Patent Publication Number: US-2011072372-A1

Title: Electronic device and method of controlling the same for determination of free time periods

Description:
TECHNICAL FIELD 
     The present invention relates generally to calendar applications and to determination of free time slots in an agenda. 
     BACKGROUND 
     Portable electronic devices including, for example, smart telephones and wireless PDAs are becoming increasingly common and typically integrate functions of personal information management such as calendaring and data communications such as email, World Wide Web browsing and telecommunications in a single device. Such devices run on a wide variety of networks from data-only networks such as Mobitex and DataTAC to complex voice and data networks such as GSMIGPRS, CDMA, EDGE, UMTS AND W-CDMA networks. 
     Calendar applications permit the user of the portable electronic device to schedule and review calendared events such as appointments and meetings on a visual display such as a liquid crystal display (LCD) screen. Calendared events can typically be viewed in any of a variety of layouts including, for example, a day view, a week view, a month view or an agenda view. An agenda view is typically a list of calendared events with date information, time information, and other identifying information such as subject information in the form of a table, to allow the user to quickly identify the calendared event in the list. Such an agenda is advantageous in that the user is provided with a convenient list of calendared events. To gain a better appreciation of the user&#39;s time schedule, the user is forced to switch to a day view, for example, to more quickly determine time available. Improvements in electronic device and for scheduling calendar events are desirable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein: 
         FIG. 1  is an example of a block diagram of an embodiment of a portable electronic device; 
         FIG. 2  is an example of a block diagram of a communication subsystem component of  FIG. 1 ; 
         FIG. 3  is an example of a block diagram of an implementation of a node of a wireless network; 
         FIG. 4  is an example of a block diagram illustrating components of an configuration of a host system with which the portable electronic device can communicate; 
         FIG. 5  is a flowchart showing the steps in a method for controlling an electronic device according to an embodiment of the present invention; 
         FIG. 6  is a flowchart showing the further steps of a block of  FIG. 5 ; 
         FIG. 7  is an example of a screen showing a list of calendared events display on the display of the portable electronic device; 
         FIG. 8  is another example of a screen showing a list of calendared events displayed on the portable electronic device; and 
         FIG. 9  is an example of a menu screen showing user options for the calendar application. 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. Also, the description is not to be considered to be limited to the scope of the embodiments described herein. 
     The embodiments described herein generally relate to portable electronic devices. Examples of portable electronic devices include mobile or handheld wireless communication devices such as pagers, cellular phones, cellular smart-phones, wireless organizers, personal digital assistants, computers, laptops, handheld wireless communication devices, wirelessly enabled notebook computers and the like. 
     The portable electronic device may be a two-way communication device with advanced data communication capabilities including the capability to communicate with other portable electronic devices or computer systems through a network of transceiver stations. The portable electronic device may also have the capability to allow voice communication. Depending on the functionality provided by the portable electronic device, it may be referred to as a data messaging device, a two-way pager, a cellular telephone with data messaging capabilities, a wireless Internet appliance, or a data communication device (with or without telephony capabilities). To aid the reader in understanding the structure of the portable electronic device and how it communicates with other devices and host systems, reference will now be made to  FIG. 1  through  FIG. 4 . 
     Referring first to  FIG. 1 , shown therein is an example of a block diagram of an embodiment of a portable electronic device  100 . The portable electronic device  100  includes a number of components such as a main processor  102  that controls the overall operation of the portable electronic device  100 . Communication functions, including data and voice communications, are performed through a communication subsystem  104 . Data received by the portable electronic device  100  can be decompressed and decrypted by a decoder  103 , operating according to any suitable decompression techniques (e.g. YK decompression, and other known techniques) and encryption techniques (e.g. using an encryption technique such as Data Encryption Standard (DES), Triple DES, or Advanced Encryption Standard (AES)). The communication subsystem  104  receives messages from and sends messages to a wireless network  200 . In this example embodiment of the portable electronic device  100 , the communication subsystem  104  is configured in accordance with the Global System for Mobile Communication (GSM) and General Packet Radio Services (GPRS) standards. The GSM/GPRS wireless network is used worldwide and it is expected that these standards will be superseded eventually by Enhanced Data GSM Environment (EDGE) and Universal Mobile Telecommunications Service (UMTS). New standards are still being defined, but it is believed that they will have similarities to the network behavior described herein, and it will also be understood by persons skilled in the art that the embodiments described herein are intended to use any other suitable standards that are developed in the future. The wireless link connecting the communication subsystem  104  with the wireless network  200  represents one or more different Radio Frequency (RF) channels, operating according to defined protocols specified for GSM/GPRS communications. With newer network protocols, these channels are capable of supporting both circuit switched voice communications and packet switched data communications. 
     Although the wireless network  200  associated with portable electronic device  100  is a GSM/GPRS wireless network in one implementation, other wireless networks may also be associated with the portable electronic device  100  in variant implementations. The different types of wireless networks that may be employed include, for example, data-centric wireless networks, voice-centric wireless networks, and dual-mode networks that can support both voice and data communications over the same physical base stations. Combined dual-mode networks include, but are not limited to, Code Division Multiple Access (CDMA) or CDMA2000 networks, GSM/GPRS networks (as mentioned above), and third-generation (3G) networks such as EDGE and UMTS. Some other examples of data-centric networks include WiFi 802.11, Mobitex™ and DataTAC™ network communication systems. Examples of other voice-centric data networks include Personal Communication Systems (PCS) networks like GSM and Time Division Multiple Access (TDMA) systems. The main processor  102  also interacts with additional subsystems such as a Random Access Memory (RAM)  106 , a memory  108 , a display  110 , an auxiliary input/output (I/O) subsystem  112 , a data port  114 , a trackball  115 , a keyboard  116 , a speaker  118 , a microphone  120 , short-range communications  122  and other device subsystems  124 . 
     Some of the subsystems of the portable electronic device  100  perform communication-related functions, whereas other subsystems may provide “resident” or on-device functions. By way of example, the display  110 , the trackball  115  and the keyboard  116  may be used for both communication-related functions, such as entering a text message for transmission over the network  200 , and device-resident functions such as a calculator or task list. 
     The portable electronic device  100  can send and receive communication signals over the wireless network  200  after network registration or activation procedures have been completed. Network access is associated with a subscriber or user of the portable electronic device  100 . To identify a subscriber, a SIM/RUIM card  126  (i.e. Subscriber Identity Module or a Removable User Identity Module) is inserted into a SIM/RUIM interface  128  in order to communicate with a network. The SIM/RUIM card  126  is a type of a conventional “smart card” that can be used to identify a subscriber of the portable electronic device  100  and to personalize the portable electronic device  100 , among other things. In the present embodiment, the portable electronic device  100  is not fully operational for communication with the wireless network  200  without the SIM/RUIM card  126 . By inserting the SIM/RUIM card  126  into the SIM/RUIM interface  128 , a subscriber can access all subscribed services. Services may include: web browsing and messaging such as e-mail, voice mail, Short Message Service (SMS), and Multimedia Messaging Services (MMS). More advanced services may include: point of sale, field service and sales force automation. The SIM/RUIM card  126  includes a processor and memory for storing information. Once the SIM/RUIM card  126  is inserted into the SIM/RUIM interface  128 , it is coupled to the main processor  102 . In order to identify the subscriber, the SIM/RUIM card  126  can include some user parameters such as an International Mobile Subscriber Identity (IMSI). An advantage of using the SIM/RUIM card  126  is that a subscriber is not necessarily bound by any single physical portable electronic device. The SIM/RUIM card  126  may store additional subscriber information for a portable electronic device as well, including datebook (or calendar) information and recent call information. Alternatively, user identification information can also be programmed into the memory  108 . 
     The portable electronic device  100  is a battery-powered device and includes a battery interface  132  for receiving one or more rechargeable batteries  130 . In at least some embodiments, the battery  130  can be a smart battery with an embedded microprocessor. The battery interface  132  is coupled to a regulator (not shown), which assists the battery  130  in providing power V+ to the portable electronic device  100 . Although current technology makes use of a battery, future technologies such as micro fuel cells may provide the power to the portable electronic device  100 . 
     The portable electronic device  100  also includes an operating system  134  and software components  136  to  146  which are described in more detail below. The operating system  134  and the software components  136  to  146  that are executed by the main processor  102  are typically stored in a persistent store such as the memory  108 , which may alternatively be a read-only memory (ROM) or similar storage element (not shown). Those skilled in the art will appreciate that portions of the operating system  134  and the software components  136  to  146 , such as specific device applications, or parts thereof, may be temporarily loaded into a volatile store such as the RAM  106 . Other software components can also be included, as is well known to those skilled in the art. 
     The subset of software applications  136  that control basic device operations, including data and voice communication applications are installed on the portable electronic device  100  during its manufacture. Other software applications include a message application  138  that can be any suitable software program that allows a user of the portable electronic device  100  to send and receive electronic messages. Various alternatives exist for the message application  138  as is well known to those skilled in the art. Messages that have been sent or received by the user are typically stored in the flash memory  108  of the portable electronic device  100  or some other suitable storage element in the portable electronic device  100 . In at least some embodiments, some of the sent and received messages may be stored remotely from the device  100  such as in a data store of an associated host system that the portable electronic device  100  communicates with. 
     The software applications can further include a device state module  140 , a Personal Information Manager (PIM)  142 , and other suitable modules (not shown). The device state module  140  provides persistence, i.e. the device state module  140  ensures that important device data is stored in persistent memory, such as the flash memory  108 , so that the data is not lost when the portable electronic device  100  is turned off or loses power. 
     The PIM  142  includes functionality for organizing and managing data items of interest to the user, such as, but not limited to, e-mail, contacts, calendar events, voice mails, appointments, and task items. PIM applications include, for example, calendar, address book, tasks and memo applications. The PIM applications have the ability to send and receive data items via the wireless network  200 . PIM data items may be seamlessly integrated, synchronized, and updated via the wireless network  200  with the portable electronic device subscriber&#39;s corresponding data items stored and/or associated with a host computer system. This functionality creates a mirrored host computer on the portable electronic device  100  with respect to such items. This can be particularly advantageous when the host computer system is the portable electronic device subscriber&#39;s office computer system. 
     The portable electronic device  100  also includes a connect module  144 , and an information technology (IT) policy module  146 . The connect module  144  implements the communication protocols that are required for the portable electronic device  100  to communicate with the wireless infrastructure and any host system, such as an enterprise system, that the portable electronic device  100  is authorized to interface with. Examples of a wireless infrastructure and an enterprise system are given in  FIG. 3  and  FIG. 4 , which are described in more detail below. 
     The connect module  144  includes a set of APIs that can be integrated with the portable electronic device  100  to allow the portable electronic device  100  to use any number of services associated with the enterprise system. The connect module  144  allows the portable electronic device  100  to establish an end-to-end secure, authenticated communication pipe with the host system. A subset of applications for which access is provided by the connect module  144  can be used to pass IT policy commands from the host system to the portable electronic device  100 . This can be done in a wireless or wired manner. These instructions can then be passed to the IT policy module  146  to modify the configuration of the device  100 . Alternatively, in some cases, the IT policy update can also be done over a wired connection. 
     Other types of software applications can also be provided on the portable electronic device  100  and still others can be installed on the portable electronic device  100 . Such software applications can be third party applications, which are added after the manufacture of the portable electronic device  100 . Examples of third party applications include games, calculators, utilities, etc. 
     The additional applications can be loaded onto the portable electronic device  100  through at least one of the wireless network  200 , the auxiliary I/O subsystem  112 , the data port  114 , the short-range communications subsystem  122 , or any other suitable device subsystem  124 . This flexibility in application installation increases the functionality of the portable electronic device  100  and may provide enhanced on-device functions, communication-related functions, or both. For example, secure communication applications may enable electronic commerce functions and other such financial transactions to be performed using the portable electronic device  100 . 
     The data port  114  enables a subscriber to set preferences through an external device or software application and extends the capabilities of the portable electronic device  100  by providing for information or software downloads to the portable electronic device  100  other than through a wireless communication network. The alternate download path may, for example, be used to load an encryption key onto the portable electronic device  100  through a direct and thus reliable and trusted connection to provide secure device communication. 
     The data port  114  can be any suitable port that enables data communication between the portable electronic device  100  and another computing device. The data port  114  can be a serial or a parallel port. In some instances, the data port  114  can be a USB port that includes data lines for data transfer and a supply line that can provide a charging current to charge the battery  130  of the portable electronic device  100 . 
     The short-range communications subsystem  122  provides for communication between the portable electronic device  100  and different systems or devices, without the use of the wireless network  200 . For example, the subsystem  122  may include an infrared device and associated circuits and components for short-range communication. Examples of short-range communication standards include standards developed by the Infrared Data Association (IrDA), Bluetooth, and the 802.11 family of standards developed by IEEE. 
     In use, a received signal such as a text message, an e-mail message, Web page download, or any other information is processed by the communication subsystem  104  and input to the main processor  102 . The main processor  102  will process the received signal for output to the display  110  or alternatively to the auxiliary I/O subsystem  112 . A subscriber may also compose data items, such as e-mail messages, for example, using the keyboard  116  in conjunction with the display  110  and possibly the auxiliary I/O subsystem  112 . The auxiliary subsystem  112  may include devices such as: a touch screen, mouse, track ball, infrared fingerprint detector, or a roller wheel with dynamic button pressing capability. The keyboard  116  can be an alphanumeric keyboard and/or telephone-type keypad. However, other types of keyboards may also be used. A composed item may be transmitted over the wireless network  200  through the communication subsystem  104 . 
     For voice communications, the overall operation of the portable electronic device  100  is substantially similar, except that the received signals are output to the speaker  118 , and signals for transmission are generated by the microphone  120 . Alternative voice or audio I/O subsystems, such as a voice message recording subsystem, can also be implemented on the portable electronic device  100 . Although voice or audio signal output is accomplished primarily through the speaker  118 , the display  110  can also be used to provide additional information such as the identity of a calling party, duration of a voice call, or other voice call related information. 
     Referring now to  FIG. 2 , an example of a block diagram of the communication subsystem component  104  is shown. The communication subsystem  104  includes a receiver  150 , a transmitter  152 , as well as associated components such as one or more embedded or internal antenna elements  154  and  156 , Local Oscillators (LOs)  158 , and a processing module such as a Digital Signal Processor (DSP)  160 . The particular design of the communication subsystem  104  is dependent upon the communication network  200  with which the portable electronic device  100  is intended to operate. Thus, it should be understood that the design illustrated in  FIG. 2  serves only as one example. 
     Signals received by the antenna  154  through the wireless network  200  are input to the receiver  150 , which may perform such common receiver functions as signal amplification, frequency down conversion, filtering, channel selection, and analog-to-digital (A/D) conversion. A/D conversion of a received signal allows more complex communication functions such as demodulation and decoding to be performed in the DSP  160 . In a similar manner, signals to be transmitted are processed, including modulation and encoding, by the DSP  160 . These DSP-processed signals are input to the transmitter  152  for digital-to-analog (D/A) conversion, frequency up conversion, filtering, amplification and transmission over the wireless network  200  via the antenna  156 . The DSP  160  not only processes communication signals, but also provides for receiver and transmitter control. For example, the gains applied to communication signals in the receiver  150  and the transmitter  152  may be adaptively controlled through automatic gain control algorithms implemented in the DSP  160 . 
     The wireless link between the portable electronic device  100  and the wireless network  200  can contain one or more different channels, typically different RF channels, and associated protocols used between the portable electronic device  100  and the wireless network  200 . An RF channel is a limited resource that should be conserved, typically due to limits in overall bandwidth and limited battery power of the portable electronic device  100 . 
     When the portable electronic device  100  is fully operational, the transmitter  152  is typically keyed or turned on only when it is transmitting to the wireless network  200  and is otherwise turned off to conserve resources. Similarly, the receiver  150  is periodically turned off to conserve power until it is needed to receive signals or information (if at all) during designated time periods. 
     Referring now to  FIG. 3 , an example of a block diagram of an implementation of a node  202  of the wireless network  200  is shown. In practice, the wireless network  200  comprises one or more nodes  202 . In conjunction with the connect module  144 , the portable electronic device  100  can communicate with the node  202  within the wireless network  200 . In the implementation of  FIG. 3 , the node  202  is configured in accordance with General Packet Radio Service (GPRS) and Global Systems for Mobile (GSM) technologies. The node  202  includes a base station controller (BSC)  204  with an associated tower station  206 , a Packet Control Unit (PCU)  208  added for GPRS support in GSM, a Mobile Switching Center (MSC)  210 , a Home Location Register (HLR)  212 , a Visitor Location Registry (VLR)  214 , a Serving GPRS Support Node (SGSN)  216 , a Gateway GPRS Support Node (GGSN)  218 , and a Dynamic Host Configuration Protocol (DHCP)  220 . This list of components is not meant to be an exhaustive list of the components of every node  202  within a GSM/GPRS network, but rather a list of components that are commonly used in communications through the network  200 . 
     In a GSM network, the MSC  210  is coupled to the BSC  204  and to a landline network, such as a Public Switched Telephone Network (PSTN)  222  to satisfy circuit switched requirements. The connection through the PCU  208 , the SGSN  216  and the GGSN  218  to a public or private network (Internet)  224  (also referred to herein generally as a shared network infrastructure) represents the data path for GPRS capable portable electronic devices. In a GSM network extended with GPRS capabilities, the BSC  204  also contains the Packet Control Unit (PCU)  208  that connects to the SGSN  216  to control segmentation, radio channel allocation and to satisfy packet switched requirements. To track the location of the portable electronic device  100  and availability for both circuit switched and packet switched management, the HLR  212  is shared between the MSC  210  and the SGSN  216 . Access to the VLR  214  is controlled by the MSC  210 . 
     The station  206  is a fixed transceiver station and together with the BSC  204  form fixed transceiver equipment. The fixed transceiver equipment provides wireless network coverage for a particular coverage area commonly referred to as a “cell”. The fixed transceiver equipment transmits communication signals to and receives communication signals from portable electronic devices within its cell via the station  206 . The fixed transceiver equipment normally performs such functions as modulation and possibly encoding and/or encryption of signals to be transmitted to the portable electronic device  100  in accordance with particular, usually predetermined, communication protocols and parameters, under control of its controller. The fixed transceiver equipment similarly demodulates and possibly decodes and decrypts, if necessary, any communication signals received from the portable electronic device  100  within its cell. Communication protocols and parameters may vary between different nodes. For example, one node may employ a different modulation scheme and operate at different frequencies than other nodes. 
     For all portable electronic devices  100  registered with a specific network, permanent configuration data such as a user profile is stored in the HLR  212 . The HLR  212  also contains location information for each registered portable electronic device and can be queried to determine the current location of a portable electronic device. The MSC  210  is responsible for a group of location areas and stores the data of the portable electronic devices currently in its area of responsibility in the VLR  214 . Further, the VLR  214  also contains information on portable electronic devices that are visiting other networks. The information in the VLR  214  includes part of the permanent portable electronic device data transmitted from the HLR  212  to the VLR  214  for faster access. By moving additional information from a remote HLR  212  node to the VLR  214 , the amount of traffic between these nodes can be reduced so that voice and data services can be provided with faster response times and at the same time requiring less use of computing resources. 
     The SGSN  216  and the GGSN  218  are elements added for GPRS support; namely packet switched data support, within GSM. The SGSN  216  and the MSC  210  have similar responsibilities within the wireless network  200  by keeping track of the location of each portable electronic device  100 . The SGSN  216  also performs security functions and access control for data traffic on the wireless network  200 . The GGSN  218  provides internetworking connections with external packet switched networks and connects to one or more SGSN&#39;s  216  via an Internet Protocol (IP) backbone network operated within the network  200 . During normal operations, a given portable electronic device  100  must perform a “GPRS Attach” to acquire an IP address and to access data services. This requirement is not present in circuit switched voice channels as Integrated Services Digital Network (ISDN) addresses are used for routing incoming and outgoing calls. Currently, all GPRS capable networks use private, dynamically assigned IP addresses, thus requiring the DHCP server  220  connected to the GGSN  218 . There are many mechanisms for dynamic IP assignment, including using a combination of a Remote Authentication Dial-In User Service (RADIUS) server and a DHCP server. Once the GPRS Attach is complete, a logical connection is established from a portable electronic device  100 , through the PCU  208 , and the SGSN  216  to an Access Point Node (APN) within the GGSN  218 . The APN represents a logical end of an IP tunnel that can either access direct Internet compatible services or private network connections. The APN also represents a security mechanism for the network  200 , insofar as each portable electronic device  100  must be assigned to one or more APNs and portable electronic devices  100  cannot exchange data without first performing a GPRS Attach to an APN that it has been authorized to use. The APN may be considered to be similar to an Internet domain name such as “myconnection.wireless.com”. 
     Once the GPRS Attach operation is complete, a tunnel is created and all traffic is exchanged within standard IP packets using any protocol that can be supported in IP packets. This includes tunneling methods such as IP over IP as in the case with some IPSecurity (IPsec) connections used with Virtual Private Networks (VPN). These tunnels are also referred to as Packet Data Protocol (PDP) Contexts and there are a limited number of these available in the network  200 . To maximize use of the PDP Contexts, the network  200  will run an idle timer for each PDP Context to determine if there is a lack of activity. When a portable electronic device  100  is not using its PDP Context, the PDP Context can be de-allocated and the IP address returned to the IP address pool managed by the DHCP server  220 . 
     Referring now to  FIG. 4 , shown therein is an example of a block diagram illustrating components of an configuration of a host system  250  that the portable electronic device  100  can communicate with in conjunction with the connect module  144 . The host system  250  will typically be a corporate enterprise or other local area network (LAN), but may also be a home office computer or some other private system, for example, in variant implementations. In this example shown in  FIG. 4 , the host system  250  is depicted as a LAN of an organization to which a user of the portable electronic device  100  belongs. Typically, a plurality of portable electronic devices can communicate wirelessly with the host system  250  through one or more nodes  202  of the wireless network  200 . 
     The host system  250  comprises a number of network components connected to each other by a network  260 . For instance, a user&#39;s desktop computer  262   a  with an accompanying cradle  264  for the user&#39;s portable electronic device  100  is situated on a LAN connection. The cradle  264  for the portable electronic device  100  can be coupled to the computer  262   a  by a serial or a Universal Serial Bus (USB) connection, for example. Other user computers  262   b - 262   n  are also situated on the network  260 , and each may or may not be equipped with an accompanying cradle  264 . The cradle  264  facilitates the loading of information (e.g. PIM data, private symmetric encryption keys to facilitate secure communications) from the user computer  262   a  to the portable electronic device  100 , and may be particularly useful for bulk information updates often performed in initializing the portable electronic device  100  for use. The information downloaded to the portable electronic device  100  may include certificates used in the exchange of messages. 
     It will be understood by persons skilled in the art that the user computers  262   a - 262   n  will typically also be connected to other peripheral devices, such as printers, etc. which are not explicitly shown in  FIG. 4 . Furthermore, only a subset of network components of the host system  250  are shown in  FIG. 4  for ease of exposition, and it will be understood by persons skilled in the art that the host system  250  will comprise additional components that are not explicitly shown in  FIG. 4  for this configuration. More generally, the host system  250  may represent a smaller part of a larger network (not shown) of the organization, and may comprise different components and/or be arranged in different topologies than that shown in the embodiment of  FIG. 4 . 
     To facilitate the operation of the portable electronic device  100  and the wireless communication of messages and message-related data between the portable electronic device  100  and components of the host system  250 , a number of wireless communication support components  270  can be provided. In some implementations, the wireless communication support components  270  can include a management server  272 , a mobile data server (MDS)  274 , a web server, such as Hypertext Transfer Protocol (HTTP) server  275 , a contact server  276 , and a device manager module  278 . HTTP servers can also be located outside the enterprise system, as indicated by the HTTP server  275  attached to the network  224 . The device manager module  278  includes an IT Policy editor  280  and an IT user property editor  282 , as well as other software components for allowing an IT administrator to configure the portable electronic devices  100 . In an alternative embodiment, there may be one editor that provides the functionality of both the IT policy editor  280  and the IT user property editor  282 . The support components  270  also include a data store  284 , and an IT policy server  286 . The IT policy server  286  includes a processor  288 , a network interface  290  and a memory unit  292 . The processor  288  controls the operation of the IT policy server  286  and executes functions related to the standardized IT policy as described below. The network interface  290  allows the IT policy server  286  to communicate with the various components of the host system  250  and the portable electronic devices  100 . The memory unit  292  can store functions used in implementing the IT policy as well as related data. Those skilled in the art know how to implement these various components. Other components may also be included as is well known to those skilled in the art. Further, in some implementations, the data store  284  can be part of any one of the servers. 
     In this embodiment, the portable electronic device  100  communicates with the host system  250  through node  202  of the wireless network  200  and a shared network infrastructure  224  such as a service provider network or the public Internet. Access to the host system  250  may be provided through one or more routers (not shown), and computing devices of the host system  250  may operate from behind a firewall or proxy server  266 . The proxy server  266  provides a secure node and a wireless internet gateway for the host system  250 . The proxy server  266  intelligently routes data to the correct destination server within the host system  250 . 
     In some implementations, the host system  250  can include a wireless VPN router (not shown) to facilitate data exchange between the host system  250  and the portable electronic device  100 . The wireless VPN router allows a VPN connection to be established directly through a specific wireless network to the portable electronic device  100 . The wireless VPN router can be used with the Internet Protocol (IP) Version 6 (IPV6) and IP-based wireless networks. This protocol can provide enough IP addresses so that each portable electronic device has a dedicated IP address, making it possible to push information to a portable electronic device at any time. An advantage of using a wireless VPN router is that it can be an off-the-shelf VPN component, and does not require a separate wireless gateway and separate wireless infrastructure. A VPN connection can be a Transmission Control Protocol (TCP)/IP or User Datagram Protocol (UDP)/IP connection for delivering the messages directly to the portable electronic device  100  in this alternative implementation. 
     Messages intended for a user of the portable electronic device  100  are initially received by a message server  268  of the host system  250 . Such messages may originate from any number of sources. For instance, a message may have been sent by a sender from the computer  262   b  within the host system  250 , from a different portable electronic device (not shown) connected to the wireless network  200  or a different wireless network, or from a different computing device, or other device capable of sending messages, via the shared network infrastructure  224 , possibly through an application service provider (ASP) or Internet service provider (ISP), for example. 
     The message server  268  typically acts as the primary interface for the exchange of messages, particularly e-mail messages, within the organization and over the shared network infrastructure  224 . Each user in the organization that has been set up to send and receive messages is typically associated with a user account managed by the message server  268 . Some examples of implementations of the message server  268  include a Microsoft Exchange™ server, a Lotus Domino™ server, a Novell Groupwise™ server, or another suitable mail server installed in a corporate environment. In some implementations, the host system  250  may comprise multiple message servers  268 . The message server provides additional functions including PIM functions such as calendaring, contacts and tasks and supports data storage. 
     When messages are received by the message server  268 , they are typically stored in a data store associated with the message server  268 . In at least some embodiments, the data store may be a separate hardware unit, such as data store  284 , that the message server  268  communicates with. Messages can be subsequently retrieved and delivered to users by accessing the message server  268 . For instance, an e-mail client application operating on a user&#39;s computer  262   a  may request the e-mail messages associated with that user&#39;s account stored on the data store associated with the message server  268 . These messages are then retrieved from the data store and stored locally on the computer  262   a . The data store associated with the message server  268  can store copies of each message that is locally stored on the portable electronic device  100 . Alternatively, the data store associated with the message server  268  can store all of the messages for the user of the portable electronic device  100  and only a smaller number of messages can be stored on the portable electronic device  100  to conserve memory. For instance, the most recent messages (i.e. those received in the past two to three months for example) can be stored on the portable electronic device  100 . 
     When operating the portable electronic device  100 , the user may wish to have e-mail messages retrieved for delivery to the portable electronic device  100 . The message application  138  operating on the portable electronic device  100  may also request messages associated with the user&#39;s account from the message server  268 . The message application  138  may be configured (either by the user or by an administrator, possibly in accordance with an organization&#39;s IT policy) to make this request at the direction of the user, at some pre-defined time interval, or upon the occurrence of some pre-defined event. In some implementations, the portable electronic device  100  is assigned its own e-mail address, and messages addressed specifically to the portable electronic device  100  are automatically redirected to the portable electronic device  100  as they are received by the message server  268 . 
     The management server  272  can be used to specifically provide support for the management of, for example, messages, such as e-mail messages, that are to be handled by portable electronic devices. Generally, while messages are still stored on the message server  268 , the management server  272  can be used to control when, if, and how messages are sent to the portable electronic device  100 . The management server  272  also facilitates the handling of messages composed on the portable electronic device  100 , which are sent to the message server  268  for subsequent delivery. 
     For example, the management server  272  may monitor the user&#39;s “mailbox” (e.g. the message store associated with the user&#39;s account on the message server  268 ) for new e-mail messages, and apply user-definable filters to new messages to determine if and how the messages are relayed to the user&#39;s portable electronic device  100 . The management server  272  may also, through an encoder  273 , compress messages, using any suitable compression technology (e.g. YK compression, and other known techniques) and encrypt messages (e.g. using an encryption technique such as Data Encryption Standard (DES), Triple DES, or Advanced Encryption Standard (AES)), and push them to the portable electronic device  100  via the shared network infrastructure  224  and the wireless network  200 . The management server  272  may also receive messages composed on the portable electronic device  100  (e.g. encrypted using Triple DES), decrypt and decompress the composed messages, re-format the composed messages if desired so that they will appear to have originated from the user&#39;s computer  262   a , and re-route the composed messages to the message server  268  for delivery. 
     Certain properties or restrictions associated with messages that are to be sent from and/or received by the portable electronic device  100  can be defined (e.g. by an administrator in accordance with IT policy) and enforced by the management server  272 . These may include whether the portable electronic device  100  may receive encrypted messages or signed messages or both encrypted and signed messages, minimum encryption key sizes, whether outgoing messages must be encrypted or signed or encrypted and signed, and whether copies of all secure messages sent from the portable electronic device  100  are to be sent to a pre-defined copy address, for example. 
     The management server  272  may also be adapted to provide other control functions, such as only pushing certain message information or pre-defined portions (e.g. “blocks”) of a message stored on the message server  268  to the portable electronic device  100 . For example, in some cases, when a message is initially retrieved by the portable electronic device  100  from the message server  268 , the management server  272  may push only the first part of a message to the portable electronic device  100 , with the part being of a pre-defined size (e.g. 2 KB). The user can then request that more of the message be delivered in similar-sized blocks by the management server  272  to the portable electronic device  100 , possibly up to a maximum pre-defined message size. Accordingly, the management server  272  facilitates better control over the type of data and the amount of data that is communicated to the portable electronic device  100 , and can help to minimize potential waste of bandwidth or other resources. 
     The MDS  274  encompasses any other server that stores information that is relevant to the corporation. The mobile data server  274  may include, but is not limited to, databases, online data document repositories, customer relationship management (CRM) systems, or enterprise resource planning (ERP) applications. The MDS  274  can also connect to the Internet or other public network, through HTTP server  275  or other suitable web server such as an File Transfer Protocol (FTP) server, to retrieve HTTP webpages and other data. Requests for webpages are typically routed through MDS  274  and then to HTTP server  275 , through suitable firewalls and other protective mechanisms. The web server then retrieves the webpage over the Internet, and returns it to MDS  274 . As described above in relation to management server  272 , MDS  274  is typically provided, or associated, with an encoder  277  that permits retrieved data, such as retrieved webpages, to be compressed, using any suitable compression technology (e.g. YK compression, and other known techniques), and encrypted (e.g. using an encryption technique such as DES, Triple DES, or AES), and then pushed to the portable electronic device  100  via the shared network infrastructure  224  and the wireless network  200 . 
     The contact server  276  can provide information for a list of contacts for the user in a similar fashion as the address book on the portable electronic device  100 . Accordingly, for a given contact, the contact server  276  can include the name, phone number, work address and e-mail address of the contact, among other information. The contact server  276  can also provide a global address list that contains the contact information for all of the contacts associated with the host system  250 . 
     It will be understood by persons skilled in the art that the management server  272 , the MDS  274 , the HTTP server  275 , the contact server  276 , the device manager module  278 , the data store  284  and the IT policy server  286  do not need to be implemented on separate physical servers within the host system  250 . For example, some or all of the functions associated with the management server  272  may be integrated with the message server  268 , or some other server in the host system  250 . Alternatively, the host system  250  may comprise multiple management servers  272 , particularly in variant implementations where a large number of portable electronic devices need to be supported. 
     The device manager module  278  provides an IT administrator with a graphical user interface with which the IT administrator interacts to configure various settings for the portable electronic devices  100 . As mentioned, the IT administrator can use IT policy rules to define behaviors of certain applications on the portable electronic device  100  that are permitted such as phone, web browser or Instant Messenger use. The IT policy rules can also be used to set specific values for configuration settings that an organization requires on the portable electronic devices  100  such as auto signature text, WLAN/VoIP/VPN configuration, security requirements (e.g. encryption algorithms, password rules, etc.), specifying themes or applications that are allowed to run on the portable electronic device  100 , and the like. 
     As indicated above, the portable electronic device  100  includes the Personal Information Manager (PIM)  142  that includes functionality for organizing and managing data items of interest to the user, such as, but not limited to, e-mail, contacts, calendar events, voice mails, appointments, and task items. PIM applications include, for example, calendar, address book, tasks and memo applications. 
     It will be appreciated that a calendar application is used for providing a graphical user interface (GUI) for the user to create calendared events and for storage of the calendared events in a database, when executed by the microprocessor  102 . The calendar application is also used for displaying calendared events such as appointments, lectures, exams, movies, meetings, performances, dinners, ceremonies, etc. as described below. Each calendared event includes a variety of information including a date and time of the event. The terms date/time, working day and calendar day are used throughout the present description. It will be appreciated that the term date/time refers to time and date, working day refers to time period within a calendar day during which a user is available for calendared events, and calendar day refers to a date. 
     The display  110  of the portable electronic device  100  can be configured by a user to display visual representations of the calendared events that are stored in a database. The calendared events are displayed in a user-selected one of various calendar views including a day view, a week view, a month view and an agenda view. The agenda view provides a list of calendared events with date information, time information, and other identifying information such as subject information in the form of a table, to allow the user to quickly identify calendared events in the list. 
     Selection of the calendar application by the user causes execution of the calendar application by the microprocessor  102  and a user-selected one or default one of the calendar views is displayed on the display  110 . In the agenda calendar view, a list of calendared events is displayed beginning at the current date according to an internal clock of the portable electronic device  100 . The calendared events scheduled for different calendar days are listed under different day headings, with all calendar events for a specific day listed under the same calendar day heading. The user can scroll ahead in time in the agenda view to show further future calendared events using, for example, the trackball  115 . Similarly, the user can scroll back in time in the agenda view to show past calendared events using, for example, the trackball  115 . 
     Each calendared event in the list includes information such as the start time of the calendared event, the end time of the calendared event, the subject information relating to the calendared event, and location information relating to the calendared event. It will be appreciated that the list of calendared events is not limited to this information and other information can be presented. For example, rather than displaying the end time of the calendared event, the duration of the event may be displayed. It is also possible that some information such as location information is not included. Further, an indication of whether or not a reminder is set for the calendared event and an indication that the calendared event is a recurring event can be displayed. 
     The following generally describes an apparatus and a method of controlling an electronic device, the method comprising retrieving, from at least one database comprising a plurality of calendared events, calendared events for a calendar day, and for the calendar day, determining free time periods between an earliest of a start time of a working day and an end time of a first calendared event and a latest of the end time of the working day and a start time of a last calendared event; and rendering the calendared events and the determined free time periods in a time-ordered list on a display of the electronic device. 
     Reference is now made to  FIG. 5  to describe an embodiment of a method of the present application. It will be appreciated that each of the steps of  FIG. 5  is carried out by routines or subroutines of the calendar software executed by the microprocessor  102 . Coding of software for carrying out such a method is within the scope of a person of ordinary skill in the art given the present description. Upon selection of the calendar application from a menu screen (not shown) by a user of the portable electronic device  100 , the microprocessor  102  executes a routine of the calendar application. For the purpose of the present example, the calendar application default view is the agenda view. It will be appreciated, however, that the default view can be any view, and the view can be changed from any other view to the agenda view by user selection of an agenda view option in a calendar options menu referred to below. 
     As indicated above, a list of calendared events is rendered in the agenda view. To display this list, all calendared events for a current calendar day are retrieved  300  from one or more databases in which the calendared events are stored. After retrieving  300  the calendared events for a calendar day, a single time-ordered list of calendared events for the current calendar day is created  302 , thereby placing each of the calendared events in order of start time of the calendared events. 
     Next, the earliest of a start time of a working day of the current calendar day and an end time of a first calendar event of the current calendar day is determined  304 . After determining  304  the earliest of the start time of the working day and the end time of the first calendar event, the latest of the end of the working day of the current calendar day and the start of a last calendar event of the current calendar day is determined  306 . Next, free time periods for the current calendar day are determined  308  between the earliest of a start time of the working day and the end time of the first calendared event and the latest of the end time of the working day and the start time of a last calendared event. When all the free time periods for the current calendar day have been determined  308 , a determination is made whether calendar events for a next calendar day are to be retrieved  310 . Such determination can be based on user preference of how many calendar days to show (see  612  of  FIG. 9 ) or other criterion (e.g., screen area available). When it is determined that calendar events for a next calendar day are to be retrieved  310 , each of determining  304  of the earliest of the start time of the working day and an end time of a first calendar event, determining  306  of the latest of the end of the working day and the start of a last calendar event, and determining free time periods is repeated for the next calendar day. It will be appreciated that the number of calendar days for which free time periods will be determined may be configured to a default number (for example three, one, etc.) and may be changed by a user of the portable electronic device. When the free time periods for the configured number of calendar days have been determined  310 , the calendar events and the determined free time periods for each calendar day are rendered  312  in a time-ordered list on the display  110  of the portable electronic device  100 , thereby providing the user with free time slots available to schedule further calendar events. 
     The determination  308  of free time periods for a calendar day will now be described with reference to  FIG. 6 . To determine  314  the start of the first free time period for the current calendar day a search is conducted for the earliest of the start time of the working day for the current calendar day and the end time for the first calendar event for the current calendar day according to the internal clock of the portable electronic device  100 . Thus, when no calendared event is scheduled before the start time of the working day (i.e., calendar events with an end time before the start time of the working day of the current calendar day) or that is in progress at the start time of the working day, the start time of the first free time period is determined to be the start of the working day of the current calendar day. When there are calendared events scheduled before the start time of the working of the current calendar day or a calendared event is in progress at the start time of the working day of the current calendar day, the start time of the first free time period is determined to be the end time of the first calendar event of the current calendar day. 
     After determining  314  the start time of the first free time period, the end time for the first free time period is determined  316 . In this case, the first one of the start time of a non-conflicting calendared event, the latest of the end time of the working day and the start time of the last calendar event, and the earliest start time of a set of conflicting calendar events is determined. Thus, if there are no further calendar events for the current calendar day, the end time of the free time period is determine to be the end time of the working day of the current calendar day. On the other hand, if there are other calendared events for the current calendar day, the next earliest one of either a start time of a non-conflicting calendared event, the earliest start time of a set of conflicting calendared events or the latest of the end time of the working day and the start time of the last calendar event of the current calendar day is determined to be the end time of the first free time period. 
     The duration of the free time period is then determined  318  by subtracting the start time of the free time period from the end time of the free time period. The determined duration is then compared  320  to a minimum duration. For any free time periods that have a duration less than the minimum duration or that have an end time that is on or before the current time according to the internal clock of the portable electronic device  100 , these time periods are not added to the time ordered-list. Instead, the process proceeds to step  324 . However, for free time periods that have a duration greater than or equal to the minimum duration of time, the free time period is added  322  to the time-ordered list. Very short free time periods are therefore not displayed. Thus, the time-ordered list that is rendered in an agenda view is not cluttered with very short free time periods that, for example, are too short for scheduling further calendared events within or with past free time periods. It will be appreciated that the minimum duration can be set to zero so that all free time periods are rendered in the time-ordered list regardless of their durations. Also, the minimum duration can be user-selectable in a calendar graphical user interface menu. Showing free time periods between back-to-back calendar events can be prohibited, even when the minimum duration of a free time period is set to zero. 
     After a determination is made  322  whether or not to add the first free time period to the time-order list, a determination is made  324  whether further free time periods for the current calendar day are to be determined. When a determination is made  324  that further free time periods are to be determined for the current calendar day, steps  314 ,  316 ,  318 ,  320  and  322  are each repeated for the next time period. 
     When all free time periods of the current calendar day and other calendar days for which calendar events are to be retrieved are determined and all free time periods having a duration greater than or equal to the minimum duration are added to the time-ordered list, the time-ordered list is rendered  312  on the display  110  of the portable electronic device  100 , thereby providing the user with a visual indication of the free time slots that are available for scheduling of further calendar events. 
     It will be appreciated that in the present embodiment, free time periods are only shown beginning at the current date/time according to the internal clock. Free time periods are not shown for past date/times. 
     Referring now to  FIG. 7 , an example of an agenda view showing a list of calendared events  404 ,  408 ,  410 ,  412  for three calendar days  402 ,  416 ,  420  according one embodiment is shown. The start times and end times of each of the calendared events  404 ,  408 ,  410 ,  412  for each of the calendar days  402 ,  416 ,  420  are rendered. Also, the start times and end times of each of the free time periods  406 ,  414 ,  418 ,  422  are rendered. In this example, the free time periods  406 ,  414 ,  418 ,  422  are rendered with a different display attribute to facilitate easy identification. For example, each of the free time periods  406 ,  414 ,  418 ,  422  is rendered in a normal weight font rather than a bold font. Other display attributes can be used for display. For example, the free time periods  406 ,  414 ,  418 ,  422  can be shown in a different font (e.g., “Times New Roman” vs “Anal”) or in bold, in italics, in an alternative colour or can be rendered with any other suitable differentiating display attribute. It will be appreciated that in the example of  FIG. 7  only four calendared events are shown and four free time periods are shown, although more or fewer may exist. A header  400  is shown, indicating the current date and time. 
     Continued reference is now made to  FIG. 5  and  FIG. 7 . In the example of  FIG. 7 , four calendared events  404 ,  408 ,  410 ,  412  are retrieved  300  from the database and a single time ordered list is created  302  ( FIG. 5 ). It will be appreciated that the working day is configured to a start time of 9:00 AM and an end time of 5:00 PM for the present example. Next, the earliest of the start time of working day of the current calendar day  402  and the end time of the first calendar event  404  of the current calendar day  402  is then determined  304 . In this example, the start of the working day is 9:00 AM and the first calendar event  404  of the current calendar day  402  is scheduled to end at 8:00 AM, therefore the start of the first free time period  406  is determined to be 8:00 AM. In effect the free time period  406  has been extended in length (from the normal start of the work day at 9:00 AM to the earlier 8:00 AM), as it is assumed that the user is available after the calendared event “Marketing Meeting” scheduled from 7:00 AM to 8:00 AM. This avoids having time periods appear to be missing from the agenda view, which would be the case if the free time period  406  were not extended. (The period from 8:00 AM to 9:00 AM would be unaccounted for.) One result is therefore an agenda view filled entirely with contiguous calendared events and/or free time periods (aside from any shorter than minimum intervals that are not designated as free time periods). It will be appreciated that any past free time periods are not determined. 
     Next, the latest of the end time of the working day of the current calendar day  402  and the start time of last calendar event  412  of the current calendar day  402  is determined  306 . In this example, the end time of the working day is 5:00 PM and the last calendared event  412  of the current calendar day  402  ends at 4:00 PM, free time periods  406 ,  414  between 8:00 AM and 5:00 PM are then determined  308  for the current calendar day  402 . 
     Continued reference is now made to  FIG. 6  and  FIG. 7 . To determine  308  the free time periods  406 ,  414  for the current calendar day  402 , the start time of the first free time period is determined  314 . In this example, the start time of the first free time period  406  is determined to be 8:00 AM. Next, the end time of the first free time period  406  is determined  316 . In this example, as the next calendared event  408  is scheduled to begin at 11:00 AM, the end time of the first free time period  406  is determined  316  to be 11:00 AM, which is the start time of the next calendared event  408  of the current calendar day  402 . After the end time of the first free time period  406  is determined, the duration of the first free time period  406  is determined  318 . For the purposes of this example, the minimum duration is set at 15 minutes. In this example, the duration of the first free time period  406  is determined  320  to be 3 hours. Next, the duration of the first free time period is compared to the minimum duration at  320 . In this example, because the first free time period  406  is greater in duration than the minimum duration, the first free time period is added  322  to the time order list. Next, the start time of the next free time period for the current calendar day  402  is determined. The second calendar event  410  is scheduled to end at 12:00 PM and the third calendar event is scheduled to start at 12:00 PM. Thus, the duration of the next free time period is determined  318  to be zero, which is less than the minimum duration, as determined at  320 , and this is not added as a free time period to the time-ordered list. Next, the start time of the next free time period for the current calendar day  402  is determined. In this example, the third calendar event  410  is scheduled to end at 2:00 PM and the fourth calendar event is scheduled to start at 2:00 PM. Thus, the duration of the next free time period is determined  318  to be zero, which is less than the minimum duration, as determined at  320 . This is not added as a free time period in the time-ordered list. Next, the start time of the next free time period for the current calendar day  402  is determined. In this example, the start time of the next free time period  414  is determined  316  to be 4:00 PM, which is the end time of the fourth calendared event  412 . The duration of this next free time period  414  is then determined  320 . As mentioned above, as the end time of the working day has been configured to 5:00 PM in this example and the last calendared event  412  of the current calendar day  402  ends at 4:00 PM, the end time of the next free time period is determined to be 5:00 PM. After the end time of the next free time period  414  is determined, the duration of the next free time period  414  is determined  318 . In this example, the duration of the next free time period  414  is determined  318  to be 1 hour. This duration is then compared  318  to the minimum duration and because the duration is greater than the minimum duration, the next free time period  414  is added  322  to the time-ordered list. In this example, because there are no further calendar events in the current calendar day  402  and the end time of the working day has passed, no further free time periods are determined. 
     Using the example that calendar application is configured to render two calendar days after the current calendar day  402 , free time periods are determined for each of the next two calendar days  416 ,  422 . In this example, only the current calendar day  402  includes calendared events  404 ,  408 ,  410 ,  412 . The free time period  418  for the calendar day  416  after the current calendar day  402  is determined to span the full working day (i.e. from the start time of the working day (9:00 AM in this example) to the end time of the working day (5:00 PM in this example)). Similarly, the free time period  422  for the day after the next calendar day  422  is also determined to span the full length of the entire working day (i.e. 9:00 AM-5:00 PM). Once the free time periods  406 ,  414 ,  418 ,  422  for the calendar days  402 ,  416 ,  420  are determined, the calendar events  404 ,  408 ,  410 ,  412  and the determined free time periods  406 ,  414 ,  418 ,  422  are rendered  312  on the display  110  of the portable electronic device  100 . 
     Referring now to  FIG. 8 , an example of an agenda view showing a list of calendared events  506 ,  508 ,  510 ,  514  for three calendar days  502 ,  516 ,  520  according another embodiment is shown. The start times and end times of each of the calendared events  506 ,  508 ,  510 ,  514  for each of the calendar days  502 ,  516 ,  520  are rendered. Also, the start times and end times of each of the free time periods  504 ,  512 ,  518 ,  522  are rendered. Again, in this case, the free time periods  504 ,  512 ,  518 ,  522  are rendered with a different display attribute to facilitate easy identification. It will be appreciated that in the embodiment of  FIG. 8  only four calendared events are shown and four free time periods are shown. A header  500  is shown, indicating the current date and time. 
     Continued reference is now made to  FIG. 5  and  FIG. 8 . For the purpose of the present example, four calendared events  506 ,  508 ,  510 ,  514  are retrieved  300  from the database and a time ordered list is created  302  ( FIG. 5 ). For the purposes of this example, the working day is configured to start at 9:00 AM and end at 5:00 PM. The earliest of the start time of working day for the current calendar day  502  and the end time of the first calendar event  504  of the current calendar day  502  is determined  304 . In this example, because the start of the working day is 9:00 AM and the first calendar event  504  of the current calendar day  502  is scheduled to end at 12:00 PM, the start time of the first free time period  504  is determined  314  to be 9:00 AM, which is the start time of the working day. It will be appreciated that any past free time periods are not determined. 
     Next, the latest of the end time of the working day of the current calendar day  502  and the start time of last calendar event  516  of the current calendar day  502  is determined  306 . In this example, as the end time of the working day is 5:00 PM and the last calendared event  514  of the current calendar day  502  ends at 7:00 PM, all free time periods  406 ,  414  between 9:00 AM and 7:00 PM are then determined  308  for the current calendar day  502 . In this example, the free time period  512  has been extended in length (from the normal end of the work day at 5:00 PM to the later 6:00 PM), as it is assumed that the user is available between 5:00 PM and the start of the calendared event “Sales Meeting” scheduled from 6:00 PM to 7:00 PM. This avoids having time periods appear to be missing from the agenda view, which would be the case if the free time period  512  were not extended. (The period from 5:00 PM to 6:00 PM would be unaccounted for.) One result is therefore an agenda view filled entirely with contiguous calendared events and/or free time periods (aside from any shorter than minimum intervals that are not designated as free time periods). 
     Continued reference is now made to  FIG. 6  and  FIG. 8 . To determine  308  the free time periods  504 ,  512  for the current calendar day  502 , the start time of the first free time period  504  is determined  314 . In this example, the start time of the first free time period  504  is determined  314  to be the start time of the working day, that is, 9:00 AM. Next, the end time of the first free time period  504  is determined  316 . As the next calendared event  506  is scheduled to begin at 11:00 AM, the end time of the first free time period  504  is determined  316  to be the start time of the next calendar event  506 , which is 11:00 AM. After the end time of the first time period  504  is determined  316 , the duration of the first free time period  504  is determined  318 . For the purposes of this example, the minimum duration is set at 15 minutes. In this example, the duration of the first free time period  504  is determined  320  to be 2 hours, which is greater than the minimum duration determined at  320 . Thus, the first free time period  504  is added  322  (to the time order list. As the end time of the working day of the current calendar day  502  is 5:00 PM and the last calendared event  514  of the current calendar day  502  ends at 7:00 PM, further free time periods for the calendar day  502  are determined  324 . Next, the start time of the next free time period  512  for the current calendar day  502  is determined. In this example, the second calendar event  410  is scheduled to end at 12:00 PM and the third calendar event is scheduled to start at 12:00 PM. Thus, the duration is determined  318  to be zero, which is less than the minimum duration, as determined at  320 , and this is not added as a free time period in the time-ordered list. Next, the start time of the next free time period for the current calendar day  402  is determined. In this example, the third calendar event  410  is scheduled to end at 2:00 PM and the fourth calendar event is scheduled to start at 2:00 PM. Thus, the duration is determined  318  to be zero, which is less than the minimum duration, as determined at  320 , and this is not added to the time-ordered list. Next, the start time of the next free time period for the current calendar day  402  is determined. In this example, the start time of the next free time period  512  is determined to be 4:00 PM. Next, the end time of the next free time period  512  is determined  316 . Because the last calendar event  514  of the current calendar day  502  ends after the end time of the working day of the current calendar day  502 , the end time of the next free time period  512  is determined to be the start time of the last calendar event  514  of the current calendar day  502 . After the end time of the next free time period  512  is determined, the duration of the next free time period  512  is determined  320  to be 2 hours, which is greater than the minimum duration determined at  320 . Thus, the next free time period  512  is added to the time order list. There are no further calendar events in the current calendar day  502  and the last calendar event  514  ends after the end of the working day, therefore no further free time periods are determined. 
     Using the example that calendar application has been configured to render two calendar days after the current calendar day  502 , free time periods are determined for the next calendar day  516  after the current calendar day  502  and the calendar day  520  after the next calendar day  516 . In this example, only the current calendar day  502  includes calendared events  506 ,  508 ,  510 ,  512 , the free time period  518  for the calendar day  516  after the current calendar day  502  is determined to span the full working day (i.e. from the start time of the working day (9:00 AM in this example) to the end time of the working day (5:00 PM in this example)). Similarly, the free time period  522  for the day after the next calendar day  520  is also determined to span the full length of the entire working day (i.e. 9:00 AM-5:00 PM). Once the free time periods  504 ,  512 ,  518 ,  522  for the calendar days  502 ,  516 ,  520  are determined, the calendar events  506 ,  508 ,  510 ,  514  and the determined free time periods  504 ,  512 ,  518 ,  522  are rendered  312  on the display  110  of the portable electronic device  100 . 
     Referring to  FIG. 9 , there is shown an example of a menu screen that has user options for the calendar application. The default view when a calendar application is selected may be selected by a user. For example, when a user selects the Initial View Option  600 , the user may be presented with a list (not shown) of Day View, Week View and Month View to choose from to set the default view to another calendar view. The Start of Working Day  602  and End of Working Day  604  in the calendar views are user-configurable by selecting the Start of Working Day  602  or End of Working Day  604  options and using, for example, the trackball  115  to change the time listed. It will be appreciate that changing the times of the Start of Working Day  602  or End of Working Day  604  may or may not affect the times determined and shown in  FIG. 7  and  FIG. 8 . Changing either of these options may cause the execution of the method of  FIG. 5  and  FIG. 6  again to thereby recalculate the free time periods for rendering on the display  110  of the portable electronic device  100 . The font attribute of the free time rendered on the display  100  is also configurable user selection of the Free Time Attribute  606  option. 
     Furthermore, the user may be also be provided with the option to turn off or on the free time in the agenda view depending on user preferences by toggling between Yes and No in the Show Free Time Agenda  608  option and can set the minimum duration of a free time period for display by selecting the “Min. Free Time Displayed” option  610  and increasing or decreasing the minimum duration (e.g., 15 minutes, 30 minutes, 5 minutes, etc.). The number of calendar days rendered in the agenda view may also be set by selecting the “Number of Entries” option  612  and increasing or decreasing the number by using, for example, the trackball  115 . 
     In another embodiment, free time periods are determined and added to the time-ordered list irrespective of the minimum duration (selected at option  610 ). Then, the durations of free time periods are compared to the minimum duration, and a free time period is not displayed in the agenda view when its duration is less than the minimum duration. Thus, shorter than minimum free time periods exist in the time-ordered list, but are simply not rendered on the agenda view of the time-ordered list. 
     According to one aspect, there is provided a method of controlling an electronic device, the method comprising: retrieving, from at least one database comprising a plurality of calendared events, calendared events for a calendar day; and for the calendar day determining free time periods between an earliest of a start time of a working day and an end time of a first calendared event and a latest of the end time of the working day and a start time of a last calendared event; and rendering the calendared events and the determined free time periods in a time-ordered list on a display of the electronic device. 
     According to another aspect, there is provided an electronic device comprising: a display device; a memory; a processor operably connected to the display device and the memory, the processor being configured to execute computer-readable code stored in the memory to cause the electronic device to retrieve, from at least one database comprising a plurality of calendared events, calendared events for a calendar day; determine free time periods, for the calendar day, between an earliest of a start time of a working day and an end time of a first calendared event and a latest of the end time of the working day and a start time of a last calendared event; and render, for the calendar day, the calendared events and the determined free time periods in a time-ordered list on a display of the electronic device. 
     According to another aspect, there is provided a computer program product for rendering calendared events on a display of an electronic device, the computer program product comprising a computer-readable medium having computer-readable code embodied therein executable by a processor of the electronic device to cause the electronic device to retrieve, from at least one database comprising a plurality of calendared events, calendared events for a calendar day; determine free time periods, for the calendar day, between an earliest of a start time of a working day and an end time of a first calendared event and a latest of the end time of the working day and a start time of a last calendared event; and render, for the calendar day, the calendared events and the determined free time periods in a time-ordered list on the display. 
     Advantageously, when a calendar event is scheduled before the start of the working day or after the end of the working day of a calendar day, the working day is extended and free time periods in which calendared events are not scheduled are determined for the extended working day for the calendar day. The calendared events for calendar days are provided to the user along with the free time periods in a time-ordered list. The user or other users can therefore schedule new appointments in free time periods that are available. A quick, “at a glance” view of the list provides information to the user, explicitly showing free time available so that the user can easily find an appropriate length of available free time for scheduling a further meeting or appointment. This obviates the need to switch between different views to schedule a further meeting or appointment, which reduces user interaction time with the device. Thus, the device use time is reduced in scheduling further meetings and appointments, reducing power consumption and battery use of the portable electronic device, thereby extending the battery life of the portable electronic device. In addition, in the case of a first user wishing to schedule a calendar event with a second user, precursory communications between the users to clarify free time durations can be reduced when the second user&#39;s free time is displayed to the first user as extended. For example, the first user does not have to call the second user to confirm that the second user is free outside the normal work day (e.g., from 5:00 PM to 6:00 PM, in  FIG. 8 ). Without such extension of free time, additional battery power would be wasted to place such clarifying calls. 
     In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments of the invention. However, it will be apparent to one skilled in the art that these specific details are not required in order to practice the invention. In other instances, well-known electrical structures and circuits are shown in block diagram form in order not to obscure the invention. For example, specific details are not provided as to whether the embodiments of the invention described herein are implemented as a software routine, hardware circuit, firmware, or a combination thereof. 
     Embodiments of the invention can be represented as a software product stored in a machine-readable medium (also referred to as a computer-readable medium, a processor-readable medium, or a computer usable medium having a computer-readable program code embodied therein). The machine-readable medium can be any suitable tangible medium, including magnetic, optical, or electrical storage medium including a diskette, compact disk read only memory (CD-ROM), memory device (volatile or non-volatile), or similar storage mechanism. The machine-readable medium can contain various sets of instructions, code sequences, configuration information, or other data, which, when executed, cause a processor to perform steps in a method according to an embodiment of the invention. Those of ordinary skill in the art will appreciate that other instructions and operations necessary to implement the described invention can also be stored on the machine-readable medium. Software running from the machine-readable medium can interface with circuitry to perform the described tasks. 
     The above-described embodiments of the invention are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.