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(An Autonomous Institution)


OS Assignment on


                                                                                                                                                                                                                                             Submitted by

                                                                            Suchita G. Achari: 2bv14is107

                                                                             Roll no                 : 160


Nowadays mobile technology is rapidly increasing technology in telecommunication sector and has impact on everyone’s life so much it has reduced the burden of work of people in one or the other way. It includes number of portable technology like personal digital assistants (PDA), global positioning system, laptops, palmtops etc. So for the management of increasing mobile technology, various operating systems came in the market.

Structure of a mobile operating system: Operating system of a mobile is a software platform in which application programs can run on the top on mobile devices such as smart phones, PDA’s, cell phones etc. On the bottom of applications OS libraries lies, this includes functions for manipulation of files, current time and date and other functionalities. Device drivers are the components used for interaction operating system with hardware devices. It is shown in the below diagram (fig 1).

                      Fig 1: Structure of a mobile operating system

In the following comparative analysis of different operating systems of mobile phones is discussed in this document.

 Android OS: This operating system is based on Linux kernel, developed by Google and later on by open handset alliance. Java is its native language and it supports more than hundred languages. It is an open source model. It provides the platform to run applications that can change the default launcher. It also supports for various third party applications to be installed, updated and removed by users. The libraries of Android OS disk storage, graphics etc. User interface is one of the most features of Android OS. Because user can easily interact with devices easily through touch interface. The response to the input of user is fast. Basically smart phones are based on battery. The applications are handled automatically by Android OS stored in memory of mobiles. If memory becomes low then system ends the processes which are not active, initiates from those processes which have been not active for a very long period. ARM is its hardware platform. The mobile applications are secured, because they run in an isolated area which does not provide the access to the rest of the system until request is explicitly provided by the users after installing the applications. It is used in different mobiles such as Vivo, Samsung, Zen, HTC etc.

The following are the few versions of Android OS:

 Cupcake        - version 1.5

 Donut            -version 1.6

 Éclair             -version 2.0-2.1

 Froyo             -version 2.2-2.2.3

 Gingerbread   -version 2.3-2..3.7

 Honeycomb    -version 3-3.2.6

 Ice cream sandwich  -version 4-4.0.4

 Jelly Bean        -version 4.1-4.3..1

 KitKat              -version 4.4-4.4.4

 Lollipop           -version 5-5.1.1

 Marshmallow   -version 6-6.0.1

 nougat               -version 7-7.1

Nougat is the most recent Android version which is released in August 2016.

Features of Android OS:

  Most of Android devices support Near Field Communication (NFC). I.e. it allows interaction of devices at shorter distances.

  It supports for an infrared transmitter so that users can have remote control over their devices.

  It supports multi touch.

  It supports multiple languages.

  It supports extra screen resolution.

  It supports automatic update of software.

  Removable battery and storage.

  Controlling mobile phones from computers.

Android OS has many advantages. Some of them are as follows:     

 It supports many applications to be run at the same period of time.

 Notification through SMS, mail is easy.

 Accessing of applications is easy.

 Programmers can make changes in OS because it is based on Linux kernel.

 Android OS automatically does the management of processes.

Processes on Android OS can have five different states.

1. Foreground process: The processes which are running currently will be foreground processes.

2. Visible process: These processes are not foreground processes but still we can see them.

3. Service process: We cannot be able to see these processes. The tasks of these processes will be running in background.

4. Background process: These processes are invisible to the users.

5. Empty process: These processes do not contain any data of applications.

 IPhone OS: This operating system is developed by Apple. It is expensive. C is its native language. It is a closed source model with open source components. Its kernel type is Hybrid kernel. It is also used in iPad, iPod touch. It provides very interactive user interface through multi touch and it provides virtual keyboard. Iphone released its first version in 2007. In the bottom of IPhone OS architecture there lays core OS layer, this includes cocoa, media layer etc. It is Mac kernel basis OS. It’s one of the most famous advantage is that any application cannot be able to change the memory of the kernel. Because of this advantage Iphone OS has a very strong protection for memory. Latest Iphone have few sensors such as proximity sensors, accelerometers which are used for the screen adjustment and for the controlling of games. Another feature of this OS is it supports built in fm/am radio which is disabled by default. Iphone 7 is the latest version of IPhone OS.

Fig 2: Structure of IPhone OS

At the top of the structure there lies cocoa touch which includes frameworks that helps for   application developers. After cocoa touch layer there comes media service layer that provides audio, video, graphics etc. At the bottom of the structure and top of hardware it has core OS layer which includes several services such as threads, memory management etc.

  Features of IPhone OS:

  It has the option of hiding stock apps.

  It has control center.

  Better battery.

  It supports Multi tasking.

  It has the feature of image stabilization which gives pictures clearly.

  It also supports optimization of storage.

 Windows phone 7 OS: This operating system is developed by Microsoft used in smart phones and mobile devices. C++ is its native language. Because of this support of C++ language it is easier to develop applications for more platforms very quickly. It is closed source model. Its kernel type is monolithic kernel. It features a user interface which has a great user interaction and it also provides virtual keyboard. It also provides ultimate capability of a system. It also supports for on-screen virtual keyboard through which users can input text. Windows phone 7 OS is a 32 bit OS and its architecture consists of two layers. I.e. user layer and kernel layer. There are two different file systems. .i.e. IMGFS for system files, and TexFAT for user files. 1 GB is reserved for virtual memory and 2 GB of memory is allocated to processes and 2 GB is for kernel. Windows phones have many API’s so that network connection to mobiles will be very fast. Windows Phone 7 OS does not support Office documents with security permissions. It is based on ARM hardware.

Following are the few versions of Windows phone 7 OS:

 Windows Phone 8     -version Windows Phone OS 8.0

 Windows Phone 7.5  -version Windows Phone OS 7.1

 Windows Phone 7     -version Windows Phone OS 7.0

      Window OS mobile phones came up with touch and without touch screens. It supports background multi tasking.

Features of windows phone 7 OS:

 It supports very friendly user interface.

 It has the control on hardware.

 Clear view of pixels.

 It supports multi core processor.

 BlackBerry OS: This operating system is developed by BlackBerry for blackberry line of smart phones and released by Research in Motion (RIM). It is written in C++ and supports other languages also (like UK English, US English etc). It is a closed source model. Its kernel type is Java virtual machine (JVM). It has a feature of multitasking (running more than one application at a same time) and supports specialized input devices which are obtained by BlackBerry to support use in its devices such as trackballs, track pad, and trackwheel. It can create background threads in order to avoid running severe tasks. This OS is popular because of some functions like ‘PUSH’ method (sending and receiving of internet e-mail), support of various wireless information services. It supports ARM (RISC) architecture. Basically BlackBerry OS don’t run applications regarding Android OS. Its’ one of the most popular feature is active frames in which users can access eight open apps on one screen. The memory of this OS can be classified into three parts. I.e.

  Application memory which can be expanded up to 128 MB for storing applications.

  Device memory which can be expanded up to 850 MB for storage of files.

  Memory card for additional storage of data.

One of the disadvantage of this type of memory management is that memory manager doesn’t release memory after applications are closed this causes devices to work slowly. In the time applications are not active background threads are allowed to active. It provides as many useful features as follows.

 Time shift camera.

 Active frames.

 Gaming applications.

     Many versions of BlackBerry OS have been released. E.g.: version 1.0, version 3.6, version 5, version 7.0, version 7.1.

 Symbian OS: It is developed by company named Psion. Till 2010 it was most widely used operating system then Android OS overtakes its position. It is a open source model so that applications will be developed by designers and it runs on ARM architecture. Symbian OS is a multithreaded OS; this allows third party developers to run many processes in the background. It doesn’t support real time scheduling for the processes of users. Symbian OS devices consume less amount of energy so that batteries last for a longer period of time. One of the major drawbacks of this OS is that it does not support automatic update of software. If any user wants to update software he/she have to purchase a new brand phone. Symbian OS offers less speed compare to other operating system like Android OS.

      All applications of this OS are built with the help of three classes. They are application class, document class, application user interface class. The structure of this OS is as follows (fig 3). The lowest layer which is reachable to users is the base layers that include the file server and user libraries, DBMS etc. The architecture of Symbian OS is a microkernel.




Fig 3: Layer structure of Symbian OS

    Few Characteristics of Symbian OS are as follows:

 It has an open application environment.

 It supports multi tasking.

 It is more robust.

 It supports flexible user interface.

 It is object oriented.

    Few features of Symbian OS are as follows:

1. Multi tasking can be implemented by Symbian OS without multi threading.

2. It is Non-preemptive (i.e. process will not get deleted until it finishes its execution), mutual exclusion codes are not needed.

3. It supports java, hardware (CPU, types of memory etc) and real time applications.

4. It is rich in application services that include messaging, browsing etc.

    Four development kits o Symbian OS are as follows:

  Symbian OS Customization Kit.

  Symbian OS Development Kit.

  Symbian OS Binary Access Kit.

  Symbian OS Technology Preview SDK.


 Palm OS: It is also known as Garnet OS. It is developed by Palm inc., basically for handheld devices. It is built to run small product programs for devices that have small number of applications. It supports only a single application to run at a time. It must complete the processing of current application which is running, then have to start with new application.

  The following are the list of features of Palm OS:

  It does not supports multiprocessing, it only supports single processing.

  Memory is reserved for programs; it supports multiple storage for applications and data.

  Supports for CDMA/GSM.

  It is efficient and provides good Performance.

  It supports best hardware integration.

Number of chunks makes memory in which maximum size of each chunk is 64 KB and each chunks starts with 8 byte header followed by data. Each chunk has their size which is larger than actual size that has requested by applications. Memory chunks can be of two types: pointers and handles. It has 96 KB of total Dynamic Memory Area. Few of its versions are Garnet 5.4.9, Palm 5.4, Palm 5.4.5, Palm 5.4.8, etc.

    Tasks regarding Memory manager are as follows:

  It performs in allocation of new chunks.

  It disposes chunks.

  It can resize memory chunks

  It can lock and unlock chunks.

    Data manager main tasks are as follows:

  Each record in a database has a relation with chunks of memory.

  Each chunk is addressed by a local ID.

  Each record in a database is accessed by storing the local ID.


    Deficiencies of Palm OS:

 It does not support multi tasking. So it has the facility to run a sub application within applications.

 Because of the reason that Palm OS is not for real time applications, it does not provide a platform for running multimedia applications.

 It does not correspond to different types of hardware.

 Some of examples of standard applications are listed as below:

 To store contact information it has Address.

 To  view weekly, daily, monthly schedule it has Date Book

 To save events and event location it has Calendar.

 To save important notes it has Memos.

 For users to create personal remainders it has To do list.

      Tasks regarding Process Management of Palm OS are as follows:

 The system is event or interrupt driven.

 Processes will only begins if they receives an input event that call them

 The process runs till its execution is over otherwise it will enter into infinite loops.

The following table shows the comparative analysis of several OS’s discussed in this document.

Feature IPhone OS Android OS Windows phone OS BlackBerry OS

Company Apple inc. Open Handset Alliance

Microsoft BlackBerry Ltd.

Market share 14.8 % 84.1% 0.7% 0.2%

Current version 10.0.2 7.0 10.0.14393.189

OS family Darwin Linux Windows phone ONX

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