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, Email, 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