Chapter 02 - 03 Introducing Symbian OS

8/6/2019 Chapter 02 - 03 Introducing Symbian OS

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The Basics of Symbian OS Communication

ICT 3213 Mobile Operating System

FOEIT INTI International University


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Six elements that combine to makeup Symbian OS

The core OS, commonly called a kernel

[a bridge between application and actual data processing done at the hardware level]

A collection ofmiddleware for system services

[Software that provide a link between separate applications]

A set of resource managers, called application engines

A framework for designing user interfaces

Methods for synchronization with other machines

A Java virtual machine implementation

The Software:

Kernel- responsible for managing the systems resources

Middleware- connects software components or applications; facilitates applications such as security, web browsing,

messaging, etc

Application execution environment- application programming interfaces that allow developers to create their own

programs

User interface framework- graphics and layouts

Application suite-basic applications that users access regularly


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System view of SymbianOS(Framework)


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Architecture[Symbian/Android Architecture]

Kernel Services& HardwareInterfaces

Base Services

OS Services

Application

Services

UIFramework

Kernel Architecture

ConnectivityServices

Generic OSServices

Multimedia& GraphicServices

Comms FrameworkTelephony ServicesShort Link ServicesNetworking Services

Java J2ME

Low Level Libraries File Server


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Kernel Services & Hardware Interface..

Bootstraps[area forbootingpurpose] the physicalor emulated device

Provides physical andlogical device drivers

and other hardwareabstraction

Creates and managesthe fundamental OSkernel abstractions

In term of Processes, memory

management, scheduling,interrupts, communication linketc.

Kernel Architecture

Connectivity

Services

GenericOS

Services

ultimedia

GraphicService

s


Java J2

E

Kernel layer, contains the OSkernel itself, device drivers, andsimilar low-level components


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Base Services..

It includes the File Server and User Library: C++ Classes, native type Plug-In Framework which manages all plug-ins: Power Mgmt Store : Central Repository, DBMS Cryptographic services Services for a functional port

Kernel Architecture

Connectivity

Services

GenericOS

Services

Multimedia

GraphicService

s


Java J2ME

Lowest level of user-side services, extendsthe OS kernel into a useable (but minimal)system [drivers library located here]


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OS Services.. Extends the "base" into a fully

functional OS providing servicesacross a full range oftechnologies, e.g. graphics &multimedia, Communications,Connectivity, etc.

Generic: certificate mgmt

Communications:Bluetooth,Infrared, USB, TCP/IP, Wi-Fi

Connectivity: backup&restore, filetransfer, file browsing, etc.

Kernel Architecture

Connectivity

Services

GenericOS

Services

ultimedia &

GraphicService

s


Java J2

E

Generic OSServices

iddleware" layer of Symbian OS, fullrange of servers, frameworks, and

libraries[now is high level ] which extendthe base system into a complete OS[where it provides framework &libraries that extends into acomplete OS]

Multimedia &GraphicsServices

ConnectivityServices


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Application Services..

UI independentsupport forapplications, including basic

applicationframeworks/services

application class(technology-specific) logic

support for specificapplications.

Also someapplication enginesused and extended

by licensees

Kernel Architecture

Connectivity

Services

GenericOS

Services

ultimedia

GraphicService

s


Java J2

E

Generic - text rendering, MIME contenthandling, etc.Application specific plug-ins forcontacts, agenda, Word, Sheet, etc.Technology-specific - vCard, VCal, etc.


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Frameworks andlibraries forconstructing a UI

Includes the basicclass hierarchies forUI controls

Concrete widget

classes used by UIcomponents

Other frameworks andutilities

Kernel Architecture

Connectivity

Services

GenericOS

Services

ultimedia

GraphicService

s


Java J2

E

Topmost layer of Symbian OS,foundation for variant UI

UI Framework..


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Java J2ME MIDP..

Spans the UIFramework andApplication Services

layers Java implementation

based on J2ME MIDP2.0 and CLDC 1.1

Optional packages: 3Dgrahics, web services,file system access, etc.

Java J2MEMIDP 2.0 and CLDC 1.1


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Key Characteristics

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 interoperabilityWith a flexible and modular implementation, Symbian OS provides a core set of application programminginterfaces (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

processesFully Object-oriented and component based

The operating system has been designed from the ground up with mobile devices in mind, using advancedOO 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 isable 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 partydevelopers .


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Client-Server Architecture In Symbian OS, clients are programs that have user interfaces, and servers are programs that

can only be accessed via a well defined interface from other programs Event Management

Event management has long been considered core strength of Symbian OS - reflecting the factthat Symbian OS was designed from the start to have event based time sharing in a single thread

Object Oriented Design Because Symbian OS has an object oriented design, it is easy to configure for different sorts of

hardware, and being component based, itallows manufacturers to add or remove components This will provide a stable base as the telecommunications industry moves from 2G to 2.5G to 3G

to 4G, with the further introduction of new technologies such as SyncML, BlueTooth, andMultimedia Messaging amongst many

Power Management Symbian OS users are used to the performance of mobile phones - and so demand similar

performance in terms of weight and operating times when they adopt new devices Power management is built into the kernel of Symbian OS and is designed to make efficient use

of the processors and peripherals and so minimize power usage Robust and Dependable

Devices should not lose user data, crash or require rebooting Symbian achieves this in two ways:

Each process runs in a protected address space, thus it is not possible for one application tooverwrite anothers address space. The kernel also runs in a protected address space, sothat a bug in one application cannot overwrite the kernels stack or heap.


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Robust and Dependable Symbian achieves this in two ways:

The client-server architecture of Symbian OS allows applications to exchange datawithout compromising overall system integrity. This meets the requirement to work onstand alone portable devices, even though Symbian devices offer greatly enhancedfunctionality over standard mobile phones.

Memory Management

For stand alone portable devices, memory management is important The need to minimize weight, device size and costmeans the amount of memory available

on a Symbian OS device is often quite limited

Symbian OS always assumes that the memory available is limited, and minimizesconsumption at every turn

Consequently, less memory is actually required by the system also having less memory helpsto keep down power consumption

Full Multitasking

Symbian OS runs each application as a separate process, allowing multiple applications to runconcurrently

An Open Operating System

Symbian OS is an open OS

Open to anyone to license

Open to anyone to develop application

Based on open standards

Owned by the industry


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Memory Management

The absence of demand-paged virtual memory does not mean the absence of memory management,

smaller platforms are built on hardware that includes many of the management features of larger

systems

Execution in-place

Platforms with no disk drives usually support execution in-place

Flash memory is mapped into the virtual address space and programs can be executed directly from

flash memory, without copying them into RAM first

No Virtual Memory

The only storage available to the operating system on these platforms is memory; they do not come

with a disk drive

Smaller systems, from PDAs to smartphones to higher level handheld devices, do not support a

demand paged virtual memory


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Ans:


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4) Explain how Symbian operating system addresses the memory.

Ans:

How Symbian OS Addresses Memory?

Symbian OS is a 32-bit operating system, addresses can range up to 4 GB

Symbian OS divides memory into virtual pages and physical frames

Symbian OS adopts a two-level page table strategy (shown in next slide)

Chapter 02 - 03 Introducing Symbian OS

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