RE: Assumptions we'll rely on for MDC2

["Doug Olson" <dlolson@lbl.gov>]

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.
> 
> 
> 
>