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BIRD ID#:        139.2
ISSUE TITLE:     Reserved_Parameters Order
REQUESTER:       Bob Ross, Teraspeed Consulting Group
DATE SUBMITTED:  June 21, 2011 
DATE REVISED:    July 12, 2011, September 16, 2011
DATE ACCEPTED BY IBIS OPEN FORUM:  September 16, 2011

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STATEMENT OF THE ISSUE:

In general there are no order dependency rules in the .ami file.  The
(required) Reserved_Parameters section is not required to appear before the
Model_Specific section.  However, with approved BIRD126 (adding AMI_Version)
the Reserved_Parameters branch needs to appear first for IBIS Version 5.1
and above so that new features can be immediately identified and processed
according to the correct Specification version.


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STATEMENT OF THE RESOLVED SPECIFICATIONS:


On Page 143, change the paragraph


|               The 'Reserved_Parameter' section is required while the
|               'Model_Specific' section is optional.  The sub-trees can be
|               in any order in the parameter file.  The '|' character is the
|               comment character.  Any text after the '|' character will be
|               ignored by the parser.
|

to

|               The 'Reserved_Parameter' section is required while the
|*              'Model_Specific' section is optional.  For AMI_Version 5.1
|*              and above, the Reserved_Parameter sub-tree shall appear
|**             before the Model_Specific sub-tree.  Sub-trees of these
|**             sub-trees can be in any order in the parameter file. The
|**             '|' character is the comment character.  Any text after the 
|***            '|' character until the end of the line will be ignored by
|***            the parser.
|


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ANALYSIS PATH/DATA THAT LED TO SPECIFICATION

In all IBIS formats (.ibs, .pkg, .ebd, .icm) and Touchstone 2.0, the Version
information is required as the first keyword so that the remaining content
can be immediately parsed at the specified Version.  This is now very
desirable for .ami files with the approval of BIRD126 which already mandates
that AMI_Version appear first under the Reserved_Parameters sub-tree. 

The diagram organization on page 144 shows Reserved_Parameters first, and
this organization appears already to be common practice.

With the new requirement that Reserved_Parameters be positioned first,
the AMI_Version can be determined, and .ami file legal set of parameters and
structures can be parsed during the first pass.  Otherwise a separate pass
might be needed.

BIRD139.1:

The sentence "Sub-trees of these sub-trees can be in any order in the
parameter file." was inserted to replace removed text about sub-tree order
dependency per discussions at the June 24, 2011 IBIS Teleconference meeting.
The changes are noted by |** lines.

BIRD139.2:

The final sentence was changed to "Any text after the '|' character until
the end of the line will be ignored by the parser." based on a comment by
e-mail and at the September 16, 2011 teleconference meeting.  The added
clarification, 'until the end of the line' restricts the extent that text
is to be ignored.  The modification is noted by |*** lines.


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ANY OTHER BACKGROUND INFORMATION:

The word "sub-tree" is not modified in this BIRD.  However the word
"branch" appears in BIRD126.  The final terminology might be decided later
for overall IBIS-AMI terminology consistency.

This BIRD draft was discussed during the June 21, 2011 ATM Task Group
meeting and there were no objections or issues concerning this BIRD.

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