Re: Assumptions we'll rely on for MDC2

[Torre Wenaus <wenaus@bnl.gov>]

Thanks for checking. I reviewed this and sent a reply to Arie; it looks good to
me.
  -Torre

Doug Olson wrote:
> 
> Torre & Dave,
> 
> I just want to make sure that you saw Arie's note about
> MDC2 assumptions, that you understand them,
> and that you accept them.  And if you don't accept them,
> that you speak up.
> 
> Thanks,
> Doug
> 
> > -----Original Message-----
> > From: Arie Shoshani [mailto:arie@math.lbl.gov]
> > Sent: Friday, October 30, 1998 12:45 AM
> > To: gcdev@sseos.lbl.gov
> > Subject: Assumptions we'll rely on for MDC2
> >
> >
> > We discussed the various requirements for the Storage Manager
> > components for MDC2, and want to make explicit the assumptions we
> > are relying on.  This is mainly to verufy that we all agree on
> > these assumptions.
> >
> > 1)  Each event header will contain information about the event
> > components.  Thus, in response to a multi-component request from an
> > EI, it is sufficient for the Storage Manager to return only the
> > event_oids list.  The user code will get the OIDs for each
> > component from the event header.
> >
> > Note: as explained in my last message the response to a request
> > from an EI has the form:
> >
> > [file_c(i), file_c(j), ...]: {list of event_oids},
> >
> > where file_c(i) is the ID of a file for component i that contains
> > all the event components in the {list of event_oids}.  Similarly,
> > for file_c(j), etc.
> >
> > We call [file_c(i), file_c(j), ...] a file bundle.  There are
> > multiple file bundles for each multi-component query, where some
> > files may appear in multiple file bundles.
> >
> > 2)  A response to a multi-component request will be made only after
> > all the component files were cached.
> >
> > 3)  For component files that are not stored in Objectivity, there
> > will be an empty directory in Objectivity.  Thus, each
> > non-objectivity file will have a file_oid, and its names can be
> > gotten from the objectivity directory, just as for Objectivity
> > files.
> >
> > 4)  Files can be stored in multiple directories.  Thus, for each
> > PFTP the file location (path) will be determined dynamically.
> >
> > 5)  The cache (using multiple disks) will be managed by a
> > multi-disk file manager (such as veratose).  Thus, the entire cache
> > will be viewed as a single cache by the Storage manager.
> >
> > Comments?
> >
> > Arie.
> >
> >
> >
> >

-- Torre Wenaus, BNL     wenaus@bnl.gov    516-344-4755  Fax 516-344-4206 --
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