WIMS> CIM> Deprecating (almost) all CurrentXxxx properties in CIM_Printer

WIMS> CIM> Deprecating (almost) all CurrentXxxx properties in CIM_Printer

WIMS> CIM> Deprecating (almost) all CurrentXxxx properties in CIM_Printer

McDonald, Ira imcdonald at sharplabs.com
Tue Aug 9 16:53:07 EDT 2005


Hi Rick,
 
More layers to the onion...
 
IPP operation requests all MUST include the special _operation_ attributes
of 
'attributes-charset' and 'attributes-natural-language' which determine the
Printer's 
choices in operation responses.
 
If the Printer does NOT support the specified 'attributes-charset' value,
then the 
Printer MUST reject the request.  
 
If the Printer does NOT support the specified ''attributes-natural-language'
value, 
then the Printer MUST ACCEPT the request and store the user's attributes
with 
the well-formed (but unknown) language tag and MUST respond using the 
'natural-language-configured' value for any reply text (i.e., the Printer
need not be 
omniscient)
 
So the semantics of 'Xxx-Configured' are more subtle than you describe
below.
 
Cheers,
- Ira
 

Ira McDonald (Musician / Software Architect)
Blue Roof Music / High North Inc
PO Box 221  Grand Marais, MI  49839
phone: +1-906-494-2434
email: imcdonald at sharplabs.com 

-----Original Message-----
From: Richard_Landau at Dell.com [mailto:Richard_Landau at Dell.com]
Sent: Tuesday, August 09, 2005 3:29 PM
To: imcdonald at sharplabs.com; wamwagner at comcast.net; wims at pwg.org
Cc: Winston_Bumpus at Dell.com
Subject: RE: WIMS> CIM> Deprecating (almost) all CurrentXxxx properties in
CIM_Printer



Okay, here's another possibly way-off-center point.  

 

First, apparently I seriously misunderstood the (implied) semantics of the
CurrentCharSet and CurrentNaturalLanguage properties.  I apologize.  I
assumed (always a bad strategy) that they were global items that could in
fact set the default behavior of the management agent.  That is, behavior
similar to prtGeneralLocalization, though that does not permit character set
and language to vary independently.  

 

However, I am now really puzzled about a useful interpretation of the
meaning of "Current" in these cases.  Two questions.  Easy one first.  

 

1.  The printer MOF does not specify any read-write access for properties.
The CIM default for this attribute is False.  Should we attempt to correct
this?  Do we think that these properties might permit read-write access?  Do
we think that any properties in CIM_Printer should permit read-write access?
Such a declaration would be for modeling only; implementations would still
get to permit or forbid write access, authorize it, etc.  

 

2.  Do we think that such properties are global to the management agent or
local to a management session?  If two users simultaneously request
management information in two different languages (using some protocol
mechanism outside these properties), do they see different values of
CurrentNaturalLanguage?  And how current is "Current?"  Does the value
returned describe the language in which this particular response message is
written, or does it refer to a global setting in the printer?

 

I agree with Ira that the printer current values don't change.  I would not
expect any such request to alter the value of CurrentNaturalLanguage.  A
deliberate SET operation might alter the value, but only if the property is
writable; see question 1.  

 

Is there a useful interpretation that we can agree on (and then record in
text in the new MOF), for the semantics of these properties?  Suggestions: 

 

- A CurrentXxxx property describes the behavior of the management agent for
all management request-response exchanges or sessions, unless the request
that initiates the session specifies different behavior.  

 

- A request that specifies different behavior does not change the value of
the CurrentXxxx property.  

 

- The mechanism used by a request to specify different behavior is beyond
the scope of this MOF.  

 

- A CurrentXxxx property may or may not be settable by the end user, as part
of management policy.  The MOF declares that the property as modeled may be
writable.  Implementations may vary in their ability to write the property,
or to authorize writing by consumers, and so forth.  

 

Would such semantics be useful to write down?  The current MOF doesn't
specify the behavior of these properties very clearly.  

 

If this whole topic is not completely off-base, we could just add it to the
list of non-cosmetic questions.  

 

Sorry for the length.  

 

rick

 

 
 
  _____  

From: McDonald, Ira [mailto:imcdonald at sharplabs.com] 
Sent: Monday, August 08, 2005 22:26
To: McDonald, Ira; 'wamwagner at comcast.net'; Landau, Richard; wims at pwg.org
Cc: Bumpus, Winston
Subject: RE: WIMS> CIM> Deprecating (almost) all CurrentXxxx properties in
CIM_Printer


Hi,
 
By the way, the corresponding IPP Printer attributes are called
'charset-configured' and 'natural-language-configured'.  Given that
IPP and the Printer MIB frequently refer to the 'current configuration',
DMTF CIM property names of 'Current...' are fine if we deprecate
all the other non-deterministic 'CurrentXxx' properties.
 
Cheers,
- Ira
 

Ira McDonald (Musician / Software Architect)
Blue Roof Music / High North Inc
PO Box 221  Grand Marais, MI  49839
phone: +1-906-494-2434
email: imcdonald at sharplabs.com 

-----Original Message-----
From: owner-wims at pwg.org [mailto:owner-wims at pwg.org]On Behalf Of McDonald,
Ira
Sent: Monday, August 08, 2005 6:46 PM
To: 'wamwagner at comcast.net'; Richard_Landau at Dell.com; wims at pwg.org
Cc: Winston_Bumpus at Dell.com
Subject: RE: WIMS> CIM> Deprecating (almost) all CurrentXxxx properties in
CIM_Printer


Hi,
 
I agree with the proposal.  
 
However, I strongly DISAGREE with the creation of new DefaultXxx
properties to be used in place of CurrentCharSet/NaturalLanguage.
 
We had this discussion during the development of IPP and concluded
that DefaultXxx has the wrong semantics, because they CANNOT be
overridden by the user.  They are the character set and language
for the values in the Printer Description class of attributes (broadly, 
everything except Status attributes).  A specific user can request
a Notification (for example) in a different charset/language, but the
Printer current values don't change.  This is NOT the semantics
of DefaultXxx on a Printer object.
 
Note that the user MUST specify the charset/language of submitted
string attributes with an IPP Job  - it's a protocol error to omit them.
 
Cheers,
- Ira
 

Ira McDonald (Musician / Software Architect)
Blue Roof Music / High North Inc
PO Box 221  Grand Marais, MI  49839
phone: +1-906-494-2434
email: imcdonald at sharplabs.com 

-----Original Message-----
From: owner-wims at pwg.org [mailto:owner-wims at pwg.org]On Behalf Of
wamwagner at comcast.net
Sent: Monday, August 08, 2005 3:43 PM
To: Richard_Landau at Dell.com; wims at pwg.org
Cc: Winston_Bumpus at Dell.com
Subject: Re: WIMS> CIM> Deprecating (almost) all CurrentXxxx properties in
CIM_Printer


Rick,
 
Makes sense. Perhaps we got carried away in our generalizations and missed
the distinction.
 
I would see no benefit in changing the names of urrentCharSet or
CurrentNaturalLanguage   
 
Bill Wagner
 

-------------- Original message -------------- 


Re: Deprecating (almost) all CurrentXxxx properties in CIM_Printer 

Slight revision to the proposal:  Deprecate all the CurrentXxxx properties
in favor of the corresponding DefaultXxxx properties, except CurrentCharSet
and CurrentNaturalLanguage.  

These last two properties, CharSet and NaturalLanguage, record the character
set and natural language being used for management, not for printing.  They
are properties of the printer controller, not properties of print jobs.
Since they are asynchronous with printing functions, they do not suffer from
the ambiguities of the other CurrentXxxx properties in complex printers.
Also, neither of these properties has a corresponding DefaultXxxx property.
Therefore these two properties must be retained.  

Summary: 

CurrentPaperType                deprecate; use DefaultPaperType instead 
CurrentLanguage         deprecate; use DefaultLanguage 
CurrentMimeType         deprecate; use DefaultMimeType 
CurrentCapabilities             deprecate; use DefaultCapabilities 

CurrentCharSet                  retain 
CurrentNaturalLanguage          retain 

I recall that some exceptions were mentioned, but I think we all mistakenly
referred to CurrentLanguage instead of CurrentCharSet during the discussion.


Addendum to proposal: we could change the *names* of the two remaining
CurrentXxxx properties to DefaultCharSet and DefaultNaturalLanguage and then
be rid of all the CurrentXxxx properties.  (Actual process: add new
properties with identical syntax and semantics but new names, and then
deprecate the old properties.)  Only half kidding.  

Comments, please.  

rick 

------------------------- 
Richard_Landau at dell.com, System Mgt Arch & Stds 
+1-512-728-9023, One Dell Way, RR5-3 Box 8352, Round Rock, TX 78682 


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