[Info-vax] New filesystem mentioned

[johnwallace4 at yahoo.co.uk]

On Thursday, 16 May 2019 08:35:57 UTC+1, Chris Scheers  wrote:
> Dave Froble wrote:
> > On 5/15/2019 8:34 AM, Simon Clubley wrote:
> >> On 2019-05-14, Grant Taylor <gtaylor at tnetconsulting.net> wrote:
> >>> On 5/14/19 9:36 AM, Dave Froble wrote:
> >>>> Perhaps because no other OS (well, almost all) has a DLM.  At least 
> >>>> that
> >>>> I'm aware of.
> >>>
> >>> Linux has a distributed lock manager in kernel for the GFS2 file system.
> >>>
> >>
> >> For those of you who has never looked at it, reading the libdlm
> >> documentation is very interesting. Here's the dlm_lock() call:
> >>
> >> https://linux.die.net/man/3/dlm_lock
> >>
> >> And no, you are not looking at a VMS documentation page by mistake.
> >> That really is a Linux man page. :-)
> >>
> >> BTW, here's the overview page for libdlm:
> >>
> >> https://linux.die.net/man/3/libdlm
> >>
> >> Simon.
> >>
> > 
> > Interesting.  To me, there are too many similar names and such.  Even 
> > AST delivery.  That looks like an implementation of some of the VMS DLM 
> > on another OS.  It's always good to copy the best.
> > 
> > Similar to some etching used on a VAX chip, back in the day.  The 
> > Russians copied the chip, including the etching, which said something 
> > about "copying the best".  I don't remember the details.  It was good 
> > for some laughs at a DECUS symposium.
> > 
> > Locking isn't all that hard to design and implement.  John Santos 
> > duplicated the RSTS locking for ROSS/V.  He also helped me implement a 
> > locking tool way back then.  When I designed my DAS database, the VMS 
> > DLM was available, and, it was cluster aware.  Now, that part is really 
> > impressive.  Saw no reason to again re-invent a wheel.
> > 
> > Now, if I was told that the people implemented that tool on Linux didn't 
> > copy from VMS, I'd highly doubt the statement.
> 
> They may not have copied from VMS directly.
> 
> I vaguely remember an announcement a long time back that a company had 
> "acquired" the DLM technology that was used in VMS.
> 
> (I quote, because I don't remember the details.  Given, bought, found, ???)
> 
> I think it was Oracle, but I don't remember for sure.
> 
> This may have made its way into Linux.
> 
> -- 
> -----------------------------------------------------------------------
> Chris Scheers, Applied Synergy, Inc.
> 
> Voice: 817-237-3360            Internet: chris at applied-synergy.com
>    Fax: 817-237-3074

Readers *might* find this CNET article from last decade sheds some light
on how a VMS-like DLM spread further than you might expect:
https://www.cnet.com/news/the-many-lives-of-advfs/

See also: TruCluster Server, RealApplicationClusters (Oracle RAC), etc.

It's a bigger picture than I have time to describe at the moment,
but it may prompt input from others who remember it better than I
do.