Mobile Device Operating Systems

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Mobile Device Operating Systems

• C203 3292
• jjc1_at_staffs.ac.uk

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Content

• Why use one at all ?
• What benefits do they give
• What losses!
• Widely used OSs in terms of devices
• Symbian
• Windows for Mobile
• PALM OS
• OS X
• Linux ???
• Proprietary

3
Device Technology

• An operating system is a piece of software which
  logically sits on top of the hardware and
  interfaces applications

User
Applications
OS
Device Driver
Hardware
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Device Technology

• OS Gives
• A common programming interface
• Allows communication with a piece of hardware
• i.e. the numeric pad
• We could communicate with the numeric pad
  directly but
• How do we deal with it if two applications are
  attempting to attach to the same piece of
  hardware?
• If both application are written by the same
  organisation then they will probably be written
  to deal with this
• If not then one will get control and the other
  will have to wait if this is written into the
  software if not it will crash or enter a loop
• A loop in terms of a PC is annoying and takes CPU
  time
• In a Mobile device this can be a disaster as this
  is taking CPU time and ultimately battery power!

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Device Technology
Application 1
Application 2
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Device Technology
Application 1
Application 2
Operating System
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Device Technology

• Most computing devices now use an operating
  system
• Due to a number of advantages
• What makes a Mobile OS different is the limited
  hardware
• Battery as a power source
• Limited processing capability
• Limited storage for the OS
• Limited memory
• Application and storage
• Storage memory can be upgraded
• Fixed hardware
• Or at least limited changes to this once released
• Telephony functionality needs to be available at
  all times
• Long term uptime
• How often does a user want to restart?
• Do you know how to restart your phone ?
• If the mobile device is in a remote location
• How often can it be restarted?

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Device Technology

• Common programming Interface
• This allows for hardware to change within device
  and a minimum of changes are required to release
  the OS
• Bring together the hardware for a wireless
  electric meter reader using a wireless LAN
• Now place the OS on the device and put all of the
  device drivers for this piece of hardware
• Create the application to send the message once a
  month
• Now three months into the development a new
  technology is released and your company decides
  to develop for it i.e. Zigbee
• Now all you do is change the device driver for
  your OS to the new technology
• The application remains the same with no changes
• Occasionally a change will be needed for your
  application in addition but the workload is a lot
  less than having to redo everything

9
Desktop OS

• The common Desktop and Laptop OSs
• Windows XP - Vista
• Apple OS X
• Linux
• These operating systems though are designed for
  devices which have a large capacity for storage

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Device Technology

• OS problems
• The major problem which OSs introduce on a small
  battery operated device is the overhead of
  storing and running this
• OS can require a large amount of storage
• Although most commonly they are now operated from
  ROM
• They do add another layer of communications
• They will take some of the limited memory for
  there operations
• There are scenarios were a OS is not required
  with very simple hardware that will provide
  information and is unlikely to change
• Example could be a small sensor node which
  provides feedback on water levels from a remote
  location

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Device Technology

• Core of the OS is referred to as the Kernel
• In mobile devices this is usually referred to as
  the Nano kernel
• Minimalist number of operations are required and
  used
• It is the Kernel which takes responsibly for
  controlling
• accesses to all hardware from applications
• Allocating memory and releasing it after
• And refusing it!
• If an application runs and this will effect the
  operations of the other applications it is better
  to refuse it
• Allowing multithreading on hardware
• Allowing for thread synchronisations

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Differences on a Mobile OS

• Symbian have given a list of 5 considerations for
  a mobile operating system
• http//gizmonaut.net/symbian/why_a_different_os.ht
  ml
• mobile phones are both small and mobile
• mobile phones are ubiquitous - the target is a
  consumer mass-market
• mobile phones are occasionally connected they
  can be used both when connected to the wireless
  phone network or locally to other devices, or on
  their own
• manufacturers need to differentiate their
  products in order to innovate and compete in a
  fast-evolving market
• the platform has to be open to enable independent
  technology and software vendors to develop
  third-party applications, technologies and
  services

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Device Technology

• Common OSs within the field of PDAs and Phones
  are
• Symbian
• Windows for Mobile
• PALM OS
• Other OSs though are developed and used for
  specific tasks
• Vxworks
• Used in the Mars Rover project
• Nasa Deep Impact project
• Boeing 787 aircraft

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Device Technology

• Operators can also use a proprietary OS
• This is developed for there own requirements
• All of the coding is done in house and only those
  people can make adjustments
• This has the advantage of control over the
  developments
• Everything has to go through the approval process
  to avoid introducing more problems that are being
  fixing
• Rather a open operating system
• Open systems can be adjusted and tailored to your
  needs by anyone with the source code
• Users feedback into the OS to give improvements
• Or fix and recognise bugs

15
Symbian

• Symbian is built upon the PSION EPOC
• EPOC widely accepted as standing for Electronic
  Piece Of Cheese
• Symbian is controlled by a number of companies
• Nokia
• Samsung
• Ericsson
• Sony
• Others as well
• http//www.symbian.com/
• It is a open source OS with developers having
  access to the code to adjust as required
• http//nds2.ir.nokia.com/NOKIA_COM_1/About_Nokia/P
  ress/White_Papers/pdf_files/symbian_net.pdf
• All applications have protected memory space
• So each application runs its own memory area
  which is requested at startup
• This prevent problems of a poorly programmed
  application effecting others

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Symbian

• Layered approach
• UI design
• Application Engine
• Ability to create user Interfaces to the System
  layer
• System Layer
• Gives the communications as in TCP, UDP, SMS
• Database Management
• Core
• Device Drivers
• Kernel
• EKA1 on pre 8.1 versions
• EKA2 on newer versions
• One major change was the ability to support
  multiple threads
• A single null thread always runs to control items
  power control
• Memory Management
• Here is a list of current phones which support
  Symbian
• http//www.symbian.com/phones/index.html

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Windows CE

• Microsoft mobile OSs
• Windows CE (Compact Edition)
• This gives a base set of functionality
• Based around portable devices
• These OSs are built upon Windows CE and give
  more specific functionality
• Pocket PC
• Windows for Mobile
• Windows for Smart Phone
• http//www.microsoft.com/windowsmobile/default.msp
  x
• Applications then sit on top of this

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Windows CE

• The latest edition is Windows CE 6
• This will support a maximum of 32,000 processes
• Each process can have a maximum virtual memory of
  2Gbytes
• The applications which are installed are also now
  pushed towards developments of wireless computing
• New software components are available for
  communications called Cell Core
• A lot more functionality has been put into the
  Kernel rather than having separate processes
• An example could be the file system or the device
  drivers

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Device Technology
http//www.windowsfordevices.com/files/misc/shared
source-history.jpg, 2007
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Apple OS

• Apple have entered the smart phone market
• With some obvious publicity
• The IPhone is based on Mobile OS X
• This is a cut down version of the OS X which is
  developed for the Apple MAC computers
• They have taken out all of the functionality
  which is not needed for a Mobile device
• An example is support for USB
• As the device does not have a port for this
• The exact size of the OS is not given
• Several sites though do list the size as 500
  Mbytes
• http//www.roughlydrafted.com/RD/RDM.Tech.Q1.07/69
  DDEC68-9E93-4A21-9C5F-F15F0D67F740.html

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GUI

• The Interfaces for the OSs looks quite similar

http//en.wikipedia.org/wiki/ImageWM50today.png
http//www.mobile-info.info/palmtero20650.jpg
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Software

• With the introduction though of standard OSs
• This has meant more software can be developed to
  use this functionality
• Popular programs are availble such as the
  Microsoft office suite
• Open Office for the Symbian
• In addition though there is software which is
  popular and useful on these devices which does
  not exist within the desktop environment
• Such as voice note taker
• TVRemote Controller
• The list is endless and is being developed
  continuously
• The fact that there are standard OSs allows the
  developer community to create new applications
  and try them to see if they are popular
• If they are not then something else can be
  developed

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Market Place

• Unlike the desktop market there is much more
  competition in the mobiles market place
• Here are the latest figures from
  http//developer.symbian.com/main/getstarted/newsl
  etter/MarketRoundUp/SymbianMarketRound-UpIssue2Oct
  07FINAL.pdf, 2007
• These figures are for SmartPhone devices not
  PDAs

Access OS
http//www.access-company.com/products/linux/alp.h
tml
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Market Place

• PDAs OS
• Market Share
• http//www.gartner.com/it/page.jsp?id506328, 2007

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Future

• The OSs which are attached to the device will
  continue to get more functionality as the devices
  do
• At the moment they are limited in terms of
  processing and power requirements
• Although they most likely will always have these
  limits relative to a desktop machine
• As new uses come to the devices and better uses
  of air interfaces, this will increase the use of
  better OSs
• Which one will become/remain dominant is
  difficult to see in the future
• From the innovation point of view it would be
  better if the market remained split between
  different operators
• From the application development point of view it
  would be better if the market decided on a single
  OS for everyone to devlop for

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Conclusion

• What we have looked at
• Why is a special OS needed
• Types of OS widely available
• Market share within the differing uses