RE: Aggregate Attributes

["Joel M. Halpern" <joel@longsys.com>]

I don't know if this is Randy's problem, but I have noticed that 
non-divisibility is being used by some people interchangeably with 
atomicity.  I think that these are two different concepts.

1) Non-divisibility to me means that if I define an attribute group A bade 
up of attributes A1, A2, & A3 I can not declare that attriubte group B 
contains attribute group A, but only contains A1 and A2.  If I want to 
include A, I include A1, A2, and A3.  This is a sensible and useful property.
2) Atomicity would mean that if I have something defined as having 
attribute group A, any time I wanted to reference it (get, set, ...) I 
would have to reference the entire group and not its parts.  This seems to 
me to be a very different, much more protocol oriented concept.  It also 
happens to be one I disagree with strongly.  If by atomicity we mean 
something different from this, then I would appreciate some betrer 
definitions of terms.

Yours,
Joel M. Halpern

At 03:54 PM 9/20/01 -0700, Durham, David wrote:
>Hi Randy,
>I'm not sure I follow why you can't reconcile these two. 4.1.27 says
>non-divisible grouping, 4.1.28 says you can compose larger constructs out of
>them. It says nothing about dividing up their attributes. Where's the
>conflict?
>
>C={a,b}
>D={C,e}={a,b,e}
>
>-Dave
>
> > -----Original Message-----
> > From: rpresuhn-lists@dorothy.bmc.com
> >
> >
> > Hi -
> >
> > > From: Frank Strauss <strauss@ibr.cs.tu-bs.de>
> > ..
> > > The descriptions of attribute groups and containment now say:
> > >
> > > 4.1.27:
> > >    Description: An attribute group is a non-divisible, extensible
> > >       grouping of attributes that are meaningful together.
> > It can be
> > >       reused as the type of attributes in other attribute
> > groups (see
> > >       also Section 4.1.28).  This is similar to `structs' in C or
> > >       `classes' in Java.
> > >
> > > 4.1.28:
> > >    Description: SMIng must provide support for the creation of new
> > >       attribute groups from attributes of more basic types and
> > >       potentially other attribute groups.
> > ..
> >
> > These appear to be in conflict.  I can't reconcile the "non-divisble"
> > in 4.1.27 with the process of composition described in 4.1.28.
> >
> > (Also, it still bugs me that this definition of "attribute group"
> > bears little resemblance to the concept as defined in X.720, which
> > defines "attribute group" as "a group of attributes which have
> > been given a single identifier for ease of access.")
> >
> >  ------------------------------------------------------
> >  Randy Presuhn          BMC Software, Inc.  1-3141
> >  randy_presuhn@bmc.com  2141 North First Street
> >  Tel: +1 408 546-1006   San José, California 95131  USA
> >  ------------------------------------------------------
> >  My opinions and BMC's are independent variables.
> >  ------------------------------------------------------
> >
> >