Draft of a RFC (Informational Protocol) April 16, 1996 Category: Informational Tsuyoshi Hayashi Barrier Free, Inc. Extended Uniform Resource Locator (XURL) Status Of This Memo This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Abstract This document proposes an Extended Uniform Resource Locator (XURL), a compact string representation for a resource both available via the Internet and not. By using the XURL, we can indicate any types of resources and also integrate the "two" worlds, the Internet world and the real world. The XURL scheme is a extended version of the Uniform Resource Locator (URL). 0. About "Resource" In this memo, "resource" means any type of things, matters, concepts, or spirituals; a lot of fact information, databases, computer files, paper files, hardwares, softwares, both online and offline information services, shops, foods, animals or flowers, human beings (including you or I), atoms, genomes, good or bad ideas, devices, feeling, Genki mind or something else. Something are on the Internet, something are around you or me. 1. Introduction Uniform Resource Locator (URL) is a very useful code for the Internet community. By using this code, we can indicate (point out) a lot of resources (computer files or services) provided on the Internet. But URLs are only effective in the Internet field. Although there are a lot of resources outside the Internet, we cannot indicate or identify them from the Internet side. In a few years, more information services will be provided on the Internet. But, of course, many resources will be still in the real world, and probabry something will be both. After all, we have to handle two different-type resources; one is resources on the Internet, another is resouces outside the Internet. We know how to handle the former today, but we have no way to handle the latter yet. Therefore, I think we need the XURL in order to both indicate resources outside the Internet and integrate the two worlds. You can use XURL anytime you want to indicate resources inside or outside the Internet world. For example, you can indicate and/or trace a copyright-holding object (which is on the Internet or not) by the XURL. Any data on any Internet servers or any papers someone wrote are the same. By using the XURL, maybe we may be able to break the barrier between the Internet world and the Real world. In addition, the XURL has a function for the digital timestamp service if appropriate organizations provide digital siging and notarizing systems. 2. Description If you would like to indicate a resource on the Internet, you can use both URL [URL] and XRUL. On the other hand, if you would like to indicate a resource outside the Internet, you have to use this XURL scheme in following format. 2.1 General XURL Syntax A full BNF description of the XURL syntax is not given in this document. Sorry. In general, XURLs are written as follows: X.. An XURL starts with a letter either "X" or "x". (A uppercase of "X" is recommended.) Next, the XURL contains the name of the scheme being used () followed by a period, the timestamp being used () followed by a period, and then a string (the ) whose interpretation depends on the scheme. Scheme names consist of a sequence of characters. The allowed letters are depended on the scheme. For resiliency, systems interpreting XURLs should treat upper case letters as equivalent to lower case in scheme names (e.g., allow "REAL" or "Real" as well as "real"). 2.2 Usable Character Set for XURLs XURLs are sequences of characters, i.e., letters, digits, and special characters. An XURLs may be represented in a variety of ways: e.g., ink on paper (printed on paper), data in computer file, or one's memory. XURLs are written only with the graphic printable characters of the US-ASCII [ASCII] coded character set. The octets 80-FF hexadecimal are not used in US-ASCII, and the octets 00-1F and 7F hexadecimal represent control characters; these must be encoded. If you would like to use some non-US-ASCII character set in the XURL, it must be encoded within printable US-ASCII character set. For example, if you want to use a Japanese Kanji characters set, it must be encoded by ISO-2022-JP [ISO2022] or the other appropriate ways. 2.3 Specific Schemes The schemes covered are: inet for resources on the Internet inet+ for resources not provided on the Internet yet real for resources exist in the real world feel for resources held in one's heart misc for unknown things 2.4 Timestamp Format and Meaning The timestamp consistes of following parts: like "19950415" or "15Apr1996" (means April 15, 1996) @