22-01-2010, 07:13 AM
[attachment=1315]
ABSTRACT
Symbian OS is the operating system licensed by the world's leading mobile phone manufacturers. Symbian OS is designed for the specific requirements of open, data-enabled 2G, 2.5G and 3G mobile phone.Key features of symbian,how symbian supports modern features of mobile phones are discussed briefly.
1 INTRODUCTION
Symbian OS is the operating system licensed by the world's leading mobile phone manufacturers. Symbian OS is designed for the specific requirements of open, data-enabled 2G, 2.5G and 3G mobile phones. Symbian OS is already available in the Ericsson R380, Sony-Ericsson P800, the Nokia 9200 Communicator series, Nokia 7650 etc¦
Symbian OS is characterised by:
¢ Integrated multimode mobile telephony “ Symbian OS integrates the power of computing with mobile telephony, bringing advanced data services to the mass market
¢ Open application environment “ Symbian OS enables mobile phones to be a platform for deployment of applications and services (programs and content) developed in a wide range of languages and content formats
¢ Open standards and interoperability “ With a flexible and modular implementation, Symbian OS provides a core set of application programming interfaces (APIs) and technologies that is shared by all Symbian OS phones. Key industry standards are supported
¢ Multi-tasking “ Symbian OS is based on a micro kernel architecture and implements full multi-tasking and threading. System services such as telephony, networking middleware and application engines all run in their own processes
¢ Fully Object-oriented and component based “ The operating system has been designed from the ground up with mobile devices in mind, using advanced OO techniques, leading to a flexible component based architecture
¢ Flexible user interface design “ By enabling flexible graphical user interface design on Symbian OS, Symbian is fostering innovation and is able to offer choice to manufacturers, carriers, enterprises and end-users. Using the same core operating system in different designs also eases application porting for third party developers .
2. MOBILE PHONE CORE PLATFORM
Symbian OS is a 32-bit, little-endian operating system. It has been ported to many flavors of ARM architecture chips with V4 instruction set or higher. Further requirements of Symbian OS are for the CPU to have an integrated memory management unit (MMU) and a cache, to operate in various privileged access modes, and to handle interrupts and exceptions. The CPU, MMU and cache along with timers and hardware drivers, all reside on the system-on-chip. These SoCs are often commercially available and are sometimes custom built by handset manufactures.
Symbian OS has been ported to many ARM cored system-on-chips. These include the PrimeXSys platform from ARM, the StrongARM and XScale architectures from Intel, the OMAP platform from Texas Instruments and the Dragonball platform from Motorola.
Figure 1: Mobile phone hardware can be divided into three logical layers: the CPU core, the SoC and the PCB. Symbian OS also conforms to this layering. This enables easy porting of Symbian OS as the code for particular CPU core or SoC can be reused in many products.
The MMU is used for several purposes. It protects process data from access by other processes, enforces protection of application and kernel code, and isolates the hardware from application code. The MMU is a crucial component in the design of the protected mode system, which enhances both the security and stability of the platform. A standard two-level page tabled MMU allows small 4 KB pages for efficient memory usage, while fast re-mapping speeds can be achieved with large first-level pages of 1 MB. Both data and instruction caches are required to produce acceptable performance. On-chip timers provide the real-time clock for the system tick timer, and millisecond scale timers are needed for use with hardware drivers.
While some memory will be available on the chip most will be provided off-chip. This off-chip memory has three major functions: storage of the Symbian OS image; persistence of user data in a file system; and storage of processes' data at runtime. Speed of memory access, cost of the memory chips and persistence of the data must be considered when choosing the memory for each of these three functions.
3. HARDWARE ACCESS
The Symbian OS kernel is a compact pre-emptive multitasking operating system with very little dependence on peripherals. The core kernel executable - of less than 200 KB - fully supports the multi-threaded operating system. Peripheral hardware integration is added to the kernel in several ways. Hardware support is usually implemented in separate DLLs associated with particular hardware to allow the easy insertion and removal of hardware and to facilitate code reuse.
The MMU is configured so that all hardware registers can only be accessed in privileged mode. The kernel always executes in privileged mode and hence has access to all the hardware registers. Applications interface to kernel services through an API provided by the User library.
The kernel library includes support for all peripheral hardware that is resident on the chip (e.g., the ASIC or SoC) and that is essential to the operating system. The peripheral hardware includes such things as timers, DMA engines, interrupt controllers and UART serial ports. The kernel library is customized for a particular chip. Applications are not permitted to access peripheral hardware directly. Instead applications must page link to the User library whose functions may invoke peripheral control through the kernel.
Peripherals associated with user input can be packaged as a separate DLL, called a kernel extension. User input simply provides events that are consumed by the kernel. Different kernel extensions can be written for keyboard, keypad, digitizer, and navigation button
and wheels. The appropriate kernel extensions are added into the image, where the kernel detects their presence at boot time and initializes them. The kernel itself has no dependency on the extensions, and no kernel extension functionality is accessible to applications.
Figure 2: All access to hardware occurs from, or through the kernel. There are several software frameworks that support hardware access, direct kernel access for vital hardware, kernel extensions for hardware associated with user input, and device drivers for further peripheral hardware exposed to applications and server.
Device drivers expose an API to applications to allow control of hardware that is not essential to running the operating system. Device drivers can be loaded and unloaded at anytime. A device driver consists of two parts: a library providing the device's API to which applications can link; and one or two libraries, running in privileged mode, kernel-side, to access the hardware.
4. KEY FEATURES OF SYMBIAN OS
Symbian OS provides a rich core of application programming interfaces that are common to all Symbian OS phones. Key features of Symbian OS are:
¢ Rich suite of application engines “ the suite includes engines for contacts, schedule, messaging, browsing, utility and system control; OBEX for exchanging objects such as appointments (using the industry standard vCalendar) and business cards (vCard); integrated APIs for data management, text, clipboard and graphics
¢ Browsing “ a WAP stack is provided with support for WAP 1.2.1 for mobile browsing
¢ Messaging “ multimedia messaging (MMS), enhanced messaging (EMS) and SMS; internet mail using POP3, IMAP4, SMTP and MHTML; attachments; fax
¢ Multimedia “ audio and video support for recording, playback and streaming; image conversion
¢ Graphics “ direct access to screen and keyboard for high performance; graphics accelerator API
¢ Communications protocols “ wide-area networking stacks including TCP/IP (dual mode IPv4/v6) and WAP, personal area networking support include infrared (IrDA), Bluetooth and USB; support is also provided for multihoming capabilities and page link layer Quality-of-Service (QoS) on GPRS/UMTS networks
¢ Mobile telephony “ Symbian OS v7.0s is ready for the 3G market with support for GSM circuit switched voice and data (CSD and EDGE ECSD) and packet-based data (GPRS and EDGE EGPRS); CDMA circuit switched voice, data and packet-based data (IS-95, cdma2000 1x, and WCDMA); SIM, RUIM and UICC Toolkit; Other standards can be implemented by licensees through extensible APIs of the telephony subsystem
¢ International support “ conforms to the Unicode Standard version 3.0
¢ Data synchronization “ over-the-air (OTA) synchronization support using SyncML; PC-based synchronization over serial, Bluetooth, Infrared and USB; a PC Connectivity framework providing the ability to transfer files and synchronize PIM data
¢ Security “ full encryption and certificate management, secure protocols (HTTPS, WTLS and SSL and TLS), WIM framework and certificate-based application installation
¢ Developing for Symbian OS “ content development options include: C++, Java (J2ME) MIDP 2.0 and PersonalJava 1.1.1a (with JavaPhone 1.0 option), and WAP; tools are available for
building C++ and Java applications and ROMs with support for on-target debugging
¢ User Inputs “ generic input mechanism supporting full keyboard, 0-9*# (numeric mobile phone keypad), voice, handwriting recognition and predictive text input.
New in Symbian OS v7.0s
Symbian OS v7.0s provides new functionality providing a fit-for-purpose platform for the 3G market and enabling the OS for 3GPP compliance, enabling the delivery of 3G services.
The major new features of Symbian OS v7.0s are:
¢ lightweight multi-threaded multimedia framework
¢ support for W-CDMA
¢ Java MIDP 2.0, Bluetooth 1.1 and Wireless Messaging 1.0 profiles
¢ support for multiple primary/secondary PDP contexts
¢ support for bi-directional text (Thai, Arabic and Hebrew).
5. TELEPHONY
The Telephony subsystem provides a multimode API to its clients. The abstract cellular networks include GSM, GPRS, EDGE, CDMA (IS-95) and cdma2000 1x (Release A). The multimode telephony abstraction is key in Symbian OS to providing integration with the rest of the operating system to enable creation of advanced data services.
Functionality common to all networks includes:
¢ phone and network information: retrieve signal and battery strengths, provide access to the network names detected by the phone, information about the current network, receive notifications when there are network registration changes and retrieve the phone identity information
¢ phonebook: read, write, search and delete access to the phonebook storage areas of the phone and SIM (GSM 11.11) or R-UIM (cdma2000 1x)
¢ both one-box and two-box configurations are supported
¢ phonebook synchronizer: mechanism to synchronize phonebook entries stored on a SIM or R-UIM card to the contact database so that clients can access all contact data via the contacts model API.
5.1. GSM/EDGE telephony
Support for GSM, GPRS and EDGE conforms to the 3GPP GSM Phase 2+ (releases R97/98).
5.1.1 GSM
The GSM telephony framework provides an abstract telephony interface for GSM voice, data and fax, and for landline modems for data and fax as well as phone number resolution and SIM Application Toolkit. Main features are:
¢ voice calls: initiate, terminate and answer voice calls
¢ circuit-switched data calls: initiate, terminate and answer data calls including HSCSD. Pass the control of serial port to communication protocols to stream data
¢ the abstraction supports a wide variety of ETSI GSM phase 2+ functionality
¢ supplementary services supported include: Alternative Line Service (ALS), Alternating Call Services (between voice and data, and voice and fax), retrieve NITZ time information, call forwarding, call waiting, call barring, Called/Calling Party Identity Presentation (CLIP) and Restriction (CLIR), setting up Closed User Group (CUG) call, User-User signalling (UUS), conference call, charging information, message waiting identification, network service requests (USSD).
5.1.2 GPRS
The General Packet Radio Service (GPRS) framework provides an abstract telephony interface for GPRS class B functionality. With class B functionality, phones are able to make and receive GSM calls while simultaneously remaining registered with GPRS. If a Packet Data Protocol context is active, GPRS services are automatically suspended and resumed. The main features are:
¢ attachment and detachment from the GPRS network
¢ activation and deactivation of a Packet Data Protocol (PDP) context for data transfer
¢ ability to activate and deactivate the PDP context automatically with no explicit client intervention
¢ ability to automatically suspend a GPRS data connection when an incoming or outgoing GSM voice call is made, and to resume a suspended GPRS data connection on notification from the GPRS network
¢ information and notification service to the client software of network information such as GPRS capabilities, current GPRS network availability, change in the current state of a GPRS connection and general PDP contexts parameters.
5.1.3 EDGE
The Enhanced Data-rates for Global Evolution (EDGE) framework provides an abstract telephony interface for 3GPP GSM/EDGE. In addition to supporting the GSM and GPRS functionality described above, main features are:
¢ supports EDGE enhanced CSD (ECSD)
¢ supports EDGE enhanced GPRS (EGPRS).
5.2. CDMA telephony
5.2.1 CDMA
The CDMA telephony framework provides an abstract telephony interface for CDMA (IS-95) voice, data (circuit- and packet-switched) and fax. Main features are:
¢ voice calls: initiate, terminate and answer voice calls
¢ circuit-switched data: support for service options: asynchronous data and fax for both rate Set 1 and rate Set 2
¢ packet-switched data: support for service options: CDPD for both rate Set 1 and rate Set 2
¢ text messaging (SMS): SMS support is provided by an abstraction of the interface between the SMS teleservice layer and the SMS transport layer (IS-637)
¢ operation in AMPS (Voice only) networks
¢ forward compatibility with cdma2000 networks
5.2.2 cdma2000 1x
The 3GPP2 cdma2000 1x telephony framework provides an abstract telephony interface for 3GPP2 cdma2000 1x (Release A) voice, data (circuit- and packet-switched) and fax. In addition to the functionality of CDMA (IS-95) described above, main features are:
¢ circuit-switched data: support for IS-95B services
¢ packet-switched data: support for IS-95B services plus service options 22-29, 33, 34 for high speed packet data
¢ Removable-User Identity Module (R-UIM): support access to R-UIM files such as phonebook entries and stored SMS messages
¢ phonebook synchronizer: mechanism to synchronize phonebook entries stored on a SIM or R-UIM card to the contact database so that clients can access all contact data via the contacts model API.
6. COMMUNICATION INFRASTRUCTURE
The Comms Infrastructure subsystem provides the key frameworks and system services for communications and networking. This includes:
¢ a communications database manager which controls the system-wide communications configuration
¢ a socket server and client-side API which provides a framework for implementing various communications protocols through a socket interface. Plug-in protocols are dynamically loaded
¢ a network interface manager which provides a framework for connection to other computers or networks. The manager provides a mechanism for the client to monitor progress over e.g., a PPP connection
¢ a serial communications server provides a serial port (RS232C) abstraction to allow Symbian OS phones to function as a DCE and a DTE as required. Dynamically loadable plug-in communications modules are used to actually communicate with device drivers and other protocol stacks.
¢ HTTP and WAP stacks.
6.1 Networking
A dual stack is provided that supports both IPv4 and IPv6.
Networking support in Symbian OS includes:
¢ Transmission Control Protocol (TCP)
¢ User Datagram Protocol (UDP)
¢ IPv4/v6 stack. The TCP/IP stack provides a plug-in architecture. Plug-ins can interact with OSI level 2, 3 and 4 components and can be installed, loaded and unloaded at runtime. IP-based Symbian OS clients such as email, HTTP, SSL, Java MIDP, SyncML over HTTP and web can use IPv6 addressing as well as IPv4 addressing:
o Internet Control Message Protocol (ICMP)
o Point to Point Protocol (PPP)
o Domain Name System (DNS)
o dial up networking support
o security protocols for secure electronic commerce: Transport Layer Security (TLS) and Secure Sockets Layer (SSL)
o File Transfer Protocol (FTP) engine
o Ethernet support: wired interface (PCMCIA cards for WINS and on-board Ethernet chip for development board) supports 10BaseT and 100BaseTX in full or half duplex; Wireless interface (IrLAN); Support for Slow IR.
6.2. HTTP transport framework
Symbian provides a generalized framework for Internet applications to use HTTP like protocols. The framework presents a unified, high level API that is independent of particular header representations, specific protocol details or the underlying transport layer. This framework is used as the interface to HTTP and WSP protocols.
The framework allows for extension and customization at an application or platform level by the use of filter plug-ins.
6.2.1 HTTP client stack
HTTP 1.0 and 1.1 Client stack with support for persistent connections, pipelining, and chunked transfer encoding.
Enables applications such as SyncML, OCSP, Web Based Application Installation. This stack can also be used by Third Parties for applications such as Web Browsing.
6.3 . WAP stack
The WAP stack subsystem includes support for WAP 1.2.1 (WAP June 2000), push functionality and GPRS as a bearer. The WAP stack supports protocol specifications version 1.1 and 1.2.1 class C of the WAP Forum in connection-oriented mode. The WAP stack supports the following bearers: GSM CSD, GPRS UDP, CDMA and cdma2000 1x for connection-oriented browsing, GSM CSD, GPRS UDP, GSM SMS and GPRS SMS for connectionless push. The WAP 1.2.1, has the following layers:
¢ WSP, session protocol for WAP
¢ WTP, transaction protocol for WAP
¢ WTLS, transport layer security protocol for WAP
¢ WDP, datagram protocol for WAP, client and server
¢ a WAP push watcher which listens for secure and non-secure push messages received using connectionless mode over all supported bearers
7. MESSAGING
The messaging framework provides support for messaging protocols for sending and receiving of text messages (SMS), enhanced messages (EMS), multimedia messages (MMS), email and fax messages.
Main features of Messaging are:
7.1. Bearer Independent Object Messaging
Bearer Independent Object (BIO) Messaging allows application to application communication of arbitrary data types between devices. BIO messaging uses a watcher framework to support messages sent over-the-air to the operating system or application rather than to the end-user, for instance via SMS, MMS and email.
BIO message types currently supported include compact business card, vCard, vCalendar, email notification, operator logo, ring tone, and settings for internet access, MMS and WAP. The framework is open, allowing third parties to add further capabilities and value at run-time. The vCard and vCalendar BIO message file types are also supported over infrared and Bluetooth links.
7.2. Short Message Service (SMS)
SMS support consists of an SMS stack with a messaging API to send and receive SMS and provides the following features:
¢ the SMS stack is implemented as a plug-in protocol. The GSM (03.40) SMS protocol is provided
¢ the GSM SMS stack can be used as a bearer for the WAP protocol module
¢ transmission and reception of GPRS SMS
¢ SMS: send and receive streamed SMS messages. Enumerate, read, write and delete access to the SMS storage areas of the phone and SIM. Receive messages that match a specified text
¢ 7-bit SMS alphabet, 8-bit SMS alphabet and UCS2 data coding schemes are supported
¢ supports sending and receiving concatenated SMS messages
¢ scheduled sending: on a specific date/time, now or upon request. Specify and review scheduled actions.
7.3. Enhanced Messaging Service (EMS)
EMS support in Symbian OS is compliant with 3GPP release 4 (TS 23.040) and supports the following features:
¢ mobile originated pictures: variable picture, pre-defined picture: 16 x 16, pre-defined picture: 32 x 32
¢ mobile terminated pictures: variable pictures (1024x1 to 8x128), small pictures 16 x 16 and large pictures 32 x 32
¢ animations: pre-defined animations (multiple separate animations), black & white animations and mobile terminated user-defined animation
¢ Sounds: iMelody
¢ formatting: both mobile originated and terminated formatting, text size (small, medium, large), text style (bold, underline, strikethrough, italic) and message alignment (left, center, right).
7.4. Multimedia Messaging Service (MMS)
MMS operates over CSD and GPRS and provides the following features:
¢ both WSP and HTTP transports are supported. Messages are received over WSP Get or HTTP Get, and sent using WSP Post or HTTP Post
¢ message notification is received over WAP 1.2.1 Push or over HTTP by a similar push mechanism
¢ parameters supported include: Message-Type, MMS-Version, Date, From, To, Cc, Bcc, Subject, Message-Class (only personal), Expiry, Priority, Delivery-Report, Content-Type, Response-Status and Response-Text
¢ both Internet and MSIDSN addressing are supported, including mixed addressing
¢ message presentation is through SMIL 3GPP R5 (PSS 5). It is also possible to receive messages based on SMIL 1.0.
7.5. Email
Email has the following main features:
¢ Internet mail: supports disconnected mode, cache management, single operation get-new-mail for both POP3 and IMAP4, SMTP client enhancements (copy-to-self, separate emails for Bcc: send email for specific SMTP servers via specific ISP accounts, multiple SMTP connections with multiple send sessions), UUE and MIME, MHTML, automatic receipt notification, automatic MIME character set conversion, automatic email signature (or vCard). Character set conversion takes place during sending or receiving messages
¢ Internet access points (IAP): connection over GPRS is supported as well as over GSM CSD. Multiple IAPs, both GPRS and GSM CSD, can be associated with each email MTM to specify whether the default preferred connection or a specific connection should be used.
¢ secure socket connections: facility to establish a TLS socket connection to email servers.
7.6. Fax
The fax system interfaces to the messaging fax components at its upper boundary and to fax devices at its lower boundary. Fax supports the following features:
¢ fax class 1, 2 and 2.0 (ANSI/TIA/EIA 578 and ANSI/TIA/EIA 592), conforms to the ITU T.30 specification
¢ multiple recipient outgoing faxes
¢ ITU T.4 1D and 2D-encoding
¢ scheduling of sending: on a specific date, now or upon request. Specify and review scheduled actions.
8. MULTIMEDIA FRAMEWORK
The Multimedia Framework (MMF) provides a lightweight, multi-threaded framework for handling multimedia data. The framework provides audio recording and playback, audio streaming and image related functionality. Support is provided for video recording, playback and streaming.
The framework allows developers to write efficient and powerful plug-ins.
The main features are:
¢ generic multimedia plug-in system: plug-ins can be written using abstract and concrete classes that represent actual resources and abstract components. Concrete classes include files, descriptors, sockets, audio i/o, and video i/o
¢ the audio framework provides commonly used functionality including audio playback, audio recording, audio streaming and audio conversion, formats supported include WAV, AU, RAW (in various formats), PCM, uLaw, aLaw, GSM6.10 etc.; a codec API is provided and the framework supports codec plug-ins
¢ audio Controller plug-in; file, descriptor and microphone source plug-ins, and file, descriptor and speaker sink plug-ins
¢ sound device abstraction and arbitration
¢ video playback/recording/telephony framework
¢ MIDI client API
¢ concurrent processing of multiple multimedia data streams.
Image Conversion Library (ICL)
The image conversion library is a lightweight, optionally multithreaded, client-side framework for still image codecs and conversion; Plug-ins supplied by Symbian include JPEG, GIF, BMP, MBM, SMS, WBMP, PNG, TIFF, WMF and ICO. Third party plug-ins are enabled through the extensible nature of the framework.
Camera support
An onboard camera API providing a consistent interface to basic camera functions.
9. APPLICATION ENGINES
The core application engines include agenda (schedule), to-do, contacts, spreadsheet, alarm and world servers and the help engine.
Main features are:
¢ agenda engine: provides client-server shared access; vCalendar support with send and receive functionality; synchronization with PIM applications using Symbian Connect
¢ to-do engine: integrated with the agenda engine for storing agenda type entries
¢ contacts model: provides a generic client-server shared access contacts database engine, integrates with messaging application for emails, faxes and SMSs, caller number matching receive a vCard (supports Versit vCard 2.1 standard), group support, support for multiple templates, support for extensible field types, current item support, connectivity requirements, searching and filtering by contact item type
¢ sheet engine: spreadsheet support for multiple worksheets, rich text formatting for cells, borders and shading, many general, scientific, financial and statistical functions, formula evaluation and charts, added a power function
¢ chart engine: renders the graphics for a chart view of a spreadsheet application
¢ help engine: context sensitive help engine consisting of four parts, a launching mechanism, the model (which describes the database to its clients), the SQL search engine (capable of relational-like searches across all the tables in the database), and incremental facilities for use by the PC-based help file authoring system client
¢ text to Symbian OS Word converter: provides conversion between plain text and a Symbian OS Word model stream, and back again.
10. APPLICATION FRAMEWORK
The Application framework subsystem provides a powerful environment for licensees and partners to create differentiated user interfaces while enabling applications written in C++ and Java, by Symbian, licensees, partners and third parties to run seamlessly on open Symbian OS phones. This subsystem is architecturally central to the support of graphical user interface (GUI) applications. It includes a number of system-wide plug-in mechanisms for instantiating components at run-time, powerful reusable libraries for data, graphics and text support.
10.1. Graphical user interface (GUI) framework
A principal objective of the graphical user interface (GUI) framework is to define as little policy as possible and therefore minimize the constraints placed on a product's UI designer. This eases the porting of the user interface of applications between different Symbian OS phones.
Main features of the GUI framework:
¢ an event-driven GUI and widget architecture
¢ a windowing system for sharing screen, keyboard and pointer between applications; clocks and animated bitmaps, and a control framework for sharing an application window between application components
¢ direct navigation page link (DNL) system enables close task-based integration between applications
¢ a mechanism for the licensee to customize the look and feel (LAF) of the GUI.
¢ a plug-in mechanism for the user to input non-standard data (e.g., for ideogram input or voice recognition for phones that may not have a keyboard)
¢ control factory structure allows the framework to be extended by multiple applications
¢ a notifier framework allowing system events and alarms to be handled more flexibly by the GUI
¢ a flexible screen indicator and status bar framework
¢ runtime changeable color schemes
¢ bitmap animation performed in the Window Server thread.
10.2. Application support services
The application services are composed of components, primarily used by application engines, that provide core services:
¢ task scheduler: schedules launching of applications or initiation of specific application features.
¢ system agent: a general repository for system wide dynamic state informationlog engine: recording the use of any on-board devices (especially the phone)
¢ alarm server: alarm persistence, sound playing
¢ world server: country codes, world country and city information database
¢ calendar conversion between the Gregorian and the Chinese calendars
¢ support for Eastern-Asian character sets in vCard and vCalendar
10.3 Internationalization support
The main internationalization features are:
¢ conforms to the Unicode Standard version 3.0
¢ a framework to support European, Chinese, Arabic, Hebrew, Thai and Japanese locales
¢ a front-end processor (FEP) framework for text input using handwriting recognition or keyboard to enable input of far eastern ideographic characters. FEPs can take the form of a floating window, or a transparent window, or be invisible. They can also interact closely with their target controls, e.g. to do inline editing
¢ conversion between Unicode and other character sets, via a plug-in mechanism
¢ Support for rendering and editing bi-directional text; Support for drawing bi-directional text to graphics objects.
10.4 Various text and graphical utilities
Main other Application Framework features and utilities:
¢ rich text rendering for various locales, providing a text model with character and paragraph formatting, embedded graphics, and a text view which supports efficient formatting, display and interaction
¢ two multi-level undo/redo capabilities: a plain text undo system that can undo text insertion, deletion and clipboard operations, and a rich text undo system that can cope with anything a rich text object can do, including embedded objects
¢ generic support for plug-in parsers that recognize certain strings, eg URLs, email addresses, phone numbers. This enables to run services or applications from any application in the system
¢ support for PC-style changeable color schemes in editable text and for auto-sizing text editors
¢ background images: arbitrary graphics can be drawn behind text, with control of parameters like transparency and background scrolling.
11. PAN CONNECTIVITY
Personal Area Networking connectivity is available through support of Bluetooth, USB and infrared (IrDA).
Bluetooth support is provided with a core Bluetooth 1.1 protocol stack along with full Generic Access Profile (GAP), Generic Object Exchange Profile (GOEP) and Serial Port Profile implementations. The Host Controller Interface (HCI) provides a hardware interface via a UART based reference implementation. The OBEX implementation provides an OBEX v1.2 client and server that operate over Bluetooth and IrDA. The OBEX server also provides USB support.
USB class support is provided for the WMCDC WHCM and OBEX class, and for the CDC ACM class. All classes are controlled by a USB Manager component. All USB support is provided ultimately by a USB v1.1 client driver.
The infrared IrDA stack is contained in a socket server protocol module that implements the following IrDA layers: IrLAP v1.1, IrLMP v1.1 and IrTinyTP v1.1. The following features are supported:
¢ infrared (SIR) supporting throughputs of 9.6 KBPS to 115.2 KBPS
¢ IrOBEX v1.2 (IrDA object exchange)
¢ IrTRANP v1.0 digital camera picture infrared transfer protocol
¢ IrCOMM v1.0 supports fax/modem functionality and is implemented in a serial communications server module.
The infrared message type module integrates IrOBEX handling into the messaging framework.
12. BASE
The Base subsystem provides the programming framework for all other components of Symbian OS. Base provides an abstraction to facilitate design across multiple platforms and resources making it easier to port Symbian OS to new types of hardware. The Base ensures Symbian OS robustness, performance and efficient power management - all essential in a mobile phone. The main user-visible parts of the base are the user library and the file server.
12.1. Kernel and user library
The kernel runs in privileged mode, owns device drivers, implements the scheduling policy, does power management and allocates memory to itself and user-mode (that is, unprivileged) processes. It runs natively on ARM cores. The kernel implements a message-passing framework for the benefit of user-side servers (such as the networking and telephony stacks and the file system). The user library is the lowest-level user-mode code, which offers library functions to user-mode code, and controlled access to the kernel. Here are the main features:
¢ process, thread, program and memory management
¢ error handling and cleanup framework
¢ descriptors: strings of characters and buffers of binary data
¢ container classes: arrays and lists
¢ active objects, for event-driven multi-tasking without requiring the overheads of multi-threading
¢ client-server architecture, for simple and efficient inter-process communication. The client-server architecture supports both thread-relative and process-relative client resource ownership. The latter is to ease porting of code written for other platforms to Symbian OS, and delivers considerably enhanced Java performance
¢ a hardware abstraction layer (HAL) presenting a consistent interface to hardware across all devices
¢ a kernel-side power model, to allow fine-grained power management
¢ silent running mode: device can operate with screen switched off locale support including currency, time and date formatting
¢ internal and tightly-coupled RAM support
¢ the kernel can be extended by the use of DLLs (such as device drivers and kernel extensions) that can page link dynamically against the kernel.
12.2. Device drivers
The Base subsystem provides device drivers and/or software controllers for the following devices:
¢ DTE serial port
¢ DCE serial port
¢ infrared
¢ HWA (Driver implementing the hardware acceleration API for managing DSP hardware)
¢ USB client
¢ PC Cards
¢ MultiMediaCards (including support for password protected cards)
¢ SD Memory Cards
¢ LCD
¢ Keyboard
¢ Digitizer.
The majority of these are split into a logical layer component implementing the higher layer functionality common to all devices of that device type together with a physical layer component implementing the hardware specific functionality.
12.3. File server
The File server provides shared access to the filing systems, a client-side interface that hides the client-server architecture and a framework for dynamically mounting plug-in file systems, with physical storage of files associated with each filing system.
Main features:
¢ file system drivers can be added when required without having to reboot
¢ clients can register for notification of file-server events, for example, entries changing in given directory, changing disk or disk space crossing a specified threshold
¢ the VFAT file system supports a 'rugged' mode of operation which provides improved data integrity in machine power loss situations.
12.4. Standard library
Base also contains middleware widely used across Symbian OS. Here are the main ones:
¢ the C standard library
¢ a relational database access API. Two DBMS implementations are provided: a small and relatively lightweight client-side implementation; and, a client-server implementation for when multiple clients must have write access to a database.
¢ a stream store that defines two major abstractions: streams (an abstract interface to convert between an object's internal and external representations) and stores (an abstract interface to manipulate a network of streams).
13. SECURITY
The security subsystem enables data confidentiality, integrity and authentication by providing underlying support for secure communications protocols such as TLS/SSL, WTLS and IPSec. It also supports the authentication of installable software using digital signatures.
13.1. Cryptography module
The cryptography module includes the following significant components:
¢ cryptography algorithms allowing data to be encrypted and decrypted and supporting symmetric ciphers: DES, 3DES, RC2, RC4 and RC5, and asymmetric ciphers: RSA, DSA and DH
¢ hash functions: MD5, SHA1 and HMAC
¢ pseudo-random number generator for generating cryptographic keys.
13.2. Cryptography token framework
The cryptographic token framework enables licensees to integrate support for removable hardware devices, such as WIM modules, in a flexible manner. It consists of two parts:
¢ a framework which enables application code to query the system for the availability of implementations of specific cryptographic interfaces and their attributes (e.g., whether they are implemented in hardware, whether they are removable, whether they implement their own access control mechanism)
¢ the definition of a set of cryptographic interfaces. Licensees may supply their own implementations of any of the defined interfaces and these will be picked up by applications using the framework (so for example they may provide a WIM implementation which implements the certificate storage interface, and then certificates stored on the WIM will be visible in the certificate management application and available to the certificate validation module).
13.3. Certificate Management module
The certificate management module is used for authentication of other entities (e.g. third-party developers, web servers) to the user of the phone, and for authentication of the user of the phone. This module provides the following services:
¢ storage and retrieval of certificates using the cryptographic token framework
¢ assignment of trust status to a certificate on an application-by-application basis
¢ certificate chain construction and validation
¢ verification of trust of a certificate
¢ certificate revocation checking using the Online Certificate Status Protocol (OCSP).
13.4. Software installation
The software installation system provides a secure and fast installation process. The installation tool supports:
¢ installation of C++ executables, including authentication of software components using digital signatures to provide a
measure of confidence that applications being installed onto a Symbian OS phone are from a known reputable vendor
¢ installation of Java MIDP 2.0 MIDlets, including authentication of MIDlets using digital signatures
¢ installation of Java MIDP 1.0 MIDlets. The MIDP OTA recommended practice document is fully supported
¢ compression of install packages to reduce disk space and download times. The compression library is a generic shareable DLL which can be called by other applications
¢ different varieties of phones, allowing the installation package creator to ensure the correct software is installed onto an appropriate phone.
15. CONCLUSION
Symbian OS is a robust multi-tasking operating system, designed specifically for real-world wireless environments and the constraints of mobile phones (including limited amount of memory). Symbian OS is natively IP-based, with fully integrated communications and messaging. It supports all the leading industry standards that will be essential for this generation of data-enabled mobile phones. Symbian OS enables a large community of developers. The open platform allows the installation of third party software to further enhance the platform.
GLOSSARY
2.5G
In mobile telephony, 2.5G protocols extend 2G systems to provide additional features such as packet-switched connection (GPRS) and enhanced data rates (HSCSD, EDGE).
3G
In mobile telephony, third-generation protocols support much higher data rates, measured in Mbps, intended for applications other than voice. 3G networks trials started in Japan in 2001. 3G networks are expected to be starting in Europe and part of Asia/Pacific by 2002, and in the US later. 3G will support bandwidth-hungry applications such as full-motion video, video-conferencing and full Internet access
AMPS
Advanced Mobile Phone System: a 1G standard which operates in the 800-900MHz-frequency band. It is still widely used in the United States.
CLDC
J2ME Connected Limited Device Configuration. The CLDC serves the market consisting of personal, mobile, connected information devices. This configuration includes some new classes designed specifically to fit the needs of small-footprint devices.
DCS1800
Digital Communications System: another name for GSM working on a radio frequency of 1800 MHz. Also known as GSM1800 or PCN, this digital network operates in Europe and Asia Pacific.
EDGE
Enhanced Data Rates for GSM Evolution. An enhanced modulation technique designed to increase network capacity and data rates in GSM networks. EDGE should provide data rates up to 384 Kbps. EDGE will let operators without a 3G license to compete with 3G networks offering similar data services. EDGE is not expected before 2001 at the earliest.
EPOC
Deprecated term. Refer to Symbian OS.
PCN
Personal Communications Network: another name for GSM 1800 (it is also known as DCS 1800). It is used in Europe and Asia Pacific.
PDC
Personal Digital Cellular: the 2G TDMA-based protocols used in Japan, owned by NTT DoCoMo. PDC services operate in the 800 and 1500 MHz bands.
REFERENCES
Sites
1. symbian.com
2. outlook4mobility.com
3. linuxworld.com
4. programmersheaven.com
5. wirelessdvenet.com
Books
1. Symbian OS C++ for mobile phones by Richard Harrison
2. Symbian OS Communication Programming by Michael J. Jipping
3. Professional Symbian Programming: mobile solution on the EPOC Platform by Martin Tasker Et Al
4. Wireless Java for Symbian devices by Johnathan Allin
ACKNOWLEDGEMENTS
I express my sincere thanks to Prof. M.N Agnisarman Namboothiri (Head of the Department, Computer Science and Engineering, MESCE), Mr. Zainul Abid (Staff incharge) for their kind co-operation for presenting the seminars.
I also extend my sincere thanks to all other members of the faculty of Computer Science and Engineering Department and my friends for their co-operation and encouragement.
Sijo T.J.
CONTENTS
1. Introduction
2. Mobile Phone Core Platform
3. Hardware Access
4. Key features of Symbian
5. Telephony
5.1. GSM/EDGE Telephony
5.1.1. GSM
5.1.2. GPRS
5.1.3. EDGE
5.2. CDMA Telephony
5.2.1. CDMA (IS-95)
5.2.2. cdma2000 1x
6. Communication infrastructure
6.1. Networking
6.2. HTTP transport framework
6.2.1. HTTP client stack
6.3. WAP stack
7. Messaging
7.1. Bearer Independent Object Messaging
7.2. Short Message Service (SMS)
7.3. Enhanced Messaging Service (EMS)
7.4. Multimedia Messaging Service (MMS)
7.5. Email
7.6. Fax
8. Multimedia Support
9. Applications engines
10. Application framework
10.1. Graphical User Interface (GUI) framework
10.2. Application support services
10.3. Internationalization support
10.4. Various text and graphical utilities
11. Pan Connectivity
12. Base
12.1. Kernel and user library
12.2. Device drivers
12.3. File server
12.4. Standard library
13. Security
13.1. Cryptography module
13.2. Cryptography token framework
13.3. Certificate management module
13.4. Software installation
14. Conclusion
Glossary
References
