler wrote:
> >>
> >>     No, DLM is a separate part of the kernel, which is used by and
> >>     required by the XQP and such.
> >
> > Damn, that brings up another question.  Is the DLM part of the kernel? 
> > I don't know the details of the implementation, but, I'd at least hope 
> > it is not.  That would allow it to be used in any modular type of OS. 
> 
> It is a part of the kernel, but only in so far as there is no other place
> to put it in the current VMS design. I can't see anything about the VMS
> DLM which requires direct access to hardware for example.
> 
> It provides services to the rest of the kernel (and to non-kernel
> applications). However, I see no reason why the DLM could not just be
> another task in a microkernel design (for example).
> 
> > And before anyone mentions parts of the kernel might use the DLM, I'd 
> > guess that might happen.  Doesn't mean anything used by the kernel is 
> > part of the kernel.
> >
> 
> In a VMS style monolithic design, it's all part of the kernel.
> 
> This is because, on VMS, the DLM directly provides services to the rest
> of the kernel which means the kernel code needs direct and efficient
> access to the DLM.
> 
> Think of it less about being part of the kernel and more about whether
> the DLM has a clean interface to the rest of the kernel (which would
> make it easier to use elsewhere).
> 
> Going back to Linux, that's one of the advantages of the Linux module
> based architecture. It's all part of the kernel, but there are generally
> reasonably clean interfaces between the various parts of the kernel as
> a result.
> 
> Simon.
> 
> -- 
> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
> Microsoft: Bringing you 1980s technology to a 21st century world



SYSENQDEQ (and a few other modules) are in the LOCKING.EXE execlet.  One of many execlets loaded as part of the OS boot.