Re: Persistence for Ada-9X?

[sxc@itd.dsto.gov.au (Stephen Crawley)]

In article Czo@ois.com, beckwb@ois.com (R. William Beckwith) writes:
>  posting for Jon Anthony (jsa@gensym.com)
>  ----------------------------------------
>
>R. William Beckwith (beckwb@ois.com) wrote:
>: My view of persistance involves (at least) these four elements:
>: ... Various steps ...
>
>Note that OMG has officially blessed the Persistence Services part of
>the Common Object Services Specification.  So, the *what* that needs to
>be done is done and furthermore, it is completely specified in IDL.  It isn't
>just CORBA that makes an Ada/IDL mapping important, its the fact that a
>whole plethora of services are (or have already been) standardized via IDL
>and are being implemented (check out Tivoli Systems for instance...)

I didn't see your (?) message to which Jon Anthony is replying.  (A lot
of "comp.lang.ada" messages never reach us at DSTO ...)

I would infer from what Jon is saying that CORBA Persistence Services 
provide "copying" style persistence; i.e. where saving and restoring
a data structure generates a new copy in the application program's 
address space.  

Many people in the DBPL research community would argue that
this style of persistence is inferior to "orthogonal" persistence
in which making an object persistent does not alter it's identity
properties (or any other properties apart from it's lifetime).  
Languages that provide orthogonal persistence include PS-Algol and
Napier88.

A few days ago, I presented a paper entitled "Orthogonal Persistence
and Ada" at TRI-Ada '94 which discusses the linguistic problems of
supporting O.P. in Ada83 and Ada9X.  While Michael Oudshoorn (my
coauthor) and I concluded that full O.P. is not feasible in Ada83/9X,
we are currently thinking about a more limitted form of O.P. that could 
be implemented using GNAT / GCC as a starting point.  

I will provide a URL for the TRI-Ada '94 paper in a week or so (when
I can find a publicly visible resting place for it.)

Could anyone who is interested in Persistence in Ada9X please
send me a brief email?

-- Steve

email: <sxc@itd.dsto.gov.au> or <stephen.crawley@dsto.defence.gov.au>