Electrical computers and digital processing systems: multicomput – Distributed data processing – Client/server
Reexamination Certificate
1999-06-29
2003-02-18
Sheikh, Ayaz (Department: 2155)
Electrical computers and digital processing systems: multicomput
Distributed data processing
Client/server
C709S203000, C709S230000, C370S392000, C455S403000, C455S405000
Reexamination Certificate
active
06523062
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a computer system, and deals more particularly with a method, system, and computer-readable code for facilitating network delivery of Wireless Markup Language (WML) decks (or decks in similar notations) to memory-constrained client devices such as Wireless Application Protocol (WAP) devices, by applying a novel deck-reduction process to the decks, such that the decks are reduced by fragmentation into new decks of a manageable size.
2. Description of the Related Art
The Wireless Application Protocol, or “WAP”, is an industry standard protocol specification created for mobile Internet use. WAP was defined by the WAP Forum, and specifies protocols for delivering information over a wireless network to WAP client devices (where a “WAP client device”, or “WAP client”, is a device conforming to the WAP architectural requirements).
The WAP Forum has also defined the Wireless Markup Language, or “WML”, which is a markup language for documents that are intended for delivery to WAP clients. A markup language uses specially-designated constructs referred to as “tags”to delimit (or “mark up”) information. WML is based on the Extensible Markup Language (“XML”), which is a standard grammar for markup languages. In the general case, a tag is a keyword that identifies what the data is which is associated with the tag, and is typically composed of a character string enclosed in special characters. “Special characters” means characters other than letters and numbers, which are defined and reserved for use with tags. Special characters are used so that a parser processing the data stream will recognize that this a tag. In XML and its derivative notations, a tag is inserted preceding its associated data: a corresponding tag is also inserted following the data, to clearly identify where that data ends. As an example of using tags, the syntax “<email>” could be used as a tag to indicate that the character string appearing in the data stream after this tag is to be treated as an e-mail address; the syntax “</email>” would then be inserted after the character string, to delimit where the e-mail character string ends. (Refer to “Wireless Application Protocol Wireless Markup Language Specification Version 1.1 (WAP WML), Proposed Version Feb. 3, 1999” for more information on WML, and to “Extensible Markup Language (XML), W3C Recommendation Feb. 10, 1998” for more information on XML. These documents are available on the World Wide Web from Web sites http://www.wapforum.org and http://www.w3.org, respectively.)
WML is specifically designed for the limitations that are often inherent in the client devices used in the mobile, or wireless, computing environment. Client devices common in this environment include cellular phones, screenphones, pagers, and laptop computers. While laptop computers may be nearly equivalent in features and capabilities to non-mobile computing devices such as desktop computers, many of the other devices used in the wireless environment tend to be small, handheld devices that have limited memory and storage, as well as limited display space. Section 4.5, “Device Types”, of the WML specification provides a description of the characteristics of devices for which WML was designed. These characteristics include small display screen size, with low resolution; limited user input facilities; low power CPUs and small memory size; and capable of supporting only low bandwidth connections, therefore resulting in high latency. An example of this type of device is the Nokia 7110, a WAP-enabled cellular phone with a maximum display area of 6 lines of text. Another example device is the WorkPad available from the International Business Machines Corporation (“IBM”). This device is a handheld computer typically configured with several megabytes of storage, where that storage is as Random Access Memory (“RAM”) to avoid the system overhead associated with other types of storage such as disk drives. (“WorkPad” is a registered trademark of IBM.)
WML is defined using a metaphor of a deck of cards, where a WML deck is comprised of one or more cards. A WML deck is analogous to a document in XML, and is the unit of information identified by a URL (Uniform Resource Locator). Thus, a WML deck is also the unit of transmission, as it comprises the information delivered to the client machine in response to a request (e.g. from a client browser) for a particular URL. Each card within the deck specifies text and input elements, and is defined in Section 4.1, “Definitions”, of the WML specification as “a single WML unit of navigation and user interface”. Thus, when a document author creates a WML deck, he divides the information into cards using “<card>” and “</card>” tags to mark the beginning and end of each card.
Authors creating documents as WML decks typically create the decks to be small in size, to accommodate the memory and processing limitations inherent in the target client devices. However, problems often arise when a user of a WAP-enabled device requests a document that was not created specifically with the wireless device limitations in mind. For example, it is becoming commonplace for XML documents (created irrespective of the client device) to be transcoded or otherwise transformed for downloading. When the target device is a relatively powerful machine with a large storage capacity such as a desktop computer, then downloading the XML document is unlikely to create problems. However, when the target device is a constrained device, then there may not be sufficient space for receiving and storing the document on the device. In addition, the processing capabilities of a constrained device may be insufficient for a document created without regard to the limitations of these devices.
Extensible Stylesheet Language (“XSL”) style sheets provide an efficient means of filtering documents (such as XML documents), by defining translations on an input document that create only a specific set of desired document elements in the resulting output document. As is known in the art, a “style sheet” is a specification of a style that is to be used when presenting a document. Style sheets may also be utilized to describe transformations from one document type to another, such as transforming an XML document to a WML document. Style sheets may also be used as filters which describe transformations to reduce the amount of document content while maintaining the original document type. However, XSL style sheet filtering does not provide a means for limiting the size of the output document. WML decks in excess of 1 kilobyte in size may overload a constrained storage device, leading to undefined behavior when the device attempts to process the deck. From a user's perspective, it is unacceptable to allow this undefined behavior to occur.
The Wireless Application Protocol Binary XML notation, or “WBXML”, also uses a card and deck metaphor. WBXML is a compact binary form of XML, designed to reduce transmission size of XML documents in the wireless environment by performing a binary encoding of the document content. (The WBXML specification is available from the www.wapforum.org Web site.)
There are currently no known techniques for enabling constrained WAP client devices to receive WML or WBXML decks, and provide predictable, expected results from processing these decks, when a deck exceeds the size restrictions of the client device. Accordingly, what is needed is a technique that enables WML or WBXML decks to be transformed for transmission to a client device such that the decks are first reduced to a manageable size, but without any loss of document content.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a technique with which oversized decks may be reduced to a manageable size without loss of content.
Another object of the present invention is to provide a technique whereby this deck reduction is performed on Wireless Markup Language (WML) decks.
It is a further object of the present i
Bridgman Thomas E.
Lection David B.
Wesley Ajamu A.
Doubet Marcia L.
International Business Machines - Corporation
Nguyen Thu Ha
Ray-Yarletts Jeanine S.
Sheikh Ayaz
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