[Info-vax] Creating an open source version of VMS, was: Re: OpenVMS Hobbyist Notification

[Dave Froble]

On 3/10/2020 6:43 PM, Michael Moroney wrote:
> Dave Froble <davef at tsoft-inc.com> writes:
>
>> I haven't studied it from this particular perspective, and without doing
>> so would only be guessing.  But I have to ask, why do you state this.
>> As far as I know the VMS DLM has not much to do with the "kernel" of
>> VMS, supposing there is a definition of that entity.
>
>> Remember, the VMS DLM does no enforcing.  It is strictly a utility that
>> can maintain a database of locks and cooperating processes can be guided
>> by the utility.
>
> The DLM is all kernel mode code and is intertwined with the cluster logic to
> ensure it is consistent across the cluster.  Plus parts of the kernel itself
> use it, as does the file system.
>

Interesting.  Want to ask.  Is that implementation specific?  Just seems 
to me that what it does could be done outside the kernel.  Of course, 
that gets into defining just what is the kernel, right?

Does it need to be in the kernel because it's called from things in the 
kernel?

Or, is it in the kernel to allow system level locks without requiring 
SYSLCK priv?

By "file system" are you referring to RMS, or lower level stuff?

-- 
David Froble                       Tel: 724-529-0450
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