[ DESCRIPTION]
[ Title]
INFORMATION PROCESSING SYSTEM
[ Technical Field]
[ 0001]
The present invention relates to an information
processing system for managing sessions each offering a
service in which at least one user can participate, a
server system and a client device making up such an
information processing system, a control method for such
a client device, a program for controlling such a client
device, and an information storage medium storing such a
program.
[ Background Art]
[ 0002]
There are services that users can use and participate in
via a network, such as chat and multiplayer games.. Such
services offer a plurality of sessions each possibly
participated in by different users like chat rooms. These
sessions provide their services independently of one
another. Each user participates in one of a plurality of
sessions and uses the service provided by the session.
[ 0003]
A user participating in a session may want another user
such as his/her friend to take part in the same session.

Service providers may also wish to invite specific or
indefinite users to participate in a service they provide.
Such a service may involve offering the function of
inviting users to the session by sending out a session
invitation message, for example.
[ Summary]
[ Technical Problem]
[ 0004]
The sessions above may not exist permanently; they are
generated anew as needed. A session may be controlled to
end when the users participating in it stop using the
service provided by the session. In this case, individual
sessions are generated anew as requested by users who
wish to use the services provided by the sessions. The
session is ended when there are no participants or when
the user who requested generation of that session orders
it to end, for example. Thus when a user (invited user)
has been invited to participate in a session, the session,
which was valid at the time of invitation, may have ended
by the time the invited user accepts the invitation and
tries to participate in the session. In this case, the
invited user has no way to know whether the session has
already ended or not until the user actually makes a
request to participate in the session he/she has been
invited to. This is an inconvenience for the invited user.

[ 0005]
The present invention has been made in view of the above
circumstances-. An object of the invention is to provide
an information processing system for allowing an invited
user invited to a session to know whether the session is
still valid or not before the invited user particulates
in the session, a server system and a client device
making up such an information processing system, a
control method for such a client device, a program for
controlling such a client device,and an information
storage medium storing such a program.
[ Solution to Problem]
[ 0006]
According to the present invention, there is provided an
information processing system including a plurality of
client devices and managing information about a plurality
of sessions each offering a service possibly participated
in by a user. The information processing system includes:
a session managing section configured to store status
information indicating whether each of the plurality of
sessions is valid or not; and an invitation managing
section configured to store a plurality of items of
invitation information, each of the items of invitation
information being about an invitation for an invited user
to participate in one of the plurality of sessions. Each

of plurality of the client devices includes: an
invitation information acquiring section configured to
acquire one of the plurality of items of invitation
information stored in the invitation managing section,
the acquired item of invitation information being about
the invitation for the user using the client device to
become the invited user; and an invitation display
controlling section configured to display on a display
screen the item of invitation information acquired by the
invitation information acquiring section in a manner
reflecting the status information.
[ 0007]
According to the present invention, there is provided a
server system connected to a plurality of client devices
and managing information about a plurality of sessions
each offering a service possibly participated in by a
user. The server system includes: a session managing
section configured to store status information indicating
whether each of the plurality of sessions is valid or
not; an invitation managing section configured to store a
plurality of items of invitation information, each of the
items of invitation information being about an invitation
for an invited user to participate in one of the
plurality of sessions; an invitation information offering
section configured to offer, when requested by one of the

plurality of client devices, one of the plurality of
items of invitation information stored in the invitation
managing section, the offered item of invitation
information being about the invitation for the user using
the requesting client device to become the invited user;
and a status information offering section configured to
offer to the requesting client device the status
information stored in the session managing section
regarding the session targeted for invitation by the
offered item of invitation information. The offered
status information is used when the client device
displays the offered item of invitation information on a
display screen.
[ 0008]
According to the present invention, there is provided a
client device connected to a session managing section
configured to store status information indicating whether
each of a plurality of sessions offering a service
possibly participated in by a user is valid or not; and
an invitation managing section configured to store a
plurality of items of invitation information, each of the
items of invitation information being about an invitation
for an invited user to participate in one of the
plurality of sessions. The client device includes: an
invitation information acquiring section configured to

acquire one of the plurality of items of invitation
information stored in the invitation managing section,
the acquired item of invitation information being about
the invitation for the user using the client device to
become the invited user; and an invitation display
controlling section configured to display on a display
screen the item of invitation information acquired by the
invitation information acquiring section in a manner
reflecting the status information.
[0009]
According to the present invention, there is provided a
control method for a client device connected to a session
managing section configured to store status information
indicating whether each of a plurality of sessions
offering a service possibly participated in by a user is
valid or not; and an invitation managing section
configured to store a plurality of items of invitation
information, each of the items of invitation information
being about an invitation for an invited user to
participate in one of the plurality of sessions. The
control method includes: a step of acquiring one of the
plurality of items of invitation information stored in
the invitation managing section, the acquired item of
invitation information being about the invitation for the
user using the client device to become the invited user;

and a step of displaying on a display screen the acquired
item of invitation information in a manner reflecting the
status information.
[0010]
According to the present invention, there is provided a
program for controlling a client device connected to a
session managing section configured to store status
information indicating whether each of a plurality of
sessions offering a service possibly participated in by a
user is valid or not; and an invitation managing section
configured to store a plurality of items of invitation
information, each of the items of invitation information
being about an invitation for an invited user to
participate in one of the plurality of sessions. The
program causes the client terminal to execute: a step of
acquiring one of the plurality of items of invitation
information stored in the invitation managing section,
the acquired item of invitation information being about
the invitation for the user using the client device to
become the invited user; and a step of displaying on a
display screen the acquired item of invitation
information in a manner reflecting the status information.
Preferably, this program is stored on a computer-readable
information storage medium.
[ Brief Description of Drawings]

[ 0011]
[ FIG. 1]
FIG. 1 is an overall configuration diagram of an
information processing system in one embodiment of the
present invention.
[ FIG. 2]
FIG. 2 is a structural block diagram of a client device
in one embodiment of the present invention.
[ FIG. 3]
FIG. 3 is a schematic diagram showing an exemplary flow
of processing performed when the information processing
system in one embodiment generates a session.
[ FIG. 4]
FIG. 4 is a schematic diagram showing an exemplary flow
of processing performed when the invitation is extended
from the inviting user to the invited user.
[ FIG. 5]
FIG. 5 is a schematic diagram showing an exemplary screen
displaying a list of invitations.
[ FIG. 6]
FIG. 6 is a schematic diagram showing an exemplary
detailed display screen of invitation information.
[ Description of Embodiments]
[ 0012]
Some embodiments of the present invention are described

below in detail with reference to the accompanying
drawings.
[0013]
FIG. 1 is an overall configuration diagram of an
information processing system 1 in one embodiment of the
present invention. As shown in FIG. 1, the information
processing system 1 is structured to include a plurality
of client devices 2, a service offering server 3, a
session managing server 4, an invitation managing server
5, a notification server 6, and a client managing server
7. In this embodiment, the information processing system
1 is assumed to be a game system that offers a
multiplayer game-playing environment to users. The
service offering server 3 generates a session offering a
game service to participants. A session is a unit in
which the system offers its services. In the multiplayer
game service, a lobby or a room corresponds to a session,
for example. A plurality of users participating
concurrently in the same session play the same game by
fighting against each other or by cooperating with each
other. However, users participating in different sessions
in the same type of game play different games
independently of one another. Although FIG. 1 shows only
one service offering server 3, there may be a plurality
of service offering servers 3 that may offer game

services differing from one another in type. Also, the
service offering server 3 may be provided by a game
vendor different from the vendor that offers a service
infrastructure of the information processing system 1 by
setting up the session managing server 4, invitation
managing server 5, notification server 6, and client
managing server 7.
[ 0014]
The client device 2 is a terminal device used by the user
who participates in a session generated by the
information processing system 1 and who uses the service
offered by the session. For example, the client device 2
is a home video game console, a handheld video game
machine, a smartphone, a personal computer, or some other
information processing device. As shown in FIG. 2, each
client device 2 is structured to include a control
section 11, a storage section 12, and a communication
section 13. Also, an operation device 14 and a display
device 15 are connected to each client device 2.
[0015]
The control section 11 is a central processing unit (CPU)
or like unit that performs diverse kinds of information
processing in accordance with programs stored in the
storage section 12. The storage section 12 is structured
to include a memory device such as a random access memory

(RAM) that stores the programs executed by the control
section 11 as well as data targeted for processing by the
programs.
[ 0016]
The communication section 13 is a communication interface
such as a local area network (LAN) card. Through the
communication section 13, the client device 2 performs
data communication with each of the service offering
server 3, session managing server 4, invitation managing
server 5, and notification server 6.
[ 0017)
The operation device 14 is a game console controller, a
keyboard, or a mouse, for example. The operation device
14 receives the input of operations made by the user and
outputs the content of the received input to the client
device 2. The display device 15 is a liquid crystal
display or an organic electroluminescent (EL) display,
for example. The display device 15 displays on a display
screen the image corresponding to a video signal output
from the client device 2. Incidentally, the operation
device 14 and the display device 15 may each be provided
independently of the housing of the client device 2, or
may be incorporated integrally in the housing of the
client device 2.
[ 0018]

The storage section 12 of the client device 2 stores
system software (basic software) 21 and game programs 22.
These programs are executed by the control section 11.
The system software 21 is a program that offers basic
functions needed in using this system regardless of the
game type. The game programs 22 are application programs
to be executed by the client device 2 in using the
services offered by the service offering server 3. Each
of the game programs 22 is prepared for each game type.
The user needs to obtain beforehand the game program 22
corresponding to the session in which the user plans to
participate and, while participating in the session,
needs to have the game program 22 executed by the client
device 2. These programs may be stored on a computer-
readable information storage medium such as an optical
disk or downloaded via communication lines such as the
Internet when offered to the client device 2.
[ 0019]
The service offering server 3 generates a new session in
accordance with session start request from one of the
client devices 2 and performs game processing on the
generated session. The service offering server 3 may
generate a plurality of sessions that carry out processes
independently of one another regarding games. Each
session receives a participation request from the user of

the client device 2. The session transmits the result of
the executing game process to each client device 2 used
by the user participating in the session, thus offering
the game service to the participating user. This allows a
plurality of users participating in the same session to
play a multiplayer game together by fighting against each
other or by cooperating with each other.
[ 0020]
The session managing server 4 manages information about
the sessions generated by the service offering server 3.
The information held in and specific processes performed
by the session managing server 4 will be discussed later.
[ 0021]
The invitation managing server 5 manages invitations
extended between users. In this embodiment, any user
participating in a session may invite another user to
participate in the same session. The information about
the invitations is managed by the invitation managing
server 5 and is referenced by the client device 2. The
information held in and specific processes performed by
the invitation managing server 5 will be discussed later.
[ 0022]
The notification server 6 maintains network connections
with the client devices 2 currently using the services
offered by this system and, in response to requests from

other servers, gives various notifications such as
invitation messages to the client devices 2. Specifically,
when a user starts up his/her client device 2 and logs in
to a service of this system, a network connection is
established between the client device 2 and the
notification server 6. While the client device 2 is using
the service, the notification server 6 maintains the
network connection with the client device 2. When the
user is to be notified of an invitation message, for
example, the notification server 6 uses the maintained
network connection to give a push notification to the
client device 2. In this manner, the user may be notified
of diverse information in real time.
[ 0023]
The client managing server 7 manages online status of
each client device 2. Specifically, when the notification
server 6 establishes a network connection with a client
device 2, the notification server 6 notifies the client
managing server 7 that the client device 2 is currently
online. Given the notification, the client managing
server 7 adds information about the newly connected
client device 2 to a list of currently online client
devices 2 (online client list). When the user of the
client device 2 stops using the service and logs out, the
network connection between the notification server 6 and

the client device 2 is disconnected. The notification
server 6 then notifies the client managing server 7 that
the client device 2 is currently offline. Upon receipt of
the notification, the client managing server 7 deletes
the information about the offline client device 2 from
the online client list. If the communication connection
with a client device 2 that has been online so far is
disconnected due to some error and is not reestablished
within a predetermined time period, the notification
server 6 determines that the client device 2 is currently
offline and notifies the client managing server 7 to that
effect. This allows the client managing server 7 to
manage in real time which client devices 2 are currently
online. In addition to the online status of the client
devices 2, the client managing server 7 may manage other
information acquired from each client device 2 such as
the type of the game program 22 currently executed by
that client device 2.
[ 0024]
Explained below with reference to the flowchart of FIG. 3
is a specific flow of processing performed by the
information processing system 1 of this embodiment when a
session is generated.
[ 0025]
A client device 2 used by a user executes a game program

22 to transmit a session generation request to the
service offering server 3 that offers the game
corresponding to the executing game program 22 (step S1).
In the ensuing description, the user making the session
generation request will be referred to as the host user,
and the client device 2 used by the host user to transmit
the session generation request will be referred to as the
host device. On receiving the session generation request
from the host device, the service offering server 3
generates a new session and gives it identification
information so as to identify the newly generated session
within the service offering server 3 (step S2). For
distinction from a session identification (ID) (to be
discussed later) given to a session by the session
managing server 4, the session identification information
given to each session generated by the service offering
server 3 will be referred to as the service ID in the
description that follows. Upon giving the service ID to
the session, the service offering server 3 notifies the
client device 2 of that service ID (step S3).
[ 0026]
Given the notification in step S3, the host device
transmits to the session managing server 4 a registration
request to register information about the session
generated in step S2 (step S4). The registration request

includes information identifying the service offering
server 3 that has generated the session, and the service
ID given to the session by the service offering server 3.
Upon receiving the registration request, the session
managing server 4 issues a session ID to the session
targeted for registration by the registration request and
notifies the host device of the issued session ID (step
S5) . Unlike the service ID given by the service offering
server 3 in step S2, the session ID is a value that
uniquely identifies the session in the entire system.
When notified of the session ID, the host device notifies
the session managing server 4 of diverse items of
information regarding the session to be registered in the
session managing server 4 (step S6). On receiving the
information in step S6, the session managing server 4
registers the received information in a database the
session managing server 4 manages (step S7).
[ 0027]
What follows is a description of the information about
the session registered in step S7 and managed by the
session managing server 4. With regard to each session
generated by the service offering server 3, the session
managing server 4 stores as session-related information
such related items of information as a session ID,
session reference destination information, a session name,

a session image, accessory information, device type
information, a public flag, a game title name, a
participant list, a host user ID, a session generation
time, and a validity flag. The session ID is information
that identifies each session within the session managing
server 4. As described above, the session ID is issued by
the session managing server 4 when the information about
a new session is registered in the session managing
server 4. The session reference destination information
is information that identifies the source offering the
service with regard to the session. For example, the
session reference destination information may include
address information of the service offering server 3 and
a service ID. In this case, the host device notifies the
session managing server 4 of the address information and
the service ID in step S4 as described above.
[ 0028]
The session name is the name of this session. The session
image and the accessory information make up information
regarding the content and status of the game played in
the session. The session image may be image data
representative of a play screen of the session, for
example. The accessory information such as a stage name
is used to inform the user of the content and status of
the session.

[ 0029]
The device type information is information indicative of
the device type of the client device 2 allowed to
participate in the session. Different types of games can
be played selectively on different types of participating
client devices 2. For example, some games can be played
only on a particular home video game console; others may
be played on any of the home video game console, handheld
video game machine, and personal computer. The device
type information stipulates the type of the client device
2 allowed to participate in the session. The public flag
is flag information indicating whether or not the
information regarding this session has been made public
to indefinite users. Anyone can reference the content of
the session for which the public flag is set to on; any
user may request to participate in that session. In
contrast, only invited users are allowed to reference the
information about the session for which the public flag
is set to off and to participate in the session. The
content of the session name, session image, accessory
information, device type information, and public flag is
determined by the game program 22 of the host device or
by the service offering server 3, before being
transmitted to the session managing server 4 by the
system software 21 in step S6. Alternatively, the content

of the session image and accessory information may be
updated in a suitably timed manner in accordance with the
situation change of the session to reflect the
information offered by the service offering server 3 to
the session managing server 4.
[ 0030]
The game title name is information that identifies the
type of the game (i.e., game title) offered by the
session. When notifying the session managing server 4 of
the session information, the system software 21 of the
host device acquires the name of the currently executing
game program 22 as the information representing the game
title name.
[ 0031]
The participant list is a list of users participating in
the session. If the client device 2 used by a user other
than the host user participates anew in the currently
executing session, the client device 2 notifies the
session managing server 4 to that effect. Given the
notification, the session managing server 4 adds the user
ID of the newly participating user to the participant
list. When a user has stopped participating in the
session, the client device 2 used by that user notifies
the session managing server 4 of the end of the
participation. Upon receipt of the notification, the

session managing server 4 deletes from the participant
list the user ID of the user who has stopped
participating. When any client device 2 goes offline, the
client managing server 7 notifies the session managing
server 4 to that effect. Given the notification, the
session managing server 4 searches for the session
participated in by the user of the applicable client
device 2 and deletes the user ID of that user from the
participant list of the session. This enables the
information about the offline user to be deleted from the
participant list even if his/her client device 2 fails to
normally complete the process of ending the participation
in the session.
[ 0032]
The host user ID is information that identifies the host
user who has requested the generation of the session. The
session generation time is information indicative of the
time at which the session was generated. When the session
managing server 4 registers the information about a new
session, date and time information at that point in time
is recorded as the session generation time.
[0033]
The validity flag is flag information indicating whether
the session is valid or invalid. When the session
managing server 4 registers the information about a new

session, the value indicating the validity of the session
is set to validity flag. At the end of the session, the
client device 2 that initiated the end of the session
notifies the session managing server 4 of the session end.
Given the notification, the session managing server 4
sets to invalid the validity flag of the session targeted
by the notification. For example, the condition for
ending the session is met by the host user having stopped
participating in the session. In that case, the host
device notifies the session managing server 4 of the end
of the session. Alternatively, the service offering
server 3 may end the session when there is no participant
in the session. In this case, the client device 2 used by
the user who has most recently stopped participating in
the session notifies the session managing server 4 of the
session end. Whereas the client device 2 notifies the
session managing server 4 of the start and the end of the
session in this example, this is not limitative of the
embodiment. Alternatively, the service offering server 3
may notify the session managing server 4 of the start and
the end of the session. As another alternative, part or
all of the information offered to the session managing
server 4 by the client device 2 may be offered to the
session managing server 4 not by the client device 2 but
by the service offering server 3.

[ 0034]
As explained above, the session managing server 4 manages
the information about sessions independently of the
service offering server 3 that actually generates the
sessions and performs processing on the generated
sessions. In particular, the information about each
session includes the validity flag that is updated in
real time whenever a session is actually started or ended.
Each client device 2 can thus determine whether a
specific session is valid or invalid by referencing the
validity flag held by the session managing server 4
without gaining access to the service offering server 3,
as will be discussed later. The service offering server 3
is prepared for each game type. Each service offering
server 3 is assumed to be accessed by the corresponding
game program 22. To access the service offering server 3,
the client device 2 needs to execute the corresponding
game program 22. However, this embodiment allows the
running system software 21 to acquire the information
about the session from the session managing server 4
without executing the game program 22.
[ 0035]
Specifically, the system software 21 of each client
device 2 acquires a list of currently valid sessions by
querying the session managing server 4. The user of each

client device 2 can select the session that the user
plans to participate in from the list without starting
the game program 22. At this point, the session managing
server 4 may reference the validity flag and thereby
offer only the information about the valid session to the
client device 2. As described above, the information
about the sessions for which the public flag is set to
off and to which the querying user is not invited is
excluded from the list of sessions offered to the client
device 2. The information about the sessions to which the
querying user is invited and the information about the
sessions to which the querying user is not invited are
acquired by querying the invitation managing server 5, to
be discussed later.
[ 0036]
By executing the game program 22, each client device 2
may let the game program 22 request a list of sessions
from the session managing server 4. In this case, the
client device 2 requests acquisition of the list
including the name of the game program 22 (i.e., game
title name) of the user who made the query. Given the
request, the session managing server 4 transmits to the
client device 2 only the information about the sessions
for which the querying user matches the game title name.
This allows the game program 22 to acquire only the

information about the sessions that can be participated
in. Alternatively, the client device 2 may request
acquisition of the list that includes the game ID
identifying the type of the game program 22 instead of
the game title name. In this case, the session managing
server 4 stores in relation to each session the game ID
identifying the game type corresponding to the session,
in place of or in addition to the game title name. Upon
receiving the list acquisition request, the session
managing server 4 transmits selectively to the client
device 2 the game ID included in the acquisition request
and the information about the session related to the
matching game ID.
[ 0037]
Explained below with reference to the flow diagram of FIG.
4 is an exemplary flow of processing performed by the
information processing system 1 in this embodiment when a
user participating in a session invites another user to
participate in the same session (i.e., the invitation is
extended from the inviting user to the invited user). In
the ensuing description, the client device 2 used by the
inviting user will be referred to as the client device 2a,
and the client device 2 used by the invited user will be
referred to as the client device 2b.
[ 0038]

The client device 2a executes the game program 22 to
connect with the service offering server 3 offering the
game service corresponding to the game program 22,
thereby participating in the session (step S11). At this
point, the client device 2a notifies the session managing
server 4 of the participation by the inviting user in the
session along with the session ID identifying the session
participated in (step S12). Given the notification, the
session managing server 4 adds the user ID of the
inviting user to the list of the participants in the
session identified by the session ID. Thereafter, under
instructions from the inviting user, the client device 2a
transmits to the invitation managing server 5 an
invitation request including the session ID transmitted
in step S12 as well as the user ID of the invited user
(step S13).
[0039]
On receiving the invitation request, the invitation
managing server 5 adds information about the invitation
to the database the invitation managing server 5 itself
manages (step S14), and requests the notification server
6 to send out an invitation notification (step S15). In
response to the request in step S15, the notification
server 6 notifies the client device 2b used by the
invited user of the invitation (step S16).

[0040]
Given the notification in step S16, the client device 2b
causes the display device 15 to indicate on its screen
that an invitation is extended (step S17). When the user
of the client device 2b gives an instruction to
participate in the session to which the user has been
invited, the client device 2b makes a session
participation request to the service offering server 3 as
when the inviting user participated in the session (step
S18). When the request to participate in the session is
received by the service offering server 3, the client
device 2b notifies the session managing server 4 to that
effect (step S19). This causes the user ID of the invited
user to be added to the list of the participants in the
session.
[ 0041]
Explained below is the information about the invitation
registered in the process of step S14 by the invitation
managing server 5 for management purposes. With regard to
each invitation accepted, the invitation managing server
5 stores as invitation-related information such related
items of information as an invitation ID, an inviting
user ID, an invited user ID, a session ID, an invitation
message, an invitation time, a session validity flag, a
read flag, and a participation flag.

[ 0042]
The invitation ID is information that uniquely identifies
each invitation and is given by the invitation managing
server 5. The inviting user ID and the invited user ID
are information identifying the inviting user and the
invited user, respectively. The session ID is information
that identifies the -session targeted by the invitation.
The invitation message is text' information indicating the
content of the message input by the inviting user and
addressed to the invited user. The invitation managing
server 5 is notified of the inviting user ID, invited
user ID, session ID, and invitation message by the client
device 2a used by the inviting user. The invitation time
is information indicative of the time at which the
invitation was extended. The date and time information in
effect when the invitation managing server 5 receives an
invitation request from the client device 2 is recorded
as the invitation time.
[ 0043]
The session validity flag is flag information indicating
whether the session targeted by the invitation is valid
or not. This information is similar to the validity flag
managed within the session managing server 4. It should
be noted that whereas the validity flag in the session
managing server 4 is updated in real time to the value

indicating that the session is invalid when ended, the
session validity flag in the invitation managing server 5
is not updated in real time. Upon transmitting invitation
information in response to the request from the client
device 2, the invitation managing server 5 references the
session validity flag regarding the invitation. If the
session validity flag is found set to invalid, the
invitation managing server 5 transmits to the client
device 2 the information about the invitation together
with information indicating that the session is already
invalid. If the session validity flag is found set to
valid, the invitation managing server 5 queries the
session managing server 4 about the most recent status of
the session before transmitting the information about the
invitation to the client device 2. The invitation
managing server 5 updates the session validity flag to
reflect the result of the query, before transmitting the
information about the invitation to the client device 2.
With this embodiment, the session will never be valid
again once made invalid. As mentioned above, the
invitation managing server 5 holds the session validity
flag independently of the session managing server 4. When
the session is already invalid, the invitation managing
server 5 can offer the client device 2 the information
about the invitation together with information indicating

that the session is invalid, without querying the session
managing server 4 a number of times. It is not mandatory
for the invitation managing server 5 to hold the session
validity flag. In this case, the invitation managing
server 5 may query the session managing server 4 about
the most recent status of the session every time the
invitation managing server 5 is about to offer invitation
information to the client device 2. The invitation
managing server 5 then offers the invitation information
together with the result of the query to the client "
device 2. As another alternative, the client device 2,
given the invitation information, may directly query the
session managing server 4 and acquire the flag
information indicative of the status of the session
targeted by the acquired invitation.
[ 0044]
The read flag is flag information indicating whether the
content of the invitation has been viewed by the invited
user or hot. The participation flag is another flag
information indicating whether the invited user has
participated in the session targeted by the invitation.
The client device 2b used by the invited user notifies
the invitation managing server 5 when the invited user
has viewed the content of the invitation or when the
invited user has participated in the session to which

that user has been invited. Given these notifications,
the invitation managing server 5 updates the read flag
and the participation flag accordingly.
[ 0045]
Explained below is the invitation-related information
displayed on the screen of the display device 15 by the
client device 2b of the invited user.
[ 0046]
When the user of the client device 2b gives an
instruction to display invitation information, the client
device 2b transmits to the invitation managing server 5 a
request to acquire the invitation information together
with the user ID of the user who has given the
instruction. The invitation information acquisition
. request may be made either by the system software 21 or
by the game program 22. In response to the acquisition
request, the invitation managing server 5 transmits to
the client device 2b the information about the
invitations in which the requesting user is the invited
user. At this point, as discussed above, the invitation
managing server 5 queries the session managing server 4
as needed to update the session validity flag to the most
recent information. The invitation managing server 5 then
transmits the invitation information together with the
information about the updated session validity flag. The

client device 2b displays the invitation information
received from the invitation managing server 5 in. list
form on the screen of the display device 5. When the game
program 22 makes the invitation information acquisition
request, only the information about the invitations
regarding the session corresponding to the game program
22 is offered to the client device 2.
[ 0047]
FIG. 5 is a schematic diagram showing an exemplary screen
displaying a list of invitation information. In FIG. 5,
each item of invitation information includes the game
title name of the session targeted by the invitation, a
session image, the name of the inviting user, and the
device type of the client device 2 that can participate
in the session. These items of invitation information are
acquired from the session managing server 4.
[ 0048]
In this embodiment, the client device 2b displays a list
of invitations in a manner reflecting the content of the
session validity flag. The client device 2b may also
display the information about invitations in a manner
reflecting the content of the read flag and the
participation flag. For example, the client device 2b may
display individual invitations in a manner determined by
each of the values of the session validity flag and the

read flag. In FIG. 5, a mark "New" is attached to each
invitation for which the read flag is set to "unread"
(i.e., the invitation has yet to be viewed by the invited
user) . The invitation for which the session validity flag
is set to "invalid" (i.e., the session targeted by the
invitation has already ended) may be displayed in a
manner not attracting much attention of the user, such as
a low-tone image obtained by suitable image processing.
In FIG. 5, the invitations enclosed by not a solid-line
rectangle but a broken-line rectangle each are shown as
the invitations of which the sessions have already ended.
As another alternative, the client device 2b may display
each invitation in a manner reflecting the participation
flag.
[ 0049]
The client device 2b may further determine the order in
which a plurality of invitations are to be displayed in
list form in accordance with the content of the session
validity flag, read flag, and participation flag. In FIG.
5, for example, the invitations targeted for display are
sorted by the value of the session validity flag. This
permits display of the invitations to the sessions that
are still valid and can be participated in by the user,
more preferentially than (i.e., higher than) the
invitations to the sessions that have already ended and

cannot be participated in. The invitations are also
sorted by the value of the read flag. When their session
validity flags are set to thesame value, the unread
invitations are displayed higher than the read
invitations. The invitations may further be sorted by the
content of the participation flag. For example, when
their session validity flags and their read flags are set
to the same values, the invitations yet to be
participated in may be displayed higher than the
invitations already participated in. However, because
viewing of an invitation needs to precede the
participation in that invited session, there usually is
no invitation that is unread and has been participated in.
Thus in determining the order in which to display
invitations in accordance with all of the session
validity flag, read flag, and participation flag, the
invitations may be displayed in list form in the
following order for example:
1. Invitations of which the sessions are valid, which
have yet to be read, and of which the sessions have yet
to be participated in.
2. Invitations of which the sessions are valid, which
have been read, and of which the sessions have yet to be
participated in.
3. Invitations of which the sessions are valid, which

have been read, and of which the sessions have been
participated in.
4. Invitations of which the sessions are invalid, which
have yet to be read, and of which the sessions have yet
to be participated in.
5. Invitations of which the sessions are invalid, which
have been read, and of which the sessions have yet to be
participated in.
6. Invitations of which the sessions are invalid, which
have been read, and of which the sessions have been
participated in.
In this manner, the invitations of which the sessions are
valid are displayed higher and more prominently than the
invitations of which the sessions are invalid. This
display helps direct the user' s attention to the
invitations that can still be participated in.
[0050]
The client device 2b may be arranged not to display, in
the invitation list on the screen, the invitations for
which the above-mentioned flags meet specific conditions.
For example, there is little need for the user who has
viewed the content of the invitations of which the
sessions have become invalid to again verify the content.
The invitations of which the sessions are invalid and
which have already been read may thus be excluded from

the invitation list targeted for display. If the user is
not expected to again participate in the session already
participated in, all invitations for which the
participation flags are set to "participated in" may be
excluded from the invitations targeted for display.
[ 0051]
In this embodiment, one user may use a plurality of
client devices 2. In such a case, it is the invitation
managing server 5 that holds the read flags and the
participation flags, not the client devices 2 in the
information processing system 1. This enables the
information processing system 1 to manage which user has
viewed which invitations and which user has participated
in which sessions on invitation, regardless of which of
the client devices 2 has been used.
[ 0052]
When the user selects one of the invitations listed on
the screen as shown in FIG. 5, a detailed display screen
appears, displaying the details of the selected
invitation. FIG. 6 is a schematic diagram showing an
exemplary detailed display screen of such invitation
information. On this detailed display screen, the
information about the content of the invitation (i.e.,
the user name of the inviting user and the invitation
message input by the inviting user) is displayed in the

top right corner of the screen. Shown on the left and in
the right bottom corner of the screen is detailed
information about the session targeted by the invitation
(e.g., game title name, session image, elapsed time since
the start of the session, accessory information, number
of participants in the session, and user name). The
detailed information about the session is acquired from
the session managing server 4. The elapsed time since the
start of the session, it should be noted, is calculated
from the current time information and from the session
generation time information acquired from the session
managing server 4. The client device 2b may request
acquisition of the detailed information about the session
directly from the session managing server 4.
Alternatively, when the client device 2b is to acquire
the invitation information from the invitation managing
server 5, the invitation managing server 5 may acquire
the detailed information about the session from the
session managing server 4 and offer the acquired
information along with the information managed by the
invitation managing server 5 to the client device 2b. The
timing for the client device 2b to acquire the detailed
information about the session is not limited to when the
invitation information is acquired from the invitation
managing server 5 to display a list of invitations.

Alternatively, the timing may be when the detailed
information about each invitation is displayed. In this
case, the most recent session status can be displayed on
the detailed display screen as the session images and
accessory information held by the session managing server
4 are updated over time.
[ 0053]
The detailed display screen for the invitation also
includes a "PARTICIPATE" button to be operated for
participating in the session. When the invited user
selectively operates the PARTICIPATE button, the client
device 2b starts the game program 22 corresponding to the
session to make a session participation request to the
service offering server 3. If the invited user having
operated the PARTICIPATE button to participate in the
session does not have the game program 22 corresponding
to the session, the client device 2b may access an online
program selling site and display the purchase screen of
the game program 22 to prompt the user to purchase the
game program 22.
[ 0054]
In the above-described embodiment of the present
invention, each invitation is related to the information
identifying the session targeted by the invitation. On
displaying the information about an invitation, the

client device 2b acquires in real time the status
information (validity flag) indicating whether the
related session is valid or not, and displays the
information about the session in a manner reflecting the
content. This allows the invited user, before accessing
the service offering server 3 and attempting to
participate in the session, to know whether the session
can be participated in or not.
[ 0055]
In this embodiment, in particular, the validity flag
indicating the status of each session is stored in the
session managing server 4 separate from the service
offering server 3. When the service offering server 3
generates a session anew, the information about the new
session is registered in the session managing server 4.
When the service offering server 3 ends the session, the
session managing server 4 is notified to that effect. The
notification causes the session managing server 4 to
update the validity flag stored therein regarding the
session, to the value indicative of invalidity. By
referencing the validity flag stored in the session
managing server 4, the client device 2b can thus acquire
the most recent status of the session without accessing
the service offering server 3. In this embodiment, the
client device 2 needs to start the corresponding game

program 22 in order to access the service offering server
3. However, because the session managing server 4 apart
from the service offering server 3 manages in real time
the status of each session generated by the service
offering server 3, the client device 2 can know whether
the session to which the client device 2 has been invited
can be participated in or not without starting the game
program 22.
[0056]
The embodiment of the present invention is not limited to
the one discussed above. For example, whereas it was
explained above that the service offering server 3 offers
the multiplayer game service, this is not limitative of
what the service offering server 3 has to offer. For
example, the service offering server 3 may generate
sessions for offering a chat, a voice chat, or other
diverse services in which a plurality of users may
concurrently participate online. In such cases, upon
participating in a session that offers a chat service for
example, the client device 2 may be required to execute
the application program corresponding to that service.
[ 0057]
It was also explained above that the inviting user while
participating in a session transmits an invitation for
the invited user to participate in the same session. In

another example, the sender of the invitation is not
limited to any of the users; a service provider may also
send out invitations. In this example, the service
offering server 3 may transmit invitation messages urging
the users who meet predetermined conditions or randomly
selected users to participate in the sessions managed by
the service offering server 3. In this case, upon having
a list of invitations displayed, the invited user
references the validity flags stored in the session
managing server 4. This enables the client device 2 of
the invited user to display in list form the sessions to
which the invitations have been extended, in a manner
distinguishing the currently valid sessions from the
ended sessions among the sessions to which the
invitations have been extended.
[ 0058]
The services offered by the information processing system
1 in this embodiment of the present invention are not
limited to those services in which the participation by a
plurality of users is mandatory. Specifically, the
present invention may be applied to any online service
which is not predetermined to stop being offered at any
specific point in time at the start of the service and
which can be accessed and used by the user while the
session offering the service is being valid. For example,

the present invention may be applied to a campaign
service or a time sale service at an electronic commerce
(EC) site. In this case, an inviting user or the service
provider notifies invited users of an invitation message
announcing the campaign service or the time sale service
being offered. When the invitation message is displayed,
the client device 2 of the invited user queries the
session managing server 4 to acquire flag information
indicating whether the service targeted by the invitation
is valid or not, before displaying the invitation message
in a manner reflecting the flag information.
[ 0059]
It was explained above that the service offering server 3,
the session managing server 4, the invitation managing
server 5, the notification server 6, and the client
managing server 7, all independent of one another, offer
the services of the information processing system 1.
However, the configuration of the server system for
offering the services of the information processing
system 1 is not limited to the above-described
configuration. For example, the function of the session
managing server 4 and that of the invitation managing
server 5 may be integrally implemented by a single server
computer. It was also explained above that the client
device 2 acquires necessary information by individually

accessing the session managing server 4 and the
invitation managing server 5. Alternatively, a reception
server may be provided to receive an information
acquisition request and an information update request
from the client device 2. The client device 2 may then
perform data communication with the reception server. In
this case, the client device 2 is connected to the
session managing server 4 and the invitation managing
server 5 indirectly via the reception server. In this
example, a request made by the client device 2 to acquire
invitation information from the reception server causes
the reception server to acquire from the invitation
managing server 5 the information about the invitations
in which the user using the client device 2 is the
invited user. The reception server also acquires from the
session managing server 4 the information about the
sessions targeted by the acquired invitations. The
reception server then transmits to the client device 2 a
replay that combines the invitation information acquired
from the invitation managing server 5 with the session
information acquired from the session managing server 4.
This enables the client device 2 to acquire the necessary
information without directly connecting with a plurality
of servers, alleviating the processing burdens on the
client side.

[ Reference Signs List]
[ 0060]
1: Information processing system, 2: Client device, 3:
Service offering server, 4: Session managing server, 5:
Invitation managing server, 6: Notification server, 7:
Client managing server, 11: Control section, 12: Storage
section, 13: Communication section, 14: Operation device,
15: Display device, 21: System software, 22: Game program.

[ CLAIMS]
[ Claim 1]
An information processing system including a plurality of
client devices and managing information about a plurality
of sessions each offering a service possibly participated
in by a user, the information processing system
comprising:
a session managing section configured to store status
information indicating whether each of the plurality of
sessions is valid or not; and
an invitation managing section configured to store a
plurality of items of invitation information, each of the
items of invitation information being about an invitation
for an invited user to participate in one of the
plurality of sessions,
wherein each of the plurality of client devices includes
an invitation information acquiring section configured to
acquire one of the plurality of items of invitation
information stored in the invitation managing section,
the acquired item of invitation information being about
the invitation for the user using the client device to
become the invited user; and
an invitation display controlling section configured to
display on a display screen the item of invitation
information acquired by the invitation information

acquiring section in a manner reflecting the status
information.
[Claim 2]
The information processing system according to claim 1,
wherein the invitation display controlling section
displays each of the plurality of items of invitation
information acquired by the invitation information
acquiring section in a manner indicative of whether the
session targeted by the item of invitation information is
valid or not.
[ Claim 3]
The information processing system according to claim 1,
wherein the invitation display controlling section
displays a list of the plurality of items of invitation
information acquired by the invitation information
acquiring section in an order determined by the status
information.
[ Claim 4]
The information processing system according to claim 1,
further comprising:
a service offering section configured to generate each of
the plurality of sessions and offer the service to the
user participating in any one of the generated sessions,
wherein, at the time the service offering section
generates a new session, the session managing section

stores the status information indicating that the newly
generated session is valid, the session managing section
further updating the status information to a value
indicating that the session is invalid at the time the
service offering section ends the session.
[ Claim 5]
The information processing system according to claim 4,
comprising:
a plurality of the service offering sections configured
to offer the services of which the types differ from one
another,
wherein the session managing section stores information
about the session generated by each of the plurality of
service offering sections.
[ Claim 6]
The information processing system according to claim 5,
wherein the client device executes a plurality of
application programs each corresponding to one of the
plurality of service offering sections; and
given a request from an executing one of the plurality of
application programs, the invitation information
acquiring section selectively acquires the invitation
information about the invitation to the session generated
by the service offering section corresponding to the
executing application program.

[ Claim 7]
A server system connected to a plurality of client
devices and managing information about a plurality of
sessions each offering a service possibly participated in
by a user, the server system comprising:
a session managing section configured to store status
information indicating whether each of the plurality of
sessions is valid or not;
an invitation managing section configured to store a
plurality of items of invitation information, each of the
items of invitation information being about an invitation
for an invited user to participate in one of the
plurality of sessions;
an invitation information offering section configured to
offer, when requested by one of the plurality of client
devices, one of the plurality of items of invitation
information stored in the. invitation managing section,
the offered item of invitation information being about
the invitation for the user using the requesting client
device to become the invited user; and
a status information offering section configured to offer
to the requesting client device the status information
stored in the session managing section regarding the
session targeted for invitation by the offered item of
invitation information,

wherein the offered status information is used when the
client device displays the offered item of invitation
information on a display screen.
[ Claim 8]
A client device connected to
a session managing section configured to store status
information indicating whether each of a plurality of
sessions offering a service possibly participated in by a
user is valid or not; and
an invitation managing section configured to store a
plurality of items of invitation information, each of the
items of invitation information being about an invitation
for an invited user to participate in one of the
plurality of sessions;
the client device comprising:
an invitation information acquiring section configured to
acquire one of the plurality of items of invitation
information stored in the invitation managing section,
the acquired item of invitation information being about
the invitation for the user using the client device to
become the invited user; and
an invitation display controlling section configured to
display on a display screen the item of invitation
information acquired by the invitation information
acquiring section in a manner reflecting the status

information.
[ Claim 9]
The client device according to claim 8, wherein the
invitation display controlling section displays on the
display screen the item of invitation information
acquired by the invitation information acquiring section
in a manner reflecting the status information while an
application program to be executed upon participation in
the session is not being executed.
[ Claim 10]
The client device according to claim 8, wherein, upon
participation in one of the plurality of sessions, the
client device is connected to a service offering section
and is offered a service therefrom, the serving offering
section offering the service to the user participating in
the session; and
the invitation display controlling section displays on
the display screen the item of invitation information
acquired by the invitation information acquiring section
in a manner reflecting the status information while the
client device is not being connected to the service
offering section.
[ Claim 11]
The client device according to claim 8, wherein the
invitation display controlling section displays on the

display screen the item of invitation information
acquired by the invitation information acquiring section,
together with information indicative of an elapsed time
since the start of the session targeted for invitation by
the acquired item of invitation information.
[ Claim 12]
A control method for a client device connected to
a session managing section configured to store status
information indicating whether each of a plurality of
sessions offering a service possibly participated in by a
user is valid or not; and
an invitation managing section configured to store a
plurality of items of invitation information, each of the
items of invitation information being about an invitation
for an invited user to participate in one of the
plurality of sessions;
the control method comprising:
a step of acquiring one of the plurality of items of
invitation information stored in the invitation managing
section, the acquired item of invitation information
being about the invitation for the user using the client
device to become the invited user; and
a step of displaying on a display screen the acquired
item of invitation information in a manner reflecting the
status information.

[ Claim 13]
A program for controlling a client device connected to
a session managing section configured to store status
information indicating whether each of a plurality of
sessions offering a service possibly participated in by a
user is valid or not; and
an invitation managing section configured to store a
plurality of items of invitation information, each of the
items of invitation information being about an invitation
for an invited user to participate in one of the
plurality of sessions;
the program causing the client terminal to execute:
a step of acquiring one of the plurality of items of
invitation information stored in the invitation managing
section, the acquired item of invitation information
being about the invitation for the user using the client
device to become the invited user; and
a step of displaying on a display screen the acquired
item of invitation information in a manner reflecting the
status information.
[ Claim 14]
A computer-readable information storage medium storing
the program according to claim 13.