Providing a directory of frequently used hyperlinks on a remote server

Access to hypermedia servers connected to networks such as the Internet can be provided through mobile devices such as wireless telephones. Hypermedia links such as Uniform Resource Locators (URL) are used to identify and control access to resources on the network. These links are usually very long, are difficult to remember, and are difficult to enter into many mobile devices. These difficulties could be overcome by storing lists of frequently used links or "bookmarks" in the mobile device but limited memory in the device generally prevents this. This limitation is overcome by storing designated hypermedia links on a bookmark server. In one embodiment, the URL of the bookmark server is sent to the mobile device during initialization of the device. By allowing a user can to save, retrieve and maintain lists of frequently used links on the bookmark server, access to favorite resources on a network is greatly simplified.

MICROFICHE APPENDIX 
A listing of particular embodiments of computer programs incorporating 
features of the present invention is provided in a microfiche appendix to 
this disclosure and is incorporated herein by reference. This appendix 
consists of 17 microfiche having a total of 1641 frames. 
AUTHORIZATION WITH RESPECT TO COPYRIGHTS 
A portion of the disclosure of this patent document, including but not 
limited to the microfiche appendix, contains material which is subject to 
copyright protection. The copyright owner has no objection to the 
facsimile reproduction by anyone of the patent document or the patent 
disclosure, as it appears in the Patent and Trademark Office patent file 
or records, but otherwise reserves all copyright rights whatsoever. 
TECHNICAL FIELD 
The present invention relates generally to devices and methods for 
interacting with hypermedia servers connected to networks. More 
particularly, the present invention pertains to structures and methods of 
system interactions arranged such that practical access to hypermedia 
servers is available to a wider range of devices such as wireless 
telephones. 
BACKGROUND ART 
Although networks like the Internet have been in existence for years, they 
have not been a popular medium of information exchange until very 
recently. The recent explosive growth in usage of the Internet, for 
example, is due in large part to the development of devices and methods 
that simplify the actions a user must take to access multimedia 
information stored by network servers. One significant development is the 
use of hyperlinks which allows disparate pieces of information to be 
organized in nonsequential ways and which allows a user to easily navigate 
among the linked information. By assigning a unique identifier to each 
distinct piece of multimedia information available throughout a network, 
information can be readily accessed without regard to where it is stored. 
Network clients and servers participating in such a "hypermedia" network 
are referred to herein as hypermedia clients and hypermedia servers, 
respectively. 
The Hypertext Transfer Protocol (HTTP) is one example of a method that 
implements hyperlinks and is probably the most widely used method for 
accessing the Internet today. A unique identifier, known as a Uniform 
Resource Locator (URL), specifies the location of a resource that can be 
accessed from the network. 
HTTP clients and HTTP servers typically communicate with one another using 
any one of a family of communication protocols known collectively as 
Transmission Control Protocol/Internet Protocol (TCP/IP). One commonly 
used member of the family, known as Transmission Control Protocol (TCP), 
provides for a very reliable delivery of an information stream. According 
to the TCP, a sender establishes a "connection" with a receiver, transmits 
an information stream in basic units known as packets, and retransmits any 
packets that are either lost or corrupted during transmission. One 
advantage of the TCP is that it guarantees the receiver will receive the 
bits and bytes in the information stream in the correct order. 
Unfortunately, the TCP requires considerable computing and network 
bandwidth resources. The establishment of a connection, for example, may 
require an exchange of more than ten packets between sender and receiver. 
In addition to the resources required to implement the TCP, the HTTP itself 
also requires considerable resources to format, process and display 
information. This is not a significant disadvantage in many situations 
because personal computers and other workstations with sufficient 
computing power, memory and display capabilities are readily available to 
implement the HTTP client function. 
There is, however, a growing interest to provide access to hypermedia 
servers connected to networks such as the Internet through mobile devices, 
particularly handheld devices like wireless telephones. These devices are 
characterized by severe limitations in processing power, memory space, 
display size, and buttons or keys by which a user can request, view and 
manipulate information obtained from a hypermedia server. Furthermore, the 
bandwidth of the communication channels connecting the mobile devices to 
the rest of the network is also severely limited. 
A wireless telephone has only a small fraction of the resources provided by 
a typical desktop or portable computer. Typically, the processing power is 
less than one percent of the processing power in many computers, the 
memory space is generally much less than 150 kilobytes (kB), and the 
display is perhaps four lines high and twelve or twenty characters wide. 
Graphics capabilities are very limited or nonexistent. The communication 
path is often in the range of 400 to 19,200 bits per sec. and the cost 
using that communication path is measured in terms of United States 
dollars per 100 kB or more. 
Attempts to implement HTTP client functions in portable devices have not 
been very successful. Attempts that have used mobile devices providing 
facilities which are comparable to conventional computers are unattractive 
because the cost of the device is very high. Other attempts using less 
expensive devices are also unattractive because the client functions are 
severely limited. In either case, the communication delays and costs in 
exchanging packets with the network just to establish a connection, for 
example, are intolerable. The delays are particularly annoying in 
situations where a user is notified that electronic mail or other 
information has been received in the user's "mail box" somewhere on the 
network and the user must wait during the roundtrip delay required to 
request and receive that mail from the mail box. The usability of the 
device is further impaired because there is insufficient memory space to 
store lists of frequently used hyperlinks. For HTTP clients, these 
hyperlink identifiers are URLs that are often difficult to remember and 
difficult to enter into the device due to limited data entry capabilities. 
Two popular software products used in conventional computers refer to 
these stored hyperlinks as "bookmarks" and "favorites." 
DISCLOSURE OF INVENTION 
It is an object of the present invention to provide structures and methods 
required by devices to interact with hypermedia servers connected to 
networks so that practical access to such servers is available to a wider 
range of devices such as wireless telephones. 
According to the teachings of the present invention in one embodiment of a 
system that comprises a remote device coupled to a directory server, the 
remote device is remotely located with respect to the directory server, 
comprises first storage, a display and a button, and executes a first 
program that causes the remote device to receive a unit of information 
from a hypermedia network, the unit of information having an identifier, 
and to present on the display a representation of the unit of information, 
to receive an input signal in response to the button being activated and, 
in response, to send an add request to the directory server that conveys 
the identifier, and the directory server comprises second storage that 
stores a directory associated with the remote device and executes a second 
program that causes the directory server to receive the add request and, 
in response, to add an entry to the directory representing the identifier. 
The various features of the present invention and its preferred embodiments 
may be better understood by referring to the following discussion and the 
accompanying drawing. The contents of the following discussion and the 
drawing are set forth as examples only and should not be understood to 
represent limitations upon the scope of the present invention.

MODES FOR CARRYING OUT THE INVENTION 
Overview 
The FIGURE illustrates a system in which various aspects of the present 
invention may be practiced. As will be explained below, some of the 
components illustrated in the FIGURE may be omitted in various 
embodiments. As shown, client 1 uses network 40 to access resources 
provided by server 51 and server 52. Although it is contemplated that 
server 51 and server 52 are hypermedia servers, perhaps operating in 
conformity with the Hypertext Transfer Protocol (HTTP), this is not 
necessary to practice the present invention. 
Client 1 comprises computer 31 and device 11, which is remotely located 
with respect to computer 31. Remote device 11 and computer 31 perform 
functions that implement client 1. Remote device 11 provides a user 
interface through which information can be presented to a user and input 
can be received from a user. Computer 31 exchanges information with 
network 40 in a manner that is consistent with a conventional network 
client. 
Computer 31 stores parameters and information in storage 32 that typically 
is a combination of random access memory (RAM, read-only memory (ROM) and 
long-term storage devices such as magnetic and optical disk drives. 
Computer 31 communicates with remote device 11 through receiver 21 and 
transmitter 22. Information that is sent by computer 31 through 
transmitter 22 is received by remote device 11 through receiver 16. 
Information that is sent by remote device 11 through transmitter 15 is 
received by computer 31 through receiver 21. 
In the embodiment shown in the FIGURE, remote device 11 comprises display 
12, one or more buttons 13, storage 14, transmitter 15 and receiver 16. 
For example, device 11 may be a wireless telephone such as a 
MobileAccess.TM. telephone by Mitsubishi Wireless Communications, Inc., or 
a Duette telephone by Samsung Electronics Corporation. In typical wireless 
telephones, the display 12 is a liquid crystal display (LCD) panel. 
Buttons 13 represent one or more data entry devices such as switches, keys 
or buttons. Storage 14 represents memory circuits or other devices that 
are capable of storing digital information. Preferably, at least part of 
storage 14 is persistent storage, meaning that information is retained 
when device 11 is turned off. In some embodiments, a portion of storage 14 
is organized into a unified push/pull cache. It is also contemplated that 
a portion of storage 14 will store program instructions, either in 
persistent memory or in ROM, and that device 11 will comprise a 
microprocessor or other type of processing circuitry capable of executing 
the program instructions. 
The nature of the communication paths shown between computer 31, server 51 
server 52, receiver 21 and transmitter 22 are not critical to the practice 
of the present invention. Such paths may be implemented as switched and/or 
non-switched paths using private and/or public facilities. Similarly, the 
topology of network 40 is not critical and may be implemented in a variety 
of ways including hierarchical and peer-to-peer networks. Computer 31 and 
server 51, for example, may be locally located with respect to one another 
and may be implemented on the same hardware. 
In concept, the nature of the communication paths between computer 31 and 
device 11 is also not critical to the practice of the present invention; 
however, in many applications device 11 is a wireless device that uses a 
communication technology such as electromagnetic transmission in the 
radio-frequency to infrared portions of the spectrum. In applications 
where device 11 is a wireless telephone, a cellular telephone for example, 
transmitter 15, receiver 16, receiver 21 and transmitter 22 represent 
communication facilities used for normal telephone calls. 
Examples of devices and methods that may be used to practice various 
aspects of the present invention are discussed below. The following 
discussion describes variations of a preferred embodiment that implements 
client 1 according to the HTTP; however, it should be understood that the 
present invention is not so limited. 
Remote Device 
In applications where client 1 is implemented as a HTTP client, device 11 
provides at least three basic functions. A navigation function allows a 
user to navigate or traverse HTTP Uniform Resource Locator (URL) 
hyperlinks. A communication function exchanges information with computer 
31. An interface function provides a user interface through which 
information may be presented to the user and through which input may be 
received from the user. 
Preferably, these finctions are implemented by a software-controlled 
process using an event-driven architecture. Events may be initiated by a 
user through buttons 13, for example, or may be initiated by signals 
received through receiver 16. The navigation function operates in either 
of two states. In the "ready" state the device awaits user input 
specifying a hyperlink to traverse. In the "pending" state the 
communication function has submitted a request to computer 31 and the 
device is waiting for a reply from computer 31. In terms of the HTTP, the 
ready state waits for user input specifying the URL of a hypermedia entity 
to display or process and the pending state waits for computer 31 to 
provide a requested hypermedia entity. 
In one embodiment, hypermedia information is exchanged with computer 31 
according to the Handheld Device Transfer Protocol (HDTP). A specification 
for a version of this protocol, sometimes referred to as Secure UPLink 
Gateway Protocol (SUGP), is provided in an Annex. The HDTP resembles the 
HTTP but is optimized for use with remote devices like wireless telephones 
and preferably is conveyed using the User Datagram Protocol/IP (UDP/IP). 
The UDP/IP is generally regarded as being less reliable than TCP/IP, for 
example, because it does not guarantee that packets will be received, nor 
does it guarantee that packets will be received in the same order that 
they are sent. Datagram protocols like the UDP/IP are attractive in 
practicing the present invention, however, because it does not require a 
"connection" to be established between a sender and a receiver before 
information can be exchanged. This eliminates the need to exchange a large 
number of packets during session creation. 
In a preferred embodiment, hypermedia information is organized according to 
a Handheld Device Markup Language (HDML) into cards and decks. Multiple 
decks and other types of message entities can be organized into 
information structures called digests. A specification for a version of 
HDML is provided in the Annex. 
A "deck" is the smallest unit of HDML information that can be exchanged 
with computer 31. Each deck has a unique identifier or URL. A user may 
navigate from one deck to another by traversing hyperlinks that reference 
the desired deck. If remote device 11 has a cache for received decks, the 
device first consults the cache to determine if the requested deck is 
available. Remote device 11 may also be implemented to determine if a 
desired deck found in cache is also current, that is, not out of date. If 
so, that deck is accessed without requiring any communication with 
computer 31. If the requested deck is not in the cache or is out of date, 
however, a request for that deck is sent to computer 31. This is discussed 
in more detail below. 
Because the display on remote device may be too small to show all the 
information in a deck at one time, each deck may be organized into one or 
more cards. A "card" is a unit of information that can be displayed and/or 
can define how a user may interact with the device. 
There are several types of cards. A "display" card conveys information that 
is to be displayed. An "entry" card conveys a method that permits a user 
to enter information and typically also conveys information to display. A 
"choice" card presents alternatives for selection by a user. Entry and 
choice cards also convey methods to be performed by device 11 that carry 
out functions necessary to receive input or recognize the chosen 
alternative. Typically, entry and choice cards cause one or more state 
variables to be set according to the information that is entered or the 
alternative that is chosen. A display card can also set one or more 
variables. A special form of the display card does not cause any visible 
display but can be used to set one or more variables. 
A "digest" is an optional information structure that may be used to 
facilitate the transmission and processing of multiple message entities 
including HDML decks. In particular, each message entity in a digest is 
processed in sequence according to entity type. In one embodiment, message 
entity types include HDML decks, images and alerts. One important use of 
the digest and the alert entity is discussed below. 
The current state of the three basic functions, navigation, communication 
and interface, can be expressed in terms of the deck and card in that deck 
that is currently displayed and one or more variables needed to process 
the card. By saving this information in persistent storage, remote device 
11 can restore the current state at a future time. A cache of decks, a 
navigation history of hyperlink traversals and a history of user activity 
can also be used to improve performance, provide additional functions to 
the user, and provide additional facilities for use by system developers. 
Handheld devices like telephones have severely limited facilities for 
entering information. The input facilities of these devices are often 
limited to the familiar twelve keys of a pushbutton telephone. One common 
method for entering text is to assign letters to various numeric keys 
according to normal telephone conventions. For example, the letters ABC 
are assigned to the "2" key and the letters DEF are assigned to the "3" 
key. The letters Q and Z could be assigned to the "0" key, for example. 
According to this method, the letter A is entered by pressing the "2" key 
once and the letter B is entered by pressing the key twice. In preferred 
embodiments of remote device 11, a form of letter prediction is used to 
make text entry more efficient. 
This prediction can be based on the statistics of letter combinations. For 
example, after entering the letters T and H, it is much more likely that a 
user will enter the letter E than the letters D or F. Accordingly, after 
entering T and H, in response to a user pressing the "3" key, remote 
device 11 will present the letter E first rather than the letter D. The 
prediction can be based on a table of probabilities for various 
three-letter combinations stored in storage 14. 
Intermediate Computer 
Computer 31, together with remote device 11, provides the functions of a 
conventional hypermedia client. In the embodiment discussed above, 
computer 31 receives information from remote device 11 according to the 
HDTP, translates the HDTP information into corresponding HTTP information 
as necessary, and sends the result to server 51. Similarly, computer 31 
receives information from server 51 according to the HTTP, translates the 
HTTP information into corresponding HDTP information as necessary, and 
sends the result to remote device 11. Preferably, HDTP information 
exchanged with remote device 11 is compiled from a textual form into a 
binary form that reduces the bandwidth requirements of the communication 
channel and reduces the processing required by remote device 11 to parse 
and interpret the information. Alternatively or in addition, the 
information may be subjected to other types of data compression to reduce 
bandwidth requirements. 
Basic Exchange of Messages 
By using the UDP/IP, a session can be created more efficiently than is 
possible using the more common TCP/IP. The exchange of information needed 
to create a session is similar to the exchange carried out for other types 
of requests. An exchange can be initiated by remote device 11 sending a 
request to computer 31. Subsequently, computer 31 returns a reply to the 
request and remote device 11 acknowledges receipt of the reply. The reply 
may either be expected results of the request or it may be an indication 
of some error encountered while attempting to service the request. If 
remote device 11 does not receive a reply within some timeout interval, it 
will send the request to computer 31 again. Remote device 11 will send the 
request repeatedly until either it receives a reply message, or a standby 
or "HoldOn" message from computer 31. The length of the timeout interval 
can be user configurable or it can be established by information 
previously received from computer 031. Similarly, computer 31 will send 
the reply repeatedly until it receives the acknowledgement from remote 
device 11. 
For example, remote device 11 may initiate the creation of a session by 
sending a session-creation request to computer 31. The request includes 
any necessary authentication information, one or more session parameters, 
and information describing the device and version of software in use. 
Computer 31 receives the request, validates the authentication 
information, checks that the user is entitled to initiate a session, 
assigns an identifier to the new session, builds a message containing the 
session identifier and any information that computer 31 wishes to pass to 
remote device 11, and sends the message to remote device 11. Preferably, 
this message also includes the URL of a "home page" associated with the 
device. Remote device 11 acknowledges receipt of the message and the 
session is established. 
Get Request 
As another example, when a user traverses a hyperlink, remote device 11 
consults its cache, if any, and determines if the cache already has the 
requested hypermedia entity (HDTP deck). If it does and the deck in the 
cache is not out of date, remote device 11 can process the requested deck 
and no further action is required. If the requested deck is not available 
or is out of date, however, remote device 11 builds a message including a 
HDTP "Service Request" and the URL of the requested deck and sends the 
message to computer 31. According to the HDTP, the message also includes a 
header with information that is unique to the request. Remote device 11 
then waits for a reply from computer 31. The reply may be the requested 
deck or it may be an indication that an error occurred while attempting to 
service the request. 
Computer 31 receives the request, checks its validity and attempts to 
establish a connection with the appropriate network server, say server 51. 
If the connection fails, remote device 11 is notified. Otherwise, computer 
31 builds a message that includes a HTTP "GET" method and the URL of the 
desired hypermedia entity. In one embodiment, the header of the message is 
constructed from "common" parameters that are common to all users, from 
"session" parameters that are unique to the session with remote device 11, 
and any "request" parameters that were passed in the header of the HDTP 
request. Preferably, any conflicts in the three sets of parameters are 
resolved in favor of request parameters first, session parameters second, 
and common parameters last. Alternatively, the HTTP header may be 
constructed from just common parameters, just session parameters, just 
request parameters, or any combination of these parameters. 
After constructing the HTTP get request, computer 31 sends it through the 
established connection to server 51. Server 51 attempts to service the 
HTTP "GET" request and sends the result to computer 31 in a HTTP response. 
Computer 31 checks a result code contained in the header of the HTTP 
response. If the result code indicates an error occurred, computer 31 may 
take any of several possible actions explained below. If the result code 
indicates the request was serviced successfully, computer 31 builds an 
appropriate HDTP response containing the results of the get request and 
sends the HDTP response to remote device 11. Computer 31 may compress, 
encrypt or convert the result as desired. If server 51 does not respond 
with a complete result within a reasonable period of time, the connection 
is dropped and an error indication is returned to remote device 11. 
Remote device 11 acknowledges receipt of the HDTP response and displays 
and/or processes message entities included in the response. If computer 31 
does not receive an acknowledgement within a reasonable period of time, it 
sends the HDTP response again. Computer 31 may repeat the transmission one 
or more times until an acknowledgment is received. If an acknowledgement 
is not received after a desired number of attempts, computer 31 may 
discard the result and abandon the attempt to send it, save the result in 
storage 32 for a future attempt, or save a message for future transmission 
indicating the result was discarded. 
Variations on the Get Request 
Computer 31 may respond with error indications for a variety of 
circumstances. For example, computer 31 may notify remote device 11 that 
the requested URL is for a scheme or protocol that is not supported, or 
that the requested URL designates a network server that cannot be resolved 
using the Domain Name Service (DNS). 
HTTP result codes are numerical codes of the form XXX. If the result code 
in a HTTP response is 301 or 302, a "redirection error," it indicates the 
requested resource has been moved. The new URL may be returned to remote 
device 11. Alternatively, computer 31 may respond to the redirection error 
by using the new URL to establish a connection with the new server, say 
server 52, construct a new HTTP get request and submit it to server 52. 
The response from server 52 and the new URL are returned to remote device 
11. 
If the result code in a HTTP response is 401, it indicates the user is not 
authorized access to a particular "realm." Computer 31 may check storage 
32 to determine if there is a user name and password for the realm that 
generated the error. If an appropriate user name and password are 
available, computer 31 can resubmit the request with the authorizing 
information. If a user name and password are not available, or if the 
resubmitted request results in a another unauthorized error, computer 31 
may construct a HDTP deck with an entry card by which the user can enter 
the correct user name and password for the realm generating the error. 
Generally client errors (4xx), server errors (5xx) and other types of 
errors may be handled by computer 31 returning a deck with one or more 
display cards explaining the nature of the error and what course of action 
the user may consider taking. 
Additional Functions and Features 
Remote device 11 can use a post request to send data to a server. In one 
embodiment, remote device 11 builds a HDTP "Post" request including the 
URL of the intended network server and a block of data. Computer 31 
constructs and sends a corresponding HTTP "POST" method in a manner 
similar to that described above for the get request. 
Although many client functions do not need to be implemented to realize the 
benefits of the present invention, some client functions are important in 
many applications. These functions include creating and managing sessions 
with a hypermedia server, handling a variety of error conditions like 
those discussed above, authenticating a user to the server, establishing a 
private session and managing user certificates and encryption keys, 
managing a first level cache, handling redirection errors and validating 
hypermedia content. 
The operational characteristics of client 1 are affected by parameters and 
other information stored in storage 32. Examples of operational 
characteristics include a list of authorized subscribers or users, 
resources that are available to each respective user, and timeout values 
for respective remote devices 11 and computer 31. In preferred 
embodiments, these parameters and information are maintained by a facility 
on computer 31 that operates as a network server, perhaps a HTTP server. 
In this manner, the operational characteristics of client 1 can be 
administered locally or remotely by an authorized network client. 
The headers for each HTTP request can include a parameter that specifies 
what type of content for the response is acceptable. As mentioned above, 
in some embodiments this parameter can be obtained from common parameters, 
session parameters or request parameters. Computer 31 can check the 
content of any reply from a server and determine whether the content is 
acceptable to remote device 11. If the content is not acceptable, computer 
31 may notify remote device 11 of the error. For example, content types 
such as applets, movies and certain types of images may not be acceptable. 
Alternatively, when possible, computer 31 may convert the content into a 
form that is acceptable. For example, computer 31 may be able to convert 
one type of image, say JPEG, into an acceptable form, say GIF. 
Remote Device Initialization 
An HDTP session can have a very long life, extending beyond the time remote 
device 11 is turned off. A session can also be interrupted by some other 
function remote device 11 is required to perform such as, for example, a 
wireless telephone initiating or receiving a voice telephone call. Remote 
device 11 can resume a suspended session with computer 31 by preserving 
session-related information in persistent storage. This information 
includes the session identifier and any information required to identify 
computer 31. In addition, if encryption has been in use for this session, 
the saved information can include encryption keys, flags indicating the 
type of encryption method, block-chaining values, or other information 
needed to resume encryption. Alternatively, encryption can be initiated 
anew as is done at time of session creation. 
In an embodiment allowing resumption of a suspended session, remote device 
11, when turned on, determines whether a session was suspended. If it was, 
remote device 11 sends a request to computer 31 using the session-related 
information stored in persistent storage. Computer 31 receives the 
request, validates the session and determines whether the session has 
expired. If the session is valid, computer 31 services the request. If the 
session is not valid, computer 31 returns an error indication to remote 
device 11 which can then initiate a request to create a new session. 
At the time of session creation, remote device 11 establishes session 
parameters used to construct HDTP headers. These parameters can be set 
according to values provided by remote device 11 and/or computer 31. These 
parameters may include HTTP related values such as Accept, Accept-Charset 
and Accept-Language, and they may include values not related to the HTTP 
such as a timeout interval between sending retries, maximum packet length 
remote device 11 can accept and the encryption algorithm to use. 
Preferably, in subsequent exchanges between remote device 11 and computer 
31 after these parameters are established, headers include only parameters 
that the receiving device does not already know. 
Preferably, headers are formed in a manner that simplifies the processing 
required to parse and interpret the embedded information. Headers for the 
HDTP contain pairs of ASCII text strings, each string terminated by a null 
or zero-valued byte. The first string in each pair specifies a key or 
parameter name and the second string provides the key's value. Most 
headers contain a single byte that specifies the header type. Frequently 
used keys and values can be encoded into single bytes having a value from 
128 to 255. 
In preferred embodiments, remote device 11 also checks during 
initialization for anything relevant that is pending in computer 31. For 
example, responses or message entities may have queued up in computer 31 
while the session with remote device 11 was suspended. 
Most practical implementations of remote device 11 do not maintain accurate 
time. In preferred embodiments, during initialization or at any time 
thereafter, remote device 11 can obtain the current time from computer 31 
by a request. 
Reducing Perceived Latency 
Various network services including electronic mail have the ability to 
notify a user when some asynchronous or unsolicited event has occurred or 
is about to occur. In this context, the term "unsolicited" refers to an 
event that is not a direct result of some user request. A notification of 
the arrival of one or more pieces of electronic mail or data from other 
users or from services providing periodic stock price quotations are 
examples of unsolicited events. In response to the notification, a user 
can request delivery of the mail, the data, or some other message from the 
network server that provided the notification. Referring to the FIGURE, 
the network service providing the notification may reside on server 51, 
for example, or it may reside on computer 31. 
The time required to obtain the unsolicited information is at least as 
great as the total time it takes to convey the request to the server and 
to convey the reply from the server to the user's terminal or workstation. 
In conventional systems, the communication time is usually not a factor; 
however, as mentioned above, signal propagation time between remote device 
11 and computer 31 can be significant in systems where the communication 
path has a low bandwidth. For example, data communication via wireless 
telephones is sometimes restricted to as little as a few hundred bits per 
sec. 
Significantly, the primary source of user dissatisfaction in such 
applications is how much time is spent waiting for return of the reply, 
not when the reply actually arrives. For example, if electronic mail were 
to arrive in a user mail box at 3:00 p.m., most users would not be 
concerned whether the mail reached their terminal at 3:02 p.m. or 3:05 
p.m. What is of concern, however, is the perceived delay, the time spent 
waiting for requested information to arrive. The perceived delay can be 
greatly reduced by delivering at least a portion of the unsolicited 
information to remote device 11 before notifying the user. 
In one embodiment, a network service receives messages representing one or 
more instances of unsolicited information for remote device 11. That 
network service causes computer 31 to generate one or more message 
entities representing at least a portion of the unsolicited information 
and to send those message entities to remote device 11. Preferably, the 
message entities are assembled into one or more HDML decks that are 
contained in a digest. Also included in the digest is a message entity 
that specifies an operation, or type of operation, that remote device 11 
is to perform to notify the user. The notification may be a visual 
presentation on screen 12, or it may be an aural or tactile presentation 
by some other suitable transducer. The notification may also be 
accompanied by text, presented on display 12, explaining the nature of the 
notification. The message entity specifying the notification can also 
contain the URL of any related hypermedia entity such as the fulltext of 
electronic mail, embedded files, an "entry" card for preparing an 
immediate reply, etc. 
In electronic mail applications, the digest preferably includes cards 
representing a portion of each piece of mail, say the first 100 
characters, one or more cards containing a list of all mail in the user's 
mail box, and a card with one or more URLs that causes the network service 
to deliver the text of one or more messages. Remote device 11 should 
process the cards, decks and other message entities included in the digest 
in strict order. Significantly, the notification or alert message entity 
should be processed after the preceding message entities have been stored 
in storage 14 and are available for display or other processing. 
In practice, notification or alert message entities are often used with 
"prefetch notifications." Prefetch notifications specify a deck or digest 
which an application executing in remote device 11 requests and stores in 
storage 14 before notifying a user. 
In preferred embodiments of remote device 11, notification or alert message 
entities are stored in persistent storage and a card is provided that 
displays a list of alert message entities that have been sent to remote 
device 11. An indication of whether a user has acted on a notification is 
stored and displayed for each respective alert message entity. When a new 
alert message entity arrives, remote device 11 determines if a duplicate 
entity is already stored. If a duplicate entity is stored, the older 
entity is deleted and the new entity is stored, clearing any indication 
that the user has acted on the corresponding notification. 
Saving Lists of Bookmarks 
In devices like wireless telephones, there is usually insufficient storage 
to save lists of frequently used hypermedia links, e.g., URLs. This 
limitation reduces the usefulness of these devices because hypermedia 
links are usually difficult to remember and especially difficult to enter 
into the device. Software products for conventional computers provide 
facilities to save lists of these links. Two popular products refer to 
these stored links as "bookmarks" and "favorites." 
This limitation is overcome by storing designated hypermedia links or 
bookmarks on a network server, referred to herein as a bookmark server. In 
one embodiment, the URL of this server is sent to remote device 11 during 
initialization of the device. 
In response to the activation of a particular button 13, remote device 11 
uses the bookmark server URL to construct a request to save the bookmark 
of the deck containing the currently displayed card. This may be done by 
appending the bookmark server URL with an argument specifying the deck 
bookmark and submitting the request to computer 31. Computer 31 passes the 
request to the bookmark server. The bookmark server services the request 
by saving the bookmark specified in the argument in a list uniquely 
associated with remote device 11. In addition, an entry card can be used 
to prompt the user for a name or description of the bookmark. The name and 
bookmark UiRL are sent to the bookmark server which saves the bookmark and 
accompanying name in the list. Preferably, the bookmark server can also 
store one or more state variables used by remote device 11 to display or 
process the associated deck. For example, a state variable may be used to 
save information that a user entered through an entry card. These state 
variables can be conveyed to the bookmark server by additional arguments 
appended to the server URL. 
In preferred embodiments, decks and specified cards within decks may 
contain indications that they cannot be bookmarked. If a user attempts to 
save a bookmark for such a card or for any card with such a deck, remote 
device 11 is caused to display an appropriate message informing the user 
that the current card cannot be marked. 
Remote device 11 can request all or part of the stored list by sending an 
appropriate request to the bookmark server. In one embodiment, the request 
comprises the URL of the bookmark server appended with an argument 
specifying the first entry in the list to send. For example, an initial 
request would specify the first entry in the list. In reply, the bookmark 
server would build a response representing entries one through N and a 
value referencing entry number N+1. A subsequent retrieval request from 
remote device 11 would include the URL of the bookmark server appended 
with an argument specifying the N+1 entry. By continuing in this manner, 
the user is able to retrieve and display all entries in the stored list of 
bookmarks. 
The deck and cards in the reply received from the bookmark server can also 
contain methods for modifying or deleting bookmarks in the stored list. A 
request to modify a bookmark can be made by appending the bookmark server 
URL with arguments specifying a change to the selected bookmark and the 
desired change. Similarly, a request to delete a bookmark can be made by 
appending the bookmark server URL with arguments specifying a deletion of 
the selected bookmark. 
By implementing the bookmark server as a standard HTTP server, the bookmark 
list for a user can be accessed and maintained by any standard HTTP 
client. This feature allows a user to setup and maintain the list more 
easily using a conventional computer. 
Annex and Incorporated Documents 
Documents in an Annex to this main disclosure, computer listings in the 
microfiche appendix, and documents incorporated herein by reference, 
include specifications, proposals, specific implementations and features 
of particular products that describe and embody various aspects of the 
present invention. Terms such as "required," "must," "significant," 
"necessary," "minimum" and "maximum" refer to particular embodiments 
disclosed therein and do not represent limitations on the scope of the 
present invention. Because these documents describe several versions of 
specific products, specifications and proposals, some features and 
terminology may differ among the several documents and this main 
disclosure. Not all features described therein are required to practice 
the present invention; the various features may be used in essentially any 
combination. These documents describe some features that are either 
omitted or are not discussed in as much detail in this main disclosure. To 
this extent, these documents augment the main disclosure. To the extent 
that these documents disclose or suggest limitations that are not 
described in the main disclosure, those inconsistencies are to be resolved 
in favor of the main disclosure.