Programming mobile devices Part II Programming Symbian devices with Symbian C++

Practical matters Lectures Excercices (labs) Exam –Second midterm –Final exam The course project

Content The Smart phone environment Basics of the Symbian OS Differences between C++ and Symbian C++ What a Java programmer should know What a C++ programmer should know Memory management Symbian User Interfaces

Content Controls Dialogs Views Files, the filesystem Communication and Messaging Testing, debugging and deploying

The smart phone environmet 1G, 2G, 2,5G, 3G, 4G GSM Global System for Mobile Comm. CDMA (USA) Code Division Mult. Acc. CSD Circuit Switched Data (GSM Data) GPRS General Packet Radio Service HSCSD High Speed CSD EDGE Enhanced Data Rates for GSM Evolution

The smart phone environmet UMTS Universal Mobile Telecommunication Services -> 2 Mbps SMS, MMS, , Fax, Web (HTML), WAP IrDA, Bluetooth, USB NFC, RFID, ZigBee

Symbian OS Most common OS in devices like mobile phones Strong influence from device manufacturers Series (60,80,90) platforms Programmable with a C++ like language Also Java with a JRE Others: Palm OS, Microsoft Windows Mobile, Linux

Symbian architecture Kernel Base Libraries Application services, engines and protocols Application framework Communication architecture Middleware feature libraries

Symbian architecture Kernel system memory program scheduling resource allocation privileged CPU access

Symbian architecture Base Libraries APIs for basic computing, like string manipulation file IO db management...

Symbian architecture Application services, engines and protocols Application data, such as the phone book Devices services, such as alarms etc. Access to protocols, such as HTTP

Symbian architecture Application framework GUI Communications architecture TCP/IP, IrDA, BT, SMS, etc. Middleware feature libraries The rest of the bunch, such as security

Multitasking Threads –pre-emptive –single program can have several threads Processes –.exe –a main thread –threads share the same memoryspace

DLLs Dynamic Link Libraries Static interface DLLs –"traditional" shared functions Plymorphic DLLs –plug-ins, e.g. device drivers No static data (until OS v.9.0) –Conserves memory which the static variables would consume

Client/Server model basic concept in Symbian Example: file access C/S concept hidden by the API Server: –No UI –Waits for requests and serves clients by processing those requests.

Memory ROM –OS Software –cannot be written, but can be partly read RAM –volatile, usually up to 30 MB Internal Flash –disk drive type of memory (C:) Memory Cards –extendable, up to 1 GB (D:)

Addressing Memory Two types of memory addresses: virtual and physical -> mapping. MMU (Memory Management Unit) chunks (virtually addressed pieces of memory, not allways backed with physical memory) –stack and heap –static –code

Stack and heap Stack –automatic variables –class members Heap –new

Addressing Memory Two areas for memory: Home area and Run area. Process data of a running process is in the run area. Applications cannot reference memory in the home area Protects process memory Exception: fixed processes (OS-level)

The Kernel Creation and scheduling of processes and threads Communication between threads and processes (mutexes, semaphores) System memory Access to device hardware

The Kernel HAL (Hardware Abstraction Layer) Most code hardware independent Loading and communicating with device drivers User library: A DLL that provides access to kernel functions (privileged mode)

The Kernel Two main components: Executive and Server Functions executed by server have access to all global data of the kernel However, they are slow Functions executed by the executive are faster The reason: memory mapping