Data Organisation#

HFRD Hypertext Menu Primer

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2 - Data Organisation




GOrganisation of Hypertext information falls naturally into two aspects:

    ,
  1. The physical organisation of the files.L
  2. The logical organisation of the information (structure, relationships, interrelationships, etc.)
 FAs this document is a primer, this section will mainly concern Nitself with the physical organisation of data, which coupled with an emphasis 2on the menuing capability within HFRD (see_3 - Menus), naturally results in a somewhat hierarchicalMlogical organisation. Discussion of inter-document referencing is best left 4to texts on HTML. Basic references are provided in 76 - References. 

Physical Organisation




OHFRD online information resources will have VMS file space provided for them. KThis will comprise a single top level directory under which data files and Nsubdirectories can be organised by the manager(s) as required. PC users will 'be able to USE to their area. 

2.1 - File Paths



GThe information in this section contains some technical information on LHypertext referencing and links. This is directly applicable to specifying Nfiles in menus (see 3 - Menus). 

AFile and directory locations are specified using URL syntax (see ]5 - Glossary), where slash-separated (``/'') elements Odelineate a hierarchy leading to a data item. Anyone familiar with the syntax Kof the Unix file system, or the MS-DOS file system (where back-slashes are Ohierarchy delimiters), will feel at home with URL syntax. File specifications !under VMS are not case-sensitive.

A VMS directory specification #

  HYPERDATA:[HTML.HTML-PRIMER]
%would be represented in URL syntax as#
  /hyperdata/html/html-primer/
and a VMS file specification 3
  HYPERDATA:[HTML.HTML-PRIMER]HTML-PRIMER.HTML
represented as3
  /hyperdata/html/html-primer/html-primer.html


Note:

FIt is not required (although not forbidden) to supply a VMS master Efile directory component (``[000000]'', ``[000000.'', etc.) in a 1URL specification. Hence the file specification "
  HYPERDATA:[000000]HOME.HTML
should be represented as
  /hyperdata/home.html
 #

2.1.1 - Absolute File Path




AA file may be specified using an absolute, or full path. DThis must specify the location of the file exactly. Absolute paths 3always begin with a forward-slash (``/''). For example: 7

  /hyperdata/committee/minutes/1994/1994-09-27.txt'  /hyperdata/committee/constitution.txt1  /hyperdata/committee/membership/fred-bloggs.txt
0

2.1.2 - Partial (or Relative) File Path




GA file may be specified relative to its current location. That Lis, a current document (or menu) may specify another document file relative Lto itself. This may be at the current level, a subdirectory, or in another Cpart of the directory tree related to the current. Relative paths /never begin with forward-slash (``/''). 

IFor example, documents at the same level as the current may be specified %without any hierachy being indicated:

  1994-07-22.txt  1994-08-24.txt  1994-09-27.txt


KDocuments at an inferior point in the hierarchy may be specified as in the following example:

  1993/1993-02-17.txt  1993/reports/membership.txt  other/etc.txt


IDocuments in a related part of the hierarchy may be referenced using the >``../'' construct. As with MS-DOS and Unix this syntax.indicates the immediately superior directory. -

  ../other_committee/1993/1993-02-17.txt3  ../other_committee/1993/reports/balance-sheet.txt0  ../../other_section/committee/constitution.txt


2.1.3 - HYPERDATA Root




+Arbitrary files may not be accessed.

eThe Basic HyperText Server (BHTS, see 5 - Glossary) will only 3access files where the path begins with the string 9HYPERDATA. This is done as a security measure, Hpreventing clients requesting the server to roam all through the Kfile system. It is effectively constrained to specified hierarchies using this mechanism.

?If a new hierarchy is required contact VMS systems management. 

Note:

KThe server executes as a normally privileged process and cannot be used to Osubvert security. It only has access to files are world-readable. Preventing Jit from roaming the file system keeps the number of security alarms at an acceptable level!
 !

2.1.4 - File Permissions




PAs the server executes as a normally privileged process, files it accesses must Mbe world-readable, or specifically have the server account granted access in an ACL. 

OA protected file results in the server returning an error message and aborting the request.




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