Organisation of Hypertext information falls naturally into two aspects:
WASD online information resources will have VMS file space provided for them.
This will comprise a single top level directory under which data files and
subdirectories can be organised by the manager(s) as required. PC users will
be able to USE to their area.
2.1 - File Paths
The information in this section contains some technical information on Hypertext referencing and links. This is directly applicable to specifying files in menus (see 3 - Menus).
File and directory locations are specified using URL syntax (see 5 - Glossary), where slash-separated (``/'') elements delineate a hierarchy leading to a data item. Anyone familiar with the syntax of the Unix file system, or the MS-DOS file system (where back-slashes are hierarchy delimiters), will feel at home with URL syntax. File specifications under VMS are not case-sensitive.
A VMS directory specification
WEB:[HTML.HTML-PRIMER]would be represented in URL syntax as
/web/html/html-primer/and a VMS file specification
WEB:[HTML.HTML-PRIMER]HTML-PRIMER.HTMLrepresented as
/web/html/html-primer/html-primer.html
- NOTE -
It is not required (although not forbidden) to supply a VMS master file directory component (``[000000]'', ``[000000.'', etc.) in a URL specification. Hence the file specificationWEB:[000000]HOME.HTMLshould be represented as/web/home.html
A file may be specified using an absolute, or full path. This must specify the location of the file exactly. Absolute paths always begin with a forward-slash (``/''). For example:
/web/committee/minutes/1994/1994-09-27.txt /web/committee/constitution.txt /web/committee/membership/fred-bloggs.txt
A file may be specified relative to its current location. That is, a current document (or menu) may specify another document file relative to itself. This may be at the current level, a subdirectory, or in another part of the directory tree related to the current. Relative paths never begin with forward-slash (``/'').
For 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
Documents 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
Documents 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.txt ../other_committee/1993/reports/balance-sheet.txt ../../other_section/committee/constitution.txt
Arbitrary files may not be accessed.
The Basic HyperText Server (BHTS, see 5 - Glossary) will only access files where the path begins with the string WEB. This is done as a security measure, preventing clients requesting the server to roam all through the file system. It is effectively constrained to specified hierarchies using this mechanism.
If a new hierarchy is required contact VMS systems management.
- NOTE -
The server executes as a normally privileged process and cannot be used to subvert security. It only has access to files are world-readable. Preventing it from roaming the file system keeps the number of security alarms at an acceptable level!
As the server executes as a normally privileged process, files it accesses must be world-readable, or specifically have the server account granted access in an ACL.
A protected file results in the server returning an error message and aborting the request.