Valid attributes include ACCESS-METHOD, CLOSURE, DESCRIPTION, FORWARDING-POINTER, KEYWORDS, LAST-REFERENCED, LAST-WRITER, LOCKS, OWNER, REPLICAS, SIZE, STORAGE-LOCATION, TTL, TTL-EXPIRES. VERSION-NUMBER, VIRT-SYS, WELL-KNOWN-NAMES, and WRITE-DATE.
Prospero maintains the following system defined attributes for each Prospero object:
This is a tuple of at least 5 elements. The first element is the name of the access method. Currently supported values are AFTP, GOPHER, AFS, NFS, FTP, WAIS, and LOCAL. The next 2 elements are the host-type and host-name of the host to which the access method should connect in order to retrieve the object. A port number may be included as part of the hostname, if relevant. If they are zero-length tokens (''), then they default to the host-type and host-name specified in the link. The next 2 elements are the hsoname-type and hsoname which the access method will use to retrieve the object. If they are zero-length tokens, then they default to the hsoname-type and hsoname specified in the link. This constraint on format applies to all access methods. If a particular type of access method doesn't need one of these fields, then it still must be specified, but the access method is free to ignore it. The whole point of the '' shorthand is merely to save bytes in the protocol messages. It is always appropriate to send them fully expanded, and not use the '' shorthand.
The sixth and subsequent elements are dependent upon the particular access method. For AFTP and FTP, the sixth element will be BINARY or TEXT. For NFS, the sixth element will be the name of the filesystem on the remote host. LOCAL, and AFS have only five-element names.
The GOPHER access method may have five or six elements in the name. The actual protocol used to retrieve a document or object through Gopher varies depending on its Gopher item-type. (See Internet RFC 1436 for details on the interpretation of the Gopher item-type characters.). This item type is usually the 1st character of a Gopher document or object's selector string (the hsoname element of the access method). However, the protocol does not require that this be the case. If a sixth token is present in a GOPHER access method, it will be treated as the Gopher item-type character; otherwise, the item-type will be taken from the 1st character of the hsoname element.
ATTRIBUTE FIELD ACCESS-METHOD GOPHER INTERNET-D MERMAID.MICRO.UMN.EDU(150) ASCII '1/Fun Stuff/Pyrotechnics/PyroGuide 1'
This access method could also be displayed in the six-token format as:
ATTRIBUTE FIELD ACCESS-METHOD GOPHER INTERNET-D MERMAID.MICRO.UMN.EDU(150) ASCII '1/Fun Stuff/Pyrotechnics/PyroGuide 1' 1
Andrew File System names are the same irrespective of what host one is using them from. Therefore, the host-name token in the access method is irrelevant and is ignored by the client.
ATTRIBUTE FIELD ACCESS-METHOD AFS DUMMY DUMMY ASCII /grand.central.org/doc/afs/dce/usenix90/README
This file can be retrieved by NFS mounting the /auto/gum/gum filesystem on the host PROSPERO.ISI.EDU. Note that the server is responsible for knowing which client machines it will allow to NFS mount that filesystem.
ATTRIBUTE FIELD ACCESS-METHOD NFS INTERNET-D PROSPERO.ISI.EDU ASCII ftp/pub/prospero/README-prospero-documents /auto/gum/gum
hsoname tokens in the FTP access method are full local hostname paths that one would give when using full FTP to the host.
ATTRIBUTE FIELD ACCESS-METHOD FTP INTERNET-D PROSPERO.ISI.EDU ASCII /ftp/pub/prospero/README-prospero-documents TEXT
hsoname tokens in the AFTP access method are pathnames relative to the root of the anonymous FTP area.
ATTRIBUTE FIELD ACCESS-METHOD AFTP INTERNET-D PROSPERO.ISI.EDU ASCII /pub/prospero/README-prospero-documents TEXT
If one is querying from a host which has a file accessible via the local filesystem, and if the server has knowledge of this fact, a LOCAL access method will also be returned for a file. For the LOCAL access method, the host-name token in the access method is ignored.
ATTRIBUTE FIELD ACCESS-METHOD LOCAL '' '' ASCII /auto/gum/gum/ftp/pub/prospero/README-prospero-documents
Although the OWNER field may be referred to with the OWNER ACL type, we don't really encourage people to use it as a shorthand for granting access rights. Its primary purpose is informational.
Note that the object's name is not one of its attributes. The object's name is the concatenation of the name components starting from the active virtual system. An object may have different names in different virtual systems, or even multiple names within a single virtual system.