Symbian OS
Symbian OS is an
operating system, designed for mobile devices, with associated
libraries,
user interface frameworks and reference implementations of common tools, produced by
Symbian Ltd. It is a descendant of
Psion's
EPOC and runs exclusively on
ARM processors.
Symbian is currently owned by
Ericsson,
Panasonic,
Siemens AG,
Nokia, and
Sony Ericsson. Whilst
BenQ has acquired the mobile phone subsidiary of
Siemens AG the Siemens AG stake in Symbian does not automatically pass to BenQ - this will need the approval of the Symbian Supervisory Board.
There are a number of
smartphone user interface platforms based on Symbian OS, including open platforms
UIQ,
Nokia's
Series 60,
Series 80 and
Series 90 and closed platforms such as that developed for
NTT DoCoMo's
FOMA handsets. This adaptability allows Symbian OS to be used on smartphones with a variety of form factors (e.g. clam-shell or "monoblock"/"candybar", keypad- or pen-driven).
Symbian OS, with its roots in
Psion Software's
EPOC is structured like many desktop operating systems, with
pre-emptive multitasking,
multithreading, and
memory protection.
Symbian OS's major advantage is the fact that it was built for handheld devices, with limited resources, that may be running for months or years. There is a strong emphasis on conserving memory, using Symbian-specific programming idioms such as
descriptors and a
cleanup stack. Together with other techniques, these keep memory usage low and
memory leaks rare. There are similar techniques for conserving disk space (though the disks on Symbian devices are usually
flash memory). Furthermore, all Symbian OS programming is event-based, and the
CPU is switched off when applications are not directly dealing with an event. This is achieved through a programming idiom called
active objects. Correct use of these techniques helps ensure longer battery life.
All of this makes Symbian OS's flavour of
C++ very specialised, with a steep learning curve. However, many Symbian OS devices can also be programmed in
OPL,
Python,
Visual Basic,
Simkin, and
Perl - together with the
Java ME and
PersonalJava flavours of
Java.
Symbian OS competes with other mobile operating systems, such as
Windows Mobile,
Palm OS, and
Linux. It also competes with the embedded operating systems used on lower-end phones, such as
NOS and
OSE, which tend to be maintained by the phone companies themselves. Symbian OS' major advantage over these embedded operating systems is its modularity - there is runtime linking between dynamically linked shared libraries (DLLs, see
dynamic linking) on the device, and an emphasis on plug-in architectures. This makes complex phones quicker to develop, though this is sometimes offset by the complexity of Symbian OS C++ and the awkwardness of going to another company for an OS (instead of doing it in-house).
The advantages over other 'open' OS competitors (such as
Linux and
Windows Mobile, the latter is not
Open Source) are more debatable. Phone vendors and network operators like the customisability of Symbian OS relative to Windows. This customisability, though, makes integrating a Symbian OS phone more difficult. It's possible that Linux goes too far in the other direction, and is simply too hard to make a phone from at the moment. Symbian OS's ground-up design for mobile devices should make it more power- and memory-efficient, as well as being flexible.
At its lowest level sit the
base components of Symbian OS. This includes the
kernel (
EKA1 or
EKA2 - see the 'History' section), along with the user library which allows user-side applications to request things of the kernel. Symbian OS has a
microkernel architecture, which means that the minimum necessary is within the kernel. It does contain a
scheduler and
memory management, but no networking or filesystem support. These things are provided by user-side servers. The base layer includes the file server, which provides a fairly
DOS-like view of the filesystems on the device (each drive has a drive letter, and backslashes are used as the directory delimiter). Symbian OS supports various filesystem types including
FAT32 and Symbian OS-specific NOR flash filing systems. The filesystem is generally not exposed to the user through the phone user interface.
Immediately above base are a selection of
system libraries. These take all shapes and sizes, including for example character set conversion, a DBMS database, and resource file handling.
Further up, the software is not so readily arranged into a stack.
There is a large
networking and communication subsystem, which has three main servers - 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, implementing different types of networking protocol scheme. There's lots of stuff relating to short-range communication links too, such as
Bluetooth,
IrDA and
USB.
There's also a large amount of
user interface code. Even though the user interfaces themselves are maintained by other parties, the base classes and substructure ("UIKON") for all UIs are present in Symbian OS, along with certain related servers (for example, a view server which controls transitions between different phone user interface screens). There's a lot of related
graphics code too - such as a window server and a font and bitmap server.
An
application architecture provides for standard application types, embedding, and file and data recognition. There is also a selection of
application engines for popular smartphone applications such as calendars, address books, and task lists. A typical Symbian OS application is split up into an engine DLL and a graphical application - the application being a thin wrapper over the engine DLL. Symbian OS provides some of these engine DLLs.
There are, of course, many other things that don't yet fit into this model - for example,
SyncML,
Java ME providing another set of APIs on top of most of the OS and
multimedia. Quite a few of these things 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 means that phone vendors need to do a great deal of integration work to make a Symbian OS phone.
Symbian OS device manufacturers also get supplied with an example user interface layer called
TechView. This looks very similar to the user interface from a
Psion Series 5 personal organiser, so isn't particularly similar to any given phone user interface, but provides a basis to start customisation. It is also the environment in which a lot of Symbian OS test code and example code runs.
In 1980,
Psion Software was founded by David Potter.
EPOC16. Psion released several
Series 3 devices from 1991 to 1998 which used the EPOC16 OS, also known as
SIBO.
EPOC OS Releases 1â€"3. The
Series 5 device, released in 1997, used the first iterations of the EPOC32 OS.
EPOC Release 4. Oregon
Osaris and Geofox 1 were released using ER4.
In 1998,
Symbian Ltd. was formed as a partnership between Ericsson, Nokia, Motorola and Psion, to explore the convergence between PDAs and mobile phones.
EPOC Release 5 a.k.a.
Symbian OS v5.
Psion Series 5mx,
Series 7,
Psion Revo,
Psion Netbook, netPad, Ericsson MC218, and the Ericsson R380 were released in 1999 using ER5.
ER5u a.k.a.
Symbian OS v5.1. u = Unicode. The first phone, the Ericsson R380 was released using ER5u in 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.
Symbian OS v6.0 and
v6.1. Sometimes called ER6. The first 'open' Symbian OS phone, the Nokia 9210, was released on 6.0.
Symbian OS v7.0 and
v7.0s. 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 6600, 7310) as well as several FOMA phones in Japan.
In 2004, Psion sold its stake in Symbian.
Also in
2004, 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 v8.0. 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 SymbianOS v8.1b. 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, whilst EKA2 offered advantages such as a hard real-time capability.
Symbian OS v8.1. 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 realtime support but not allowing open application installation.
Symbian OS v9.0. This version was used for internal Symbian purposes only. It was deproductised in 2004.
Symbian OS has generally maintained reasonable
binary 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.
[Symbian developer reports on porting from 8.x to 9.x]Symbian OS v9.1 released early 2005. Improvements in the OS mean that applications and content, and therefore a developers investment, are better protected than ever. The new ARM
EABI binary model means developers need to retool and the security changes mean they may have to recode.
S60 3rd Edition phones have Symbian OS 9.1. Sony Ericsson is shipping the M600i based on Symbian OS 9.1 and should ship the P990 in Q3 2006.
Symbian OS v9.2 released Q1 2006. Support for
Bluetooth 2.0 (was 1.2) and
OMA Device Management 1.2 (was 1.1.2).
S60 3rd Edition Feature Pack 1 phones have Symbian OS 9.2.
Symbian OS v9.3 released on 12 July 2006. Upgrades include native support for Wifi
802.11,
HSDPA, Vietnemese language support.
The following
Open Source software has been rewritten for Symbian 9.1:
*Utilities:
PuTTYInternet Radio*Game emulation:
ScummVM (Currently only a very early port is available)
Symbian OS has been 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, of course, the average mobile phone user shouldn't have to worry about such things, so Symbian OS 9 is adopting a
capability model. Installed software will theoretically be unable to do damaging things (such as costing the user money by sending network data) without being digitally signed - thus making it traceable. Developers can apply to have their software signed via the
Symbian Signed program. Developers also have the option of self-signing their programs.
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 Series 60 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.
* Frontal.A is a 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 stuck on the reboot, and cannot be used without disinfectation - that is, the use of the reformat key combination which causes the phone to lose all data. Being a trojan, Frontal.A 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.
A common question is whether Symbian OS is "open". It is not open in the sense of
Open Source software - the source code is not publicly available. However, nearly all the source code is provided to Symbian OS phone manufacturers and many other partners. Moreover, the APIs are publicly documented and anyone can develop software for Symbian OS. This contrasts with traditional embedded phone operating systems, which typically cannot accept any aftermarket software except Java applications.
Symbian is also open in terms of the
Open Standards it supports.
*
Ericsson R380 (2000) was the first commercially available phone based on Symbian OS. As with the modern "FOMA" phones, this device was closed, and the user could not install new C++ applications. Unlike those, however, the R380 could not even run Java applications, and for this reason, some have questioned whether it can properly be termed a 'smartphone'.
*
Nokia 9210 Communicator
smartphone (32-bit 66 MHz
ARM9-based
RISC CPU) (2001),
9300 Communicator (2004),
9500 Communicator (2004) using the
Nokia Series 80 interface
*
UIQ interface:
** Used for PDAs such as
Sony Ericsson P800 (2002),
P900 (2003),
P910 (2004),
P990,
W950,
M600, Motorola A920,
A925, A1000, DoCoMo M1000, BenQ P30, P31 and
Nokia 6708 using this interface.
*
Nokia Series 60 (2002)
** Nokia Series 60 is used in various phones, the first being the
Nokia 7650, then the
Nokia 3650, followed by the
Nokia 3620/3660,
Nokia 6600,
Nokia 7610,
Nokia 6670 and
Nokia 3230. The
Nokia N-Gage and
Nokia N-Gage QD gaming/smartphone combos are also Series 60 platform devices. It was also used on other manufacturers' phones such as the
Siemens SX1,
Sendo X,
Panasonic X700,
Panasonic X800,
Samsung SGH-D730, SGH-D720 and the
Samsung SGH-Z600. Recent, more advanced devices using Series 60 include the
Nokia 6620,
Nokia 6630, the
Nokia 6680 and
Nokia 6682, a next generation N series, including the
Nokia N70,
Nokia N80,
Nokia N90, and
Nokia N91, and the enterprise (ie business) model E series, including the
Nokia E60,
Nokia E61, and
Nokia E70. For an up to date list, refer to the Symbian Series 60 website.
[Symbian series 60 phones]*
Nokia 7710 (2004) using the
Nokia Series 90 interface.
*
Fujitsu,
Mitsubishi,
Sony Ericsson and
Sharp phones for NTT
DoCoMo in Japan, using an interface developed specifically for DoCoMo's
FOMA "Freedom of Mobile Access" network brand. This UI platform is called MOAP "Mobile Orientated Applications Platform" and is based on the UI from earlier Fujitsu FOMA models.
There are multiple platforms, based upon Symbian OS, that provide an
SDK for application developers wishing to target a Symbian OS device - the main ones being UIQ, Series 60, etc. Individual phone products, or families, often have SDKs or SDK extensions downloadable from the manufacturer's website too. 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 uses a new
ABI and so requires a new compiler - a choice of compilers is available including a new version of GCC (see external links below). In terms of SDKs, UIQ Technology now provides a simplified framework so that the single UIQ SDK forms the basis for developing on all
UIQ 3 devices, such as the
Sony Ericsson P990 and
Sony Ericsson M600.
Symbian C++ programming is commonly done with a commercial
IDE. Previously,
Visual Studio was common, but for current versions of Symbian OS, a Symbian-specific version of
CodeWarrior is favoured. The CodeWarrior tools will be replaced during 2006 by
Carbide.c++, an
Eclipse-based IDE developed by Nokia. It is expected that Carbide.c++ will be offered in different versions: a free version may allow users to prototype software on the emulator for the first time in a free product.
Visual Basic, VB.NET, and C# development for Symbian can be accomplished through
AppForge Crossfire, a plugin for Microsoft Visual Studio.
There's 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.
[Tom Sutcliffe and Jason Barrie Morley Xcode Symbian support]Once developed, Symbian OS 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 or in some cases via Bluetooth or memory cards. An alternative is to partner with a phone manufacturer to have the software included on the phone itself. The SIS file route will be a little more difficult from Symbian OS 9, because any application wishing to have any capabilities beyond the bare minimum must be signed via the Symbian Signed
[Symbian Signed] program.
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.
*
Smartphone*
Smartmovie - A Symbian App to Watch DIVX\Xvid on your Phone
*
Operating System Embedded (OSE)
*
Multiplayer Mobile games*
Nokia OS (NOS)
*
S60 Platform*
History of OPL*
History of Symbian, 1980-2004* Symbian official sites
**
Symbian Company Website including
release history**
Symbian Signed, an application signing and verification process
*
DMOZ directory of Symbian software*
DMOZ directory of Symbian sites**
All About Symbian News and information site for Symbian OS powered phones with active forum
**
SymbianOne.com An active Community portal for mobile developers, device makers, and carriers interested in symbian devices
**
My-Symbian Symbian OS Communicators and Smartphones Info Center, with active discussion forum
**
Symbian OS OpenSource Community Center, This site is dedicated to the development of Open Source programs for SymbianOS.
*
Talk about Symbian SmartphonesTalk.com
*
AppForge AppForge provides a plugin to Visual Studio .NET to enable VB.NET and C# development for Symbian.
*
Symbian Example A collection of compilable code examples for the Symbian OS
*
Symbian OS Unit An open-source unit testing framework for Symbian OS devleopment.
*
NewLC A Symbian C++ developer portal with news, forums, tutorials and more
*
Symbware Directory of freeware and open source software for Symbian OS.
*
Symbian Freak Website for smartphone users, with a smart phone discussion forum
*
Symbian Watch Symbian blog.
*
Symbian Wiki*
Carbide.c++ is an Eclipse-based IDE for Symbian C++ development, developed by Nokia. Available in 2006
