Proposed Network Standard Data Pathname syntax
RFC 615

Document Type RFC - Unknown (March 1974; No errata)
Obsoleted by RFC 645
Last updated 2013-03-02
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Network Working Group                                     D. Crocker (UCLA-NMC)
Request for Comments: 615                                                MAR 74
NIC #21531

                           Proposed Network
                     Standard Data Pathname Syntax

There seems to be an increasing call for a Network Standard Data Pathname
(NSDP); that is, a standardized means of referring to a specific location
for/of a collection of bits somewhere on the Network.

The reasons for a standard or virtual anything have been discussed, at
length, elsewhere and will not be elaborated upon here. Rather than
attack the entire issue of virtual pathnames, I wish only to propose a
standardized SYNTAX for specifying pathnames. Such a standard will be
useful for 1) users who are unfamiliar with a site or who use several
different sites and do not want to have to remember each site's
idiosynchracies, 2) programs accessing data at several other sites, and
3) documentation:

The syntax allows the user to specify the necessary network, host,
peripheral device, directory, file, type, and site-specific fields.
Adding other fields, as needed, is expected to be quite simple.

First the BNF:

   <NSDP> ::= % <bulk> <cr><lf>
 
   <bulk> ::= <field> / <field> <bulk>

   <field> ::= <key> <L-delim> <name> <R-delim>

   <key> ::= NETWORK / HOST / PERIPHERAL/ DIRECTORY /
             FILE / TYPE / SITEPARM / N / H / P / D / F /
             T / S

<L-delim> ::= any printable character that is not in the
              succeeding <name> field and that is
              acceptable to the object site: For visual
              aesthetics and to facilitate human parsing,
              anytime <L-delim> is a left-bracket
              character (<, [, (, _), <R-delim> must be
              the complementary right-bracket character
              (>, ], ), |).

<name> ::=    any sequence of characters acceptable to the
              object site. This is the actual data field
              with the file, directory, device (or
              whatever) name.

<R-delim> ::= Either 1) the same character as <L-delim> or
              2) if the <L-delim> character is a
              left-bracket character (<, [, (, _) then its
              complementary right-bracket (>, ], ), |).

                                 -1-

<cr> ::=      carriage-return

<lf> ::=      line-feed

And some elaboration:

The syntax allows <name> fields to be an arbitrary number of rs long.
Case is irrelevant to the syntax, though some sites will care about case
in <name> fields:

<Key> indicates what part of the pathname the next <name> is going to
refer to: The single-character keys are abbreviations for the respective
full-word keys:

<Fields> ARE order dependent, but defaulted ones may be omitted. The
order is as indicated for <key>s: That is, Network, Host, ..: Siteparm:

Fields may be repeated, as appropriate for the object site; that is,
multiple Directory fields, etc:

The validity of any combination of <field>s is entirely site-dependent:
For example, if a site will accept it, an NSDP with a Host field, and
nothing more, is permissible:

<delim> is used to delimit the beginning and end of the <name> field:

Explanation of <key>s:

       NETWORK or N:   Currently, only ARPA is defined.

       HOST or H:      Reference to host, by official name or
                       nickname or number: The default radix is
                       ten; a numeric string ending with "H"
                       indicates hexadecimal, "O"(oh) indicates
                       octal, and (gratuitously) "D" indicates
                       decimal:

      PERIPHERAL or P: Peripheral device being referred to:

      DIRECTORY or D:  Name of a directory which contains a
                       pointer to the entity (directory or
                       filename) specified in the following
                       <field>:

      FILE or F:       Basic name of the file or data set:

      TYPE or T:       Optional modifier to filename: (Tenex
                       calls it the extension.)

      SITEPARM or S:   A parameter, such as an access
                       specification or version number, peculiar
                       to the object site. The content of the
                       <name> field must serve to identify what
                       Siteparm is involved. Each site will be
                       responsible for defining the syntax of
                       Siteparm <name>s it will accept.

                                   -2-

Some reserved PERIPHERAL <name>s:

      DISK or DSK:     Immediately accessible, direct-access
                       storage.

      ONLINE or ONL:    Whatever immediately-accessible (measured
                        in fractions of a second) storage the
                        user accesses by default; usually disk:

      TAPE or TAP:      Industry-compatible magnetic tape:

      TAPE7 or TP7:     7-Track industry compatible tape:

      TAPE9 or TP9:     9-Track industry compatible tape:
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