Subject: PMP> RE: IPP> RE: Media Names, case sensitivity

From: "Hastings, Tom N" <[email-masked]>
Date: Tue, 3 Apr 2001 15:34:38 -0700

So how about the following short, clear, concise conformance statement:

Letters in the names defined in this standard use all lower case.  For
interoperability and implementation efficiency, this standard STRONGLY
RECOMMENDS that other referencing standards also use these names in their
all-lower-case form.  

Comments?

Tom

-----Original Message-----
From: Bergman, Ron [mailto:[email-masked]]
Sent: Tuesday, April 03, 2001 14:22
To: 'Harry Lewis'; Hastings, Tom N
Cc: [email-masked]'; [email-masked]; pmp (E-mail);
[email-masked]'; Bergman, Ron; [email-masked]'
Subject: RE: IPP> RE: Media Names, case sensitivity

I agree with Harry.  This document really should not mandate case
sensitivity.  We should simply STRONGLY RECOMMEND lower case.  
Adding more paragraphs does nothing.  All a document that references
this standard needs to do is state "...names per IEEE ISTO PWG 5100.5,
with all names represented using upper case characters."  Unless we
hire Brinks or the Mafia, we cannot force anyone to fully comply.

As Harry said "a short, clear, concise definition"

	Ron

-----Original Message-----
From: Harry Lewis [mailto:[email-masked]]
Sent: Tuesday, April 03, 2001 2:05 PM
To: Hastings, Tom N
Cc: [email-masked]'; [email-masked]; pmp (E-mail); [email-masked]';
Bergman, Ron; [email-masked]'
Subject: RE: IPP> RE: Media Names, case sensitivity

If we want to insist on all lower case then why don't we just say so? I 
just want a short, clear, concise definition.
---------------------------------------------- 
Harry Lewis 
IBM Printing Systems 
---------------------------------------------- 

"Hastings, Tom N" <[email-masked]>
Sent by: [email-masked]
04/03/2001 02:50 PM

        To:     "Bergman, Ron" <[email-masked]>, "'Harry
Lewis'" 
<[email-masked]>
        cc:     "[email-masked]'" <[email-masked]>, [email-masked], "pmp
(E-mail)" 
<[email-masked]>, "[email-masked]'" <[email-masked]>, "[email-masked]'" 
<[email-masked]>, "pmp (E-mail)" <[email-masked]>
        Subject:        RE: IPP> RE: Media Names, case sensitivity

I'd like to express an objection to Harry's proposal for case
insensitiveness in media names.  As I understand case insensitiveness, any
mixture of upper and lower case characters match and must be treated as
equivalent.  Therefore, a recipient (client or Printer) has to convert to
some internal case convention before comparing for a match.  But to be 
user
friendly, such a recipient (Printer) should remember the case that was
originally sent by the client, so that the user when querying the same
attributes subsequently, sees the original case that the user submitted. 
To
me, such implementation does not lead to "interoperability and
implementation efficiency", but just the opposite.

That is why IPP specifically uses all lower case for keyword attribute
values and so does UPnP.  So do other protocols that use IPP semantics.
Even  prtInputMediaType object in the Printer MIB (RFC 1759) has all lower
case values defined.  Now that we have general agreement in the current
print protocols to use all lower case, why not at least RECOMMEND all 
lower
case be used by such referencing standards?  So I'd like to see something
like Harry's approach, but RECOMMEND that values be all lower case.  After
all, keywords are really tokens for programs, not people.  Having to deal
with case conversion in a protocol for no benefit, seems a waste.

Also once keyword names are all lower case, then they are also "case
sensitive", allowing for more efficient matching.  So if a client supplies 
a
keyword name with some uppercase characters, they won't match the 
supported
values that the Printer has (since they are all lower case).

BTW, IPP does RECOMMEND case insensitive matching for attributes with 
'name'
data type, but the 'keyword' data type MUST be all lower case (and hence
case sensitive matching for keywords is simpler and correct).

Also I'd like to see the statement moved from the Media Size Self 
Describing
Names section to the general conformance section for all three kinds of
names, as suggested by Ron.

So using Harry's approach, but making it apply for Media Type Names, Media
Color Names, and Media Size Self Describing Names, the following two
paragraphs would be added to section 6 Conformance Requirements:

" Letters in the names defined in this standard use all lower case.  For
interoperability and implementation efficiency, this standard RECOMMENDS
that other referencing standards also use these names in their
all-lower-case form.  Then case sensitive matching can be used.  However,
other referencing standards MAY allow substitution of any lower case 
letter
with its corresponding uppercase letter in the names defined in this
standard.  Such standards MUST require that such substituted letters be
treated as equivalent to their corresponding lower case letters, i.e.,
case-insensitive matching. 

For example, if a referencing standard allows uppercase letters in the 
names
defined in this standard, then the following examples MUST be equivalent:
'na-letter.8500-11000', 'NA-LETTER.8500-11000, 'NA-Letter.8500-11000',
'Na-LeTtEr.8500-11000'. "

Comments?

Tom

-----Original Message-----
From: Bergman, Ron [mailto:[email-masked]]
Sent: Tuesday, April 03, 2001 07:54
To: 'Harry Lewis'; Hastings, Tom N
Cc: [email-masked]'; [email-masked]; pmp (E-mail); Bergman, Ron;
[email-masked]'; [email-masked]'
Subject: RE: IPP> RE: Media Names, case sensitivity

Harry,

I like your proposal and unless others express an objection
will add this to the document.

                 Ron

-----Original Message-----
From: Harry Lewis [mailto:[email-masked]]
Sent: Tuesday, April 03, 2001 7:32 AM
To: Hastings, Tom N
Cc: [email-masked]'; [email-masked]; pmp (E-mail); Bergman, Ron;
[email-masked]'
Subject: Re: IPP> RE: Media Names, case sensitivity

I suggest something more compact like - 

"Media Size Self Describing Names are not case sensitive. As a convention, 

they
are presented here using lower case characters. Other referencing 
standards
may impose case sensitive rules across their own interface. For 
interoperability and implementation
efficiency, imposing case sensitivity is not recommended. "
---------------------------------------------- 
Harry Lewis 
IBM Printing Systems 
---------------------------------------------- 

-----Original Message-----
From: Bergman, Ron [mailto:[email-masked]]
Sent: Monday, April 02, 2001 18:16
To: 'Hastings, Tom N'; Bergman, Ron
Cc: [email-masked]'; [email-masked]'; [email-masked]'; pmp (E-mail)
Subject: RE: Media Names, case sensitivity

Tom,

See my comments below

                 Ron

-----Original Message-----
From: Hastings, Tom N [mailto:[email-masked]]
Sent: Monday, April 02, 2001 4:52 PM
To: Bergman, Ron
Cc: [email-masked]'; [email-masked]'; [email-masked]'; pmp (E-mail)
Subject: RE: Media Names, case sensitivity

Ron,

About case sensitivity in names in the Media standard: 

Draft 0.3 had:

Media Size Self Describing Names are not case sensitive but will always be
presented in this standard using lower case characters.

What I changed it to was:

While Media Size Self Describing Names are presented in this standard 
using
lower case characters, other standards that use these names, MUST indicate
the case sensitivity for their conformance.  Such other standards MAY:

a)               also require only lower case as in this standard
b)               allow lower, upper case, and mixed case to be used with 
the same
meaning as the names in this standard, i.e., case insensitive matching
c)               require all uppercase letters to be used with the same 
meaning as
the corresponding names in this standard.

Discussion:

The important question is what interface is the media standard defining
conformance requirements for?  I had assumed that the media standard was 
NOT
trying to define an interface that the Printer would implement or that a
client would implement, but rather was giving a set of names and their
semantics that other standards would reference.

RB >> I agree!

  It would be up to these
other standards to say whether or not case was important.  For example, 
IPP
says that keywords are all lower case, so that both client and Printer can
count on having all lower case and not having to worry about case
conversion.  Other protocol, such as the Printer MIB use of MediaType and
UPnP use of MediaType and MediaSize would have to say whether or not case
was important.  We might want the Media standard to RECOMMEND that these
other standards only use all lower case.  That would lower the burden on a
Printer that is supporting, say, IPP, UPnP, and Printer MIB, if all three
standards REQUIRED that the values be all lower case.

RB >> If IPP requires lower case and UpNP requires upper case, then
responses
from the printer that contain media names have to be converted for one
client 
or the other, depending upon the printer table.  Existing IPP printers 
most 
likely have the table implemented as lower case.  So, I would recommend 
that

to be compatible we should really REQUIRE lower case.  Then it would be 
compatible with current IPP clients and servers.  The problem is not 
always
on the printer (server) side, since the client can also send media names 
to
the server.

RB >> I would prefer to specify "not case sensitive" but I see now that 
for
IPP compatibility it is best to require lower case.

RB >> A good design will always convert received characters to a specific
case and send any characters in the specified case.  It would be best if
all protocols specified and then the sender could use common code for all.

BTW, I have seen some IANA Registries where the tokens are all upper case.
That is why I included alternative c) above as well.

Bottom line: The Media standard is writing conformance for other standards
that reference the Media standard (like the IPP Notification Standard 
placed
requirements on Delivery Method documents), not conformance for Printers 
or
clients.

RB >> I agree, and lower case would be the best choice for conformance.

See my replies to your message below preceded by TH>

Comments?

Tom

-----Original Message-----
From: Bergman, Ron [mailto:[email-masked]]
Sent: Monday, April 02, 2001 08:57
To: Hastings, Tom N
Cc: [email-masked]'; [email-masked]'; [email-masked]'
Subject: Media Names, case sensitivity

Tom,

I am curious as to why you changed my original statement that the names 
are
not case sensitive to the the complicated set of requirements that, in
effect,
states "do whatever you want, but explicitly state what you want."

TH> The draft is stating that other standards that use these names do what
they want, but those standards (such as IPP, UPnP, Printer MIB, etc.) MUST
say what they require.

Your specification puts a larger burden on the Printer, since the printer
will
have to conform to the applications.  (The printer may have to do a case
conversion for some applications and not others.)  So the printer (or 
other
device) must know the exact format required by the application.

TH> The Printer will have to conform to whatever standards the Printer
chooses to support, i.e., IPP, UPnP, Printer MIB, ...

Just stating the names are not case sensitive, puts the burden on the
client.

TH> I disagree.  It depends on what the other standards say about case
sensitivity.  Perhaps the Media standard can RECOMMEND that other 
standards
REQUIRE all lower case, as I suggested above.  Wouldn't that help?

RB >> Do any other standards, besides IPP exist?

But the client simply has to do a conversion on all names received to
whatever
case he has chosen for his tables.  The client does not need to know what
the printer is sending.

Whatever we conclude,, this text needs will be moved from section 5 to 
section 10, since it applies to all the names in the specification.

TH> I agree it should be moved to a section that is common for all the
names.  However, section 10 is the authors section.

RB >> I should have said the conformance section.

    Ron