Jump to content

Symbian OS

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by 82.33.205.162 (talk) at 14:13, 8 September 2009 (→‎See also). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Symbian OS
Symbi OS logo
DeveloperSymbi Foundation (formerly Symbian Ltd.).
OS familyEmbedded operating systems
Working stateHistoric - is code base for Symbian
Source modelOriginally closed source, moving to open source
Latest releasev9.4 (Symbian^1) / unknown
Marketing targetMobile devices
PlatformsARM, [86 architecture
Kernel typeMicrokernel
Default
user interface		S60 platform, UIQ, MOAP
LicenseOriginally proprietary, moving to Eclipse Public License
Official websitewww.symbian.com

Symbian OS was designed for mobile devices, with associated libraries, user interface, frameworks and reference implementations of common tools, developed by Symbian Ltd. It was a descendant of Psion's EPOC and runs exclusively on ARM processors, although a non-productized x86 port existed.

In 2008 a new, independent non-profit organisation called the Symbian Foundation was established and the former Symbian Software Limited was acquired by Nokia. Symbian OS and its associated user interfaces S60, UIQ and MOAP(S) were contributed by their owners to the foundation with the objective of creating the Symbian platform as royalty-free, open source software. The process of publishing the source code under the Eclipse Public License (EPL) was slated for completion in 2010.[2]

The term 'Symbian OS' went out of current use with the advent of the Symbian platform, however the software itself, as described in this entry, did not.

Design

Symbian features pre-emptive multitasking and memory protection, like other operating systems (especially those created for use on desktop computers). EPOC's approach to multitasking was inspired by VMS and is based on asynchronous server-based events.

Symbian OS was created with three systems design principles in mind:

  • the integrity and security of user data is paramount,
  • user time must not be wasted, and
  • all resources are scarce.

To best follow these principles, Symbian uses a microkernel, has a request-and-callback approach to services, and maintains separation between user interface and engine. The OS is optimized for low-power battery-based devices and for ROM-based systems (e.g. features like XIP and re-entrancy in shared libraries). Applications, and the OS itself, follow an object-oriented design: Model-view-controller (MVC).

Later OS iterations diluted this approach in response to market demands, notably with the introduction of a real-time kernel and a platform security model in versions 8 and 9.

There is a strong emphasis on conserving resources which is exemplified by Symbian-specific programming idioms such as descriptors and a cleanup stack. There are similar techniques for conserving disk space (though the disks on Symbian devices are usually flash memory). Furthermore, all Symbian programming is event-based, and the CPU is switched into a low power mode when applications are not directly dealing with an event. This is achieved through a programming idiom called active objects. Similarly the Symbian approach to threads and processes is driven by reducing overheads.

The Symbian kernel (EKA2) supports sufficiently-fast real-time response to build a single-core phone around it—that is, a phone in which a single processor core executes both the user applications and the signalling stack. This is a feature which is not available in Linux. This has allowed Symbian EKA2 phones to become smaller, cheaper and more power efficient than their predecessors [citation needed].

Competition

Symbian is the leading OS in the "smart mobile device" market. Statistics published in November 2008 showed that Symbian OS had a 46.6% share of the smart mobile devices shipped in third quarter of 2008, with Apple having 17.3% (through iPhone OS), RIM having 15.3% and Microsoft having 13.5% (through Windows CE and Windows Mobile).[3] Other competitors include Palm OS, Qualcomm's BREW, Google Android, SavaJe and MontaVista Software.

Structure

The Symbian System Model contains the following layers, from top to bottom:

  • UI Framework Layer
  • Application Services Layer
    • Java ME
  • OS Services Layer
    • generic OS services
    • communications services
    • multimedia and graphics services
    • connectivity services
  • Base Services Layer
  • Kernel Services & Hardware Interface Layer

The Base Services Layer is the lowest level reachable by user-side operations; it includes the File Server and User Library, a Plug-In Framework which manages all plug-ins, Store, Central Repository, DBMS and cryptographic services. It also includes the Text Window Server and the Text Shell: the two basic services from which a completely functional port can be created without the need for any higher layer services.

Symbian has a microkernel architecture, which means that the minimum necessary is within the kernel to maximise robustness, availability and responsiveness. It contains a scheduler, memory management and device drivers, but other services like networking, telephony and filesystem support are placed in the OS Services Layer or the Base Services Layer. The inclusion of device drivers means the kernel is not a true microkernel. The EKA2 real-time kernel, which has been termed a nanokernel, contains only the most basic primitives and requires an extended kernel to implement any other abstractions.

Symbian is designed to emphasize compatibility with other devices, especially removable media file systems. Early development of EPOC led to adopting FAT as the internal file system, and this remains, but an object-oriented persistence model was placed over the underlying FAT to provide a POSIX-style interface and a streaming model. The internal data formats rely on using the same APIs that create the data to run all file manipulations. This has resulted in data-dependence and associated difficulties with changes and data migration.

There is a large networking and communication subsystem, which has three main servers called: ETEL (EPOC telephony), ESOCK (EPOC sockets) and C32 (responsible for serial communication). Each of these has a plug-in scheme. For example ESOCK allows different ".PRT" protocol modules to implement various networking protocol schemes. The subsystem also contains code that supports short-range communication links, such as Bluetooth, IrDA and USB.

There is also a large volume of user interface (UI) Code. Only the base classes and substructure were contained in Symbian OS, while most of the actual user interfaces were maintained by third parties. This is no longer the case. The three major UIs - S60, UIQ and MOAP - were contributed to Symbian in 2009. Symbian also contains graphics, text layout and font rendering libraries.

All native Symbian C++ applications are built up from three framework classes defined by the application architecture: an application class, a document class and an application user interface class. These classes create the fundamental application behaviour. The remaining required functions, the application view, data model and data interface, are created independently and interact solely through their APIs with the other classes.

Many other things do not yet fit into this model – for example, SyncML, Java ME providing another set of APIs on top of most of the OS and multimedia. Many of these are frameworks, and vendors are expected to supply plug-ins to these frameworks from third parties (for example, Helix Player for multimedia codecs). This has the advantage that the APIs to such areas of functionality are the same on many phone models, and that vendors get a lot of flexibility. But it means that phone vendors needed to do a great deal of integration work to make a Symbian OS phone.

Symbian includes a text based user-interface layer called "TechView". It provides a basis for starting customisation and is the environment in which much Symbian test and example code runs. It is very similar to the user interface from the Psion Series 5 personal organiser and is not used for any production phone user interface.

History

Psion

In 1980, Psion was founded by David Potter.

EPOC

Osaris PDA by Oregon Scientific with EPOC operating system

EPOC is a family of graphical operating systems developed by Psion for portable devices, primarily PDAs. EPOC came from epoch, the beginning of an era, but was backfitted by the engineers to "Electronic Piece Of Cheese".[4]

EPOC16

EPOC16, originally simply named EPOC, was the operating system developed by Psion in the late 1980s and early 1990s for Psion's "SIBO" (SIxteen Bit Organisers) devices. All EPOC16 devices featured an 8086-family processor and a 16-bit architecture. EPOC16 was a single-user pre-emptive multitasking operating system, written in Intel 8086 assembler language and C and designed to be delivered in ROM. It supported a simple programming language called OPL and an IDE called OVAL. SIBO devices included the: MC200, MC400, Series 3 (1991-1998), Series 3a, Series 3c, Series 3mx, Siena, Workabout and Workabout mx. The MC400 and MC200, the first EPOC16 devices, shipped in 1989, and as of September 2007, the Workabout mx is still in production.

EPOC16 featured a primarily 1-bit, keyboard-operated graphical interface (the hardware for which it was designed did not have pointer input).

In the late 1990s the operating system was referred to as EPOC16 to distinguish it from Psion's then-new EPOC32 OS.

EPOC32

The first version of EPOC32, Release 1 appeared on the Psion Series 5 ROM v1.0 in 1997. Later, ROM v1.1 featured Release 3 (Release 2 was never publicly available.) These were followed by the Psion Series 5mx, Revo / Revo plus, Psion Series 7 / netBook and netPad (which all featured Release 5).

The EPOC32 operating system, at the time simply referred to as EPOC, was later renamed Symbian OS. Adding to the confusion with names, before the change to Symbian, EPOC16 was often referred to as SIBO to distinguish it from the "new" EPOC. Despite the similarity of the names, EPOC32 and EPOC16 were completely different operating systems, EPOC32 being written in C++ from a new codebase with development beginning during the mid 1990s.

EPOC32 was a pre-emptive multitasking, single user operating system with memory protection, which encourages the application developer to separate their program into an engine and an interface. The Psion line of PDAs come with a graphical user interface called EIKON which is specifically tailored for handheld machines with a keyboard (thus looking perhaps more similar to desktop GUIs than palmtop GUIs [1]). However, one of EPOC's characteristics is the ease with which new GUIs can be developed based on a core set of GUI classes, a feature which has been widely explored from Ericsson R380 and onwards.

EPOC32 was originally developed for the ARM family of processors, including the ARM7, ARM9, StrongARM and Intel's XScale, but can be compiled towards target devices using several other processor types.

During the development of EPOC32, Psion planned to license EPOC to third-party device manufacturers, and spin off its software division as Psion Software. One of the first licensees was the short-lived Geofox, which halted production with less than 1,000 units sold. Ericsson marketed a rebranded Psion Series 5mx called the MC218, and later created the EPOC Release 5.1 based smartphone, the R380. Oregon Scientific also released a budget EPOC device, the Osaris (notable as the only EPOC device to ship with Release 4).

In June 1998, Psion Software became Symbian, a major joint venture between Psion and phone manufacturers Ericsson, Motorola, and Nokia. As of Release 6, EPOC became known simply as Symbian OS.

EPOC OS Releases 1–3

Work started on the 32-bit version in late 1994. The Series 5 device, released in June 1997, used the first iterations of the EPOC32 OS, codenamed "Protea", and the "Eikon" graphical user interface.

EPOC Release 4

Oregon Scientific Osaris

EPOC Release 5

The Psion Series 5mx, Psion Series 7, Psion Revo, Diamond Mako, Psion netBook, netPad, GeoFox One, and Ericsson MC218 were released in 1999 using ER5. A phone project was announced at CeBIT, the Phillips Illium/Accent, but did not achieve a commercial release. This release has been retrospectively dubbed Symbian OS 5; it was never called that at the time.

ER5u

The first phone, the Ericsson R380 was released using ER5u in November 2000. It was not an 'open' phone – software could not be installed. Notably, a number of never-released Psion prototypes for next generation PDAs, including a Bluetooth Revo successor codenamed Conan were using ER5u. The 'u' in the name refers to the fact that it supported Unicode.

Symbian OS v6.0 and 6.1

The OS was renamed Symbian OS and was envisioned as the base for a new range of smartphones. This release sometime is called ER6. Psion gave 130 key staff to the new company and retained a 31% shareholding in the spun-out business.

The first 'open' Symbian OS phone, the Nokia 9210 Communicator, was released in June 2001. Bluetooth support was added. Almost 500,000 Symbian phones were shipped in 2001, rising to 2.1 million the following year.

Development of different UIs was made generic with a "reference design strategy" for either 'smartphone' or 'communicator' devices, subdivided further into keyboard- or tablet-based designs. Two reference UIs (DFRDs or Device Family Reference Designs) were shipped – Quartz and Crystal. The former was merged with Ericsson's 'Ronneby' design and became the basis for the UIQ interface; the latter reached the market as the Nokia Series 80 UI.

Later DFRDs were Sapphire, Ruby, and Emerald. Only Sapphire came to market, evolving into the Pearl DFRD and finally the Nokia Series 60 UI, a keypad-based 'square' UI for the first true smartphones. The first one of them was the Nokia 7650 smartphone (featuring Symbian OS 6.1), which was also the first with a built-in camera, with VGA (0.3 Mpx = 640×480) resolution.

Despite these efforts to be generic, the UI was clearly split between competing companies: Crystal or Sapphire was Nokia, Quartz was Ericsson. DFRD was abandoned by Symbian in late 2002, as part of an active retreat from UI development in favour of 'headless' delivery. Pearl was given to Nokia, Quartz development was spun off as UIQ Technology AB, and work with Japanese firms was quickly folded into the MOAP standard.

Symbian OS 7.0 and 7.0s

First shipped in 2003. This is an important Symbian release which appeared with all contemporary user interfaces including UIQ (Sony Ericsson P800, P900, P910, Motorola A925, A1000), Series 80 (Nokia 9300, 9500), Series 90 (Nokia 7710), Series 60 (Nokia 3230, 6260, 6600, 6670, 7610) as well as several FOMA phones in Japan. It also added EDGE support and IPv6. Java support was changed from pJava and JavaPhone to one based on the Java ME standard.

One million Symbian phones were shipped in Q1 2003, with the rate increasing to one million a month by the end of 2003.

Symbian OS 7.0s was a version of 7.0 special adapted to have greater backward compatibility with Symbian OS 6.x, partly for compatibility between the Communicator 9500 and its predecessor the Communicator 9210.

In 2004, Psion sold its stake in Symbian. The same year, the first worm for mobile phones using Symbian OS, Cabir, was developed, which used Bluetooth to spread itself to nearby phones. See Cabir and Symbian OS threats.

Symbian OS 8.0

First shipped in 2004, one of its advantages would have been a choice of two different kernels (EKA1 or EKA2). However, the EKA2 kernel version did not ship until Symbian OS 8.1b. The kernels behave more or less identically from user-side, but are internally very different. EKA1 was chosen by some manufacturers to maintain compatibility with old device drivers, while EKA2 was a real-time kernel. 8.0b was deproductized in 2003.

Also included were new APIs to support CDMA, 3G, two-way data streaming, DVB-H, and OpenGL ES with vector graphics and direct screen access.

Symbian OS 8.1

Basically a cleaned-up version of 8.0, this was available in 8.1a and 8.1b versions, with EKA1 and EKA2 kernels respectively. The 8.1b version, with EKA2's single-chip phone support but no additional security layer, was popular among Japanese phone companies desiring the real-time support but not allowing open application installation. The first and maybe the most famous smartphone featuring Symbian OS 8.1a was Nokia N90 in 2005, Nokia's first in Nseries. It comes with Carl-Zeiss Tessar optics and a 2 Mpx (1600*1200) camera with video capabilities to take VHS quality (352×288) videos and a huge screen resolution (at the time) of 352*416 pixels.

Symbian OS 9.0

This version was used for internal Symbian purposes only. It was de-productised in 2004. 9.0 marked the end of the road for EKA1. 8.1a is the final EKA1 version of Symbian OS.

Symbian OS has generally maintained reasonable binary code compatibility. In theory the OS was BC from ER1-ER5, then from 6.0 to 8.1b. Substantial changes were needed for 9.0, related to tools and security, but this should be a one-off event. The move from requiring ARMv4 to requiring ARMv5 did not break backwards compatibility.

A Symbian developer proclaims that porting from Symbian 8.x to Symbian 9.x is a more daunting process than Symbian says.[5]

Symbian OS 9.1

Released early 2005. It includes many new security related features, particularly a controversial platform security module facilitating mandatory code signing. Symbian argues that applications and content, and therefore a developer's investment, are better protected than ever; however others contend that the requirement that every application be signed (and thus approved) violates the rights of the end-user, the owner of the phone, and limits the amount of free software available. The new ARM EABI binary model means developers need to retool and the security changes mean they may have to recode. S60 platform 3rd Edition phones have Symbian OS 9.1. Sony Ericsson is shipping the M600 and P990 based on Symbian OS 9.1. The earlier versions had a fatal defect where the phone hangs temporarily after the owner sent hundreds of SMS'es. However, on 13 September 2006, Nokia released a small program to fix this defect.[6]

Support for Bluetooth 2.0 (was 1.2)

Symbian OS 9.2

Released Q1 2006. Support for OMA Device Management 1.2 (was 1.1.2). Vietnamese language support. S60 3rd Edition Feature Pack 1 phones have Symbian OS 9.2. Nokia phones with Symbian OS 9.2 OS: Nokia E90, Nokia E66, Nokia E63, Nokia E71, Nokia E51, Nokia N95, Nokia N82, Nokia N81, Nokia 6290, Nokia 6120 classic, Nokia 5700, SGH L870.

Symbian OS 9.3

Released on 12 July 2006. Upgrades include improved memory management and native support for Wifi 802.11, HSDPA. The Nokia E72, Nokia E52, Nokia E55, Nokia N78, Nokia N79, Nokia N85, Nokia N86 8MP, Nokia N96, Samsung GT-i8510 and others feature Symbian OS 9.3.

Symbian OS 9.4

Announced in March 2007. Provides the concept of demand paging which is available from v9.3 onwards. Applications should launch up to 75% faster. Additionally, SQL support is provided by SQLite. Ships with the Samsung i8910, Nokia N97 and Nokia 5800 XpressMusic. Used as the basis for Symbian^1, the first Symbian platform release.

Symbian OS 9.5

Includes native support for mobile digital television broadcasts in DVB-H and ISDB-T formats and also location services.

Open source software for Symbian 9.1

Open source software for Symbian is available[7][8] and following software has been ported or rewritten for Symbian 9.1:

Utilities

Game emulation

Multimedia

  • OggPlay – Audio player with ogg vorbis audio format support

Frameworks

Mobile Office

Security and malware

Main article: Mobile virus

Symbian OS was subject to a variety of viruses, the best known of which is Cabir. Usually these send themselves from phone to phone by Bluetooth. So far, none have taken advantage of any flaws in Symbian OS – instead, they have all asked the user whether they would like to install the software, with somewhat prominent warnings that it can't be trusted.

However, with a view that the average mobile phone user shouldn't have to worry about security, Symbian OS 9.x adopted a UNIX-style capability model (permissions per process, not per object). Installed software is theoretically unable to do damaging things (such as costing the user money by sending network data) without being digitally signed – thus making it traceable. Commercial developers who can afford the cost can apply to have their software signed via the Symbian Signed program. Developers also have the option of self-signing their programs. However, the set of available features does not include access to Bluetooth, IrDA, GSM CellID, voice calls, GPS and few others. Some operators have opted to disable all certificates other than the Symbian Signed certificates.

Some other hostile programs are listed below, but all of them still require the input of the user to run.

  • Drever. A is a malicious SIS file trojan that attempts to disable the automatic startup from Simworks and Kaspersky Symbian Anti-Virus applications.
  • Locknut. B is a malicious SIS file trojan that pretends to be patch for Symbian S60 mobile phones. When installed, it drops a binary that will crash a critical system service component. This will prevent any application from being launched in the phone.
  • Mabir. A is basically Cabir with added MMS functionality. The two are written by the same author, and the code shares many similarities. It spreads using Bluetooth via the same routine as early variants of Cabir. As Mabir. A activates it will search for the first phone it finds, and starts sending copies of itself to that phone.
  • Fontal. A is an SIS file trojan that installs a corrupted file which causes the phone to fail at reboot. If the user tries to reboot the infected phone, it will be permanently stick on the reboot, and cannot be used without disinfection – that is, the use of the reformat key combination which causes the phone to lose all data. Being a trojan, Frontal cannot spread by itself – the most likely way for the user to get infected would be to acquire the file from untrusted sources, and then install it to the phone, inadvertently or otherwise.

Becoming open source

Template:Future software

Symbian 9.1 introduced capabilities and a Platform Security framework. To access certain APIs, developers have to sign their application with a digital signature. Basic capabilities are user-grantable and developers can self-sign them, while more advanced capabilities require certification and signing via the Symbian Signed program, which uses independent 'test houses' and phone manufacturers for approval. For example, file writing is a user-grantable capability while access to Multimedia Device Drivers require phone manufacturer approval. A TC TrustCenter ACS Publisher ID certificate is required by the developer for signing applications.

The Symbian Foundation was announced in June 2008 and came into existence in 2009. Its objective was to publish the source for the entire Symbian platform under the OSI and FSF approved Eclipse Public License (EPL). However, components within Symbian OS were licensed from third parties which prevented the foundation from publishing the full source under EPL immediately. Initially much of the source was published under a more restrictive Symbian Foundation License (SFL) and available to foundation member companies only.

Devices that used Symbian OS

On 16 November 2006, the 100 millionth smartphone running the OS was shipped.[20]

Developing on Symbian OS

The native language of Symbian is C++, although it is not a standard implementation. There were multiple platforms based upon Symbian OS that provided SDKs for application developers wishing to target Symbian OS devices – the main ones being UIQ and S60. Individual phone products, or families, often had SDKs or SDK extensions downloadable from the manufacturer's website too. With the various UI platforms unified in the Symbian platform a single there should be less diversity between manufacturer's SDKs from 2010 onwards.

The SDKs contain documentation, the header files and library files required to build Symbian OS software, and a Windows-based emulator ("WINS"). Up until Symbian OS version 8, the SDKs also included a version of the GCC compiler (a cross-compiler) required to build software to work on the device.

Symbian OS 9 and the Symbian platform use a new ABI and require a different compiler – a choice of compilers is available including a newer version of GCC (see external links below).

Unfortunately, Symbian C++ programming has a steep learning curve, as Symbian requires the use of special techniques such as descriptors and the cleanup stack. This can make even relatively simple programs harder to implement than in other environments. Moreover, it is questionable whether Symbian's techniques e.g. the memory management paradigm are actually so beneficial. It is possible that the techniques, developed for the much more restricted mobile hardware of the 1990s, simply cause unnecessary complexity in source code because programmers are required to concentrate on low-level routines instead of more application-specific features. It seems difficult, however, to make a move towards a more high-level and modern programming paradigm.[21]

Symbian C++ programming is commonly done with an IDE. For previous versions of Symbian OS, the commercial IDE CodeWarrior for Symbian OS was favoured. The CodeWarrior tools were replaced during 2006 by Carbide.c++, an Eclipse-based IDE developed by Nokia. Carbide.c++ is offered in four different versions: Express, Developer, Professional, and OEM, with increasing levels of capability. Fully featured software can be created and released with the Express edition, which is free. Features such as UI design, crash debugging etc. are available in the other, charged-for, editions. Microsoft Visual Studio 2003 and 2005 are also supported through the Carbide.vs plugin.

Symbian's flavour of C++ is very specialised.[citation needed]. However, Symbian devices can also be programmed using Python, Java ME, Flash Lite, Ruby, .NET, Web Runtime (WRT) Widgets and Standard C/C++. [22].

Visual Basic programmers can use NS Basic to develop apps for S60 3rd Edition and UIQ 3 devices.

In the past, Visual Basic, VB.NET, and C# development for Symbian were possible through AppForge Crossfire, a plugin for Microsoft Visual Studio. March 13, 2007 AppForge ceased operations, Oracle purchased the intellectual property, but announced that they do not plan to sell or provide support for former AppForge products. Net60, a .NET compact framework for Symbian, which is developed by redFIVElabs, is sold as a commercial product. With Net60, VB.NET and C# (and other) source code is compiled into an intermediate language (IL) which is executed within the Symbian OS using a just-in-time compiler.

There is also a version of a Borland IDE for Symbian OS. Symbian OS development is also possible on Linux and Mac OS X using tools and techniques developed by the community, partly enabled by Symbian releasing the source code for key tools. A plugin that allows development of Symbian OS applications in Apple's Xcode IDE for Mac OS X is available.[23]

Once developed, Symbian applications need to find a route to customers' mobile phones. They are packaged in SIS files which may be installed over-the-air, via PC connect, Bluetooth or on a memory card. An alternative is to partner with a phone manufacturer and have the software included on the phone itself. The SIS file route is more difficult for Symbian OS 9.x, because any application wishing to have any capabilities beyond the bare minimum must be signed via the Symbian Signed program. There are however various hacks, which allow installing unsigned programs with any capabilities to Symbian OS 9.x.

Introduction of the Symbian Signed system in which application developers need to pay in order to use some of the more attractive smartphone features (as contrasted to platforms like Palm OS and Windows Mobile) is making it an increasingly unpopular platform for Open Source projects[24], independent developers and small startups. This situation is worsened by the fragmentation of user interface systems (UIQ vs S60 vs MOAP)[25], meaning that developers need to build and maintain multiple incompatible versions of their software[26] if they want to target multiple devices which use the same underlying Symbian OS version.

Java ME applications for Symbian OS are developed using standard techniques and tools such as the Sun Java Wireless Toolkit (formerly the J2ME Wireless Toolkit). They are packaged as JAR (and possibly JAD) files. Both CLDC and CDC applications can be created with NetBeans. Other tools include SuperWaba, which can be used to build Symbian 7.0 and 7.0s programs using Java.

Nokia S60i phones can also run Python scripts when the interpreter Python for S60 is installed, with a custom made API that allows for Bluetooth support and such. There is also an interactive console to allow the user to write python scripts directly from the phone.

Hacking Symbian

S60 v3 and v5 (OS 9.x) devices can be hacked to remove the platform security introduced in OS 9.1 onwards thus allowing users to install "unsigned" files (files without certificates validated by Symbian) and allowing access to previously locked system files.[27] This allows changing of how the operating system works, allowing hidden applications etc. to be viewable and possibly increases the threat posed by mobile viruses as the operating system files are now exposed. [28].

See also

Notes and references

  1. ^ http://blog.symbian.org/2009/04/16/symbian-on-intels-atom/
  2. ^ http://www.symbian.org/media/news/pr2008_8.php
  3. ^ Apple Beats RIM, Microsoft To Become No. 2 Smartphone Provider
  4. ^ http://archive.salon.com/tech/view/2000/05/15/colly_myers/index.html
  5. ^ Symbian developer reports on porting from 8.x to 9.x
  6. ^ Solution to Nokia Slow SMS / Hang Problem
  7. ^ http://www.symbianos.org
  8. ^ http://developer.symbian.com/wiki/display/pub/Open+source+projects
  9. ^ http://s2putty.sourceforge.net/
  10. ^ Nokia - Nokia enriches application development with Qt for S60
  11. ^ Qt for S60 - Forum Nokia Wiki
  12. ^ Symbian - Nokia enriches application development with Qt for S60
  13. ^ All About Symbian - Nokia Announce Technology preview of Qt on S60
  14. ^ ars technica - Nokia releases first Qt preview for Symbian S60
  15. ^ Qt Labs Blogs - We’re porting Qt to S60!
  16. ^ Qt Software - Technology Preview - Qt for S60
  17. ^ Qt Software - How to get Qt running on your S60 phone
  18. ^ Symbian introduces POSIX libraries on Symbian OS
  19. ^ Symbian OS to gain POSIX libraries
  20. ^ Six Years of Symbian Produces 100 Models and 100 Million Shipments, The Smart PDA.
  21. ^ Symbian OS design faults
  22. ^ http://developer.symbian.org
  23. ^ Tom Sutcliffe and Jason Barrie Morley Xcode Symbian support
  24. ^ Why Symbian Signed must die
  25. ^ List of Symbian phones with platforms
  26. ^ List of SDKs for specific platforms
  27. ^ Nokia's S60 3rd Ed security has been HACKED? - Symbian Freak
  28. ^ S60 v3 Hacking - Mission accomplished, FP1 hacked!! - Symbian Freak

Bibliography

  • Morris, Ben (June 22, 2007), The Symbian OS architecture sourcebook : design and evolution of a mobile phone OS, John Wiley & Sons, p. 630, ISBN 0470018461
Retrieved from "https://en.wikipedia.org/w/index.php?title=Symbian_OS&oldid=312590884"