rfc1691.txt

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RFC 1691               CDL Document Architecture             August 1994


Physical References File Example

+0|CORNELL|OLINLIB|00000001|Boole, Mary Everest||Philosophy Of Algebra||

|0|1|00000002|5|1||   (File ref. #2 = Phys. ref. #5 = 600dpi TIFF image)
|0|2|00000003|5|2||   (File ref. #3 = Phys. ref. #5 = 100dpi TIFF image)
|0|3|00000004|6|1||   (File ref. #4 = Phys. ref. #6 = 600dpi TIFF image)
|0|4|00000005|6|2||   (File ref. #5 = Phys. ref. #6 = 100dpi TIFF image)

   Note that in the above, it is guaranteed that file references 2 and 3
   are two different versions of the same page, as are file references 4
   and 5.

Logical Structure File

   The Logical Structure file is the component of the document structure
   which offers "views" of a document and links images together
   logically to define documents. The file is actually an unloaded tree;
   when a document is "opened", the file is read and the tree
   reconstructed. By convention, all Logical Structure files contain one
   logical structure "PAGES" which defines the document by listing the
   pages in the order in which they appeared in the original document.

Document Structure lines

   Field   Description                  Comments
   -----   ----------------------       ----------------------------
     1     Parent structure number      Structure is a child of...
     2     Sequence number
     3     Logical Structure name       Label for this structure
     4     Structure number             Equal to Physical Reference file
     5     Logical Children             # of logical children of this
                                          structure
Document Structure lines (continued)

   Field   Description                  Comments
   -----   ----------------------       ----------------------------
     6     Physical Children            # of physical children of this
                                          structure
     7     References                   # of references to this
                                          structure within this document
                                        (for how many structures is this
                                         a substructure)








Turner                                                          [Page 6]

RFC 1691               CDL Document Architecture             August 1994


Logical Structure File Example

|0|0|ROOT|0|4|0|0|            Structure 0, ROOT, has 4 logical children
|0|1|PAGES|1|100|0|1|         Str. 1, PAGES, has 100 logical children
|0|2|CONTENTS|2|22|0|1|       Str. 2, CONTENTS, has 22 logical children
                              ...has no physical children
 ...
|1|1|Production note|5|0|2|2| Str. 5 is child of structure 1
                              ...has a label "Production note"
                              ...has no logical children
                              ...has 2 physical references
                              ...is referenced twice in this document
|1|2||6|0|2|1|                Str. 6 has no label
|1|3||7|0|2|1|                Str. 7 has 2 physical references
|1|4||8|0|2|1|                Str. 8 is referenced only here
|1|5||9|0|2|1|                Str. 9 is 5th sequential child of PAGES
 ...
|1|99||103|0|2|2|
|1|100||104|0|2|2|
|2|1|Production note|105|1|0|1|          Str. 105 is a child of str. 2
|2|2|Title page|106|1|0|1|               Str. 106 has 1 logical child
|2|3|Table of contents|107|2|0|1|
|2|4|Chapter 1. From Arithmetic to Algebra|108|6|0|1|
|2|5|Chapter 2. The Making of Algebras|109|4|0|1|
|2|6|Chapter 3. Simultaneous Problems|110|4|0|1|
|2|7|Chapter 4. Partial Solutions...|111|3|0|1|
|2|8|Chapter 5. Mathematical Certainty...|112|3|0|1|
|2|9|Chapter 6. The First Hebrew Algebra|113|8|0|1|
|2|10|Chapter 7. How to Choose our Hypotheses|114|9|0|1|
|2|11|Chapter 8. The Limits of the Teachers Function|115|5|0|1|
|2|12|Chapter 9. The Use of Sewing Cards|116|4|0|1|
 ...
|2|20|Chapter 17. From Bondage to Freedom|124|5|0|1|
|2|21|Appendix|125|2|1|1|
|2|22|advertisements|126|4|1|2|
|105|1|Production note|5|0|2|2|          Str. 5 is a child of str. 105
|106|1|Title page|11|0|2|2|              2nd reference to str. 11
|107|1|7|15|0|2|2|
|107|2|8|16|0|2|2|
 ...
|126|4||104|0|2|2|










Turner                                                          [Page 7]

RFC 1691               CDL Document Architecture             August 1994


Implementation Details

   The tuple <library ID>+<collection ID>+<document ID>+<filetype>+
   <file reference> is guaranteed to locate a file.  A file locator
   program will translate between this tuple and the fully-qualified
   path and file name in the underlying file system.  While a library
   will always have a hierarchical nature corresponding to UNIX file
   systems, the order of the hierarchy will be flexible to accommodate
   optimization efforts.  Each level of the hierarchy will have an INFO
   file that describes the order of the lower levels of the hierarchy.
   The file locator program will read these files as it navigates the
   directory structure of the file system when a library, collection, or
   document is opened.  Two examples follow:

     Example 1.  Hierarchy is LIBRARY, COLLECTION, DOCUMENT, FILETYPE.

  /<library name>
          LIBINFO.TXT                      Description of library
          /<collection name>
                 COLINFO.TXT               Description of collection
                 /<document ID>
                       DOCINFO.TXT         Description of document
                       LOGSTR.000          Logical structure file
                       PHYSREF.000         Physical reference file
                       /<filetype1>
                               00001.TIF
                               00002.TIF
                               ...
                       /<filetype2>
                               00001.TIF
                               00002.TIF
                               ...



















Turner                                                          [Page 8]

RFC 1691               CDL Document Architecture             August 1994


   Example 2.  Hierarchy is LIBRARY, FILETYPE, COLLECTION, DOCUMENT.

  /<library name>

          LIBINFO.TXT                         Description of library
          /<filetype1>
                  /<collection name>
                         COLINFO.TXT          Description of collection
                         /<document ID>
                               DOCINFO.TXT    Description of document
                               LOGSTR.000     Logical structure file
                               PHYSREF.000    Physical reference file
                               00001.TIF
                               00002.TIF
                               ...
          /<filetype2>
                  /<collection name>
                         COLINFO.TXT          Description of collection
                         /<document ID>
                               DOCINFO.TXT    Description of document
                               LOGSTR.000     Logical structure file
                               PHYSREF.000    Physical reference file
                               00001.TIF
                               00002.TIF
                               ....

   This implementation involves some redundancy, but it permits complete
   copies of a collection to be mounted on different file systems for
   performance considerations.  In particular, the second scheme would
   facilitate storing all low-resolution images on high-speed magnetic
   disk for fast access, and all high-resolution images on slower, less
   expensive storage.  This will also facilitate authorizing access to
   low-resolution images by other software systems (FTP, Gopher) while
   restricting access to high-resolution images.

















Turner                                                          [Page 9]

RFC 1691               CDL Document Architecture             August 1994


Security Considerations

   Security issues are not discussed in this memo.

References

   [1] Turner, W., "Cornell Digital Library Document Architecture,
       Version 1.1 - 3/22/94", Library Technology Department, Cornell
       University.

Author's Address

       William Turner
       Library Technology
       502 Olin Library
       Cornell University
       Ithaca, NY  14853

       Phone: [phone]
       Fax:   [phone]
       EMail: [e-mail]






























Turner                                                         [Page 10]