Mobile Innovation

Design

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 flavor of C++[citation needed] very specialised. 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.

Competition

At its lowest level lie the base components of Symbian OS. This includes the kernel (EKA1 or EKA2 - see the 'History' section), and the user library which allows user-side programs to request things of the kernel. Symbian OS has a microkernel architecture, which means that the minimum necessary is within the kernel. It contains a scheduler and memory management, but no networking or filesystem support. These functions 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 character set conversion, a DBMS database, and resource file handling.

Further up, the software is not so readily arranged into a stack.

History

Psion
In 1980, Psion 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 1–3
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 PDA's and mobile phones.

EPOC Release 5 aka. Symbian OS 5
Psion Series 5mx, Series 7, Psion Revo, Psion Netbook, netPad, Ericsson MC218 were released in 1999 using ER5.

ER5u aka. Symbian OS 5.1
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. The 'u' in the name refers to the fact that it supported Unicode.

Symbian OS v6.0 and 6.1
Sometimes called ER6. The first 'open' Symbian OS phone, the Nokia 9210, was released in 2001.

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 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 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 offered advantages such as real-time response. 8.0b was deproductized in 2003.

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.

Symbian OS 9.0
This version was used for internal Symbian purposes only. It was deproductised 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 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. [2]

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 developers 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 based on Symbian OS 9.1, and should ship the P990 in Q3 2006. 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[3].

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). S60 3rd Edition Feature Pack 1 phones have Symbian OS 9.2.

Symbian OS 9.3
Released on 12th July 2006. Upgrades include native support for Wifi 802.11, HSDPA, Vietnamese language support.

Symbian OS 9.5
Announced in March 2007. Features up to 25% reduced RAM usage resulting in better battery life thanks to introduction of demand paging. Applications should launch up to 75% faster. Native support for mobile digital television broadcasts in DVB-H and ISDB-T formats and also location services. Additionally, SQL support is provided by SQLite.