It might have been the tiny keyboard, the click wheel, and the ability to check email on the train that made the CrackBerry so addictive to business users, but it's the software that's kept enterprise IT departments hooked for so long.

Two separate, but inextricably linked pieces of software have been key to Research In Motion's (RIM) success: its BlackBerry OS, which runs the phones, and its BlackBerry Enterprise Server (BES), which gives IT departments the ability to manage those devices--and more importantly, in the early days, provided the first push email on a mobile phone.

Since its position of dominance in the mid-2000s, RIM has had to rethink both BlackBerry OS and BES to take into account a new world of touchscreens and the growth of the bring-your-own-device (BYOD) trend, both of which undermined its once impregnable position in the enterprise.

BlackBerry OS and BES: The early days

The first version of BlackBerry OS debuted on the RIM 850 Wireless Handheld, a pager that had no phone functionality, but which could send email and messages from its six or eight-lined screen, thanks to its QWERTY keyboard.

This rather basic x86-based version of the BlackBerry OS (version 1.0) was developed in-house by RIM and made its debut in January 1999. As the device was a pager only, the software didn't need to perform many functions, and dealt primarily with messaging and emails. However, to support it, RIM introduced its BlackBerry wireless email product, BlackBerry Enterprise Server for Microsoft Exchange.

The beta and early versions of BES were pretty basic. It could forward email to the mobile device, but would only work with Exchange Server 5.5. However, it was the introduction of BES that would underpin the majority of RIM's success in the years that followed.

BES left beta and went on general release in June 1999; it would be nearly another year before version 2.0 came along, adding support for IT policies. Microsoft's DirectPush email (which connected with Exchange accounts) would wait until the release of Windows Mobile 5 in 2005 before it added push email, let alone a feature set comparable to RIM's subsequent BES offerings.

In April 2000, RIM announced its 957 Wireless Handheld, which brought along with it BlackBerry OS 2.0. The device included wireless email, internet, paging, and an organiser. RIM announced a development environment for Java the same year.

The 5810: Java, apps, and OS 3.x

By 2002, RIM was ready to launch the 5810, the first of its phones to be Java-based. It used the Java 2 Micro Edition (J2ME) platform in addition to its own proprietary APIs and C++ to create BlackBerry OS 3.x (in the case of the 5810, version 3.6).

Although the 5810 only allowed phone calls through a headset, it was the first to include a GSM/GPRS radio. It provided wireless email, internet, paging, and organiser features, like its predecessor. More importantly, it was the first time third-party developers could realistically start thinking about building apps for BlackBerry devices, opening the door to businesses that wanted or needed to build bespoke apps for deployment in a secure environment.

BlackBerry OS 3.x was released on 4 March, 2002. By September, the release of BES 3.5 had added support for over-the-air calendar sync and Exchange 2000. RIM also added key features, such as the Mobile Data Service (which allowed access beyond email to corporate documents) and the BlackBerry Web Client (which laid the groundwork for BlackBerry Internet Service, or BIS). Although BIS didn't provide the "push" email convenience of the BES service, it allowed customers to access personal and business email accounts from a web-based interface.

2003: A big year

2003 was a big year for RIM's software: while its core BlackBerry platform didn't get a significant overhaul, it did receive support for over-the-air app deployment and new APIs, further opening the door to developers.

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BlackBerry OS Version 4.0 was also the first time that a core build of the software would be iteratively updated over a number of years before a successor would be introduced. In total, it was another five years before BlackBerry OS 5.0 arrived.

It also brought a raft of new features to devices and the BES server to widen the company's appeal to the government agencies and other businesses that insisted on encrypted, secure communications--with security still the key draw of RIM's BlackBerry devices and services.

Chief among the new features was the introduction of BlackBerry Connect, a way of allowing other handset makers to connect customers to their secure BES server for push email.

It also added S/MIME (Secure/Multipurpose Internet Mail Extension) to corporate and government customers for added security: another hallmark that led RIM to dominate the business market.

BES 4.0

In 2004, RIM announced BES Server 4.0 for Microsoft Exchange 2003 and IBM Lotus Domino. BES 4.0 and its predecessors also introduced numerous other new features and updates along the way, including support for Windows Server 2003 and Outlook 2003. Version 4 also brought PIM (personal information management) syncing of contacts, tasks, and memos.

RIM's first real attempt to tap into the elusive consumer buyers was the Pearl 8100.

Rivals such as Windows Mobile SE2003 (also released in 2004) could not really challenge RIM's package of features, although the next edition would bring them closer to parity. However, it did bring support for new display resolutions and supported access to networks using WPA. The most notable features of Windows Mobile 2005 included support for push email, Bluetooth support, and the introduction of Microsoft Office Mobile.

A batch of updates to BlackBerry OS between 2005 (OS 4.1) and 2008 (OS 4.7) increased the stability of the platform and introduced new functionality to take account of the new colour displays on handsets and RIM's desire to appeal to the consumer, as well as the business crowd.

At the end of 2005, RIM made around $132 million in software revenues and claimed 4.2 million active users, making it easily one of the largest mobile enterprise software vendors of the time. Its first real attempt to tap into the elusive consumer buyers was the Pearl 8100, which went on to become one of its best-selling phones of all time and was the first BlackBerry to include a camera and media player applications.

However, with the release of the iPhone in 2007 and the growing popularity of touchscreen displays, RIM needed its next milestone update to stem the turning tide. Unfortunately, it proved insufficient in the long run.

Enter BlackBerry OS 5.0

By the time BlackBerry OS 5.0 came along on the Bold 9000 (and subsequent models) in 2008/2009, the platform had expanded to include many new features, including mail folder management options, remote file access to shared Windows folders, an application switcher shortcut, and memory management options, as well as significant improvements to BlackBerry Maps, multimedia, and security. It also got a boot screen.

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Despite having a powerful feature set, the operating system was complicated in comparison to the new iOS and Android platforms gaining in popularity, and not even RIM's full touchscreen Storm device could provide any kind of challenge following disappointing software and hardware performance.

"The story is complex. In retrospect, what became a key miscalculation for RIM in the enterprise was not recognising soon enough that the enterprise business was becoming increasingly an after-effect of the consumer business," Roberta Cozza, research director of consumer devices at Gartner, told ZDNet.

Thankfully, much of that core business--the enterprise market--was still keen on the security afforded by BES. Many of the new features in OS 5.0, such as the network file explorer, required BES 5.0 to work.

Since BES 5.0 was introduced in 2009, it has received iterative updates and the base version is still in use today. However, with the introduction of BlackBerry 10 devices at the end of January, BES customers will need an upgrade to BES 10 in order to manage the new devices. (If you want to know how you'll manage your new handsets, you can check out " BlackBerry 10 devices are almost here--but how will you manage them?"

BlackBerry OS 6 and 7

Later members of the BlackBerry Bold family, such as the 9700, the Curve 9300, and the Torch, used the BlackBerry 6 operating system.

The new OS included...

...an overhaul of the graphics, icons, home screen, and other UI elements and features, such as a WebKit tabbed browser for faster and more stable browsing. It also brought multi-touch support to the platform for actions like zooming.

"The lines between a business and consumer user have gone, and a company that wants to succeed within enterprise also needs to win consumers today,"--Roberta Cozza, Gartner.

BlackBerry OS 6 also baked social options into the platform for the first time (although apps were available on previous versions), and brought a universal search box for finding that specific email, message, song, person, or video you were looking for.Despite the features, neither the software nor hardware was enough to draw the spotlight back onto RIM.

"The lines between a business and consumer user have gone, and a company that wants to succeed within enterprise also needs to win consumers today. Not envisioning and not reacting fast to key consumer market shifts toward ecosystem/applications, touch designs, personal cloud, all contributed to favour the faster-paced competition, and produce for RIM this downward spiral where both consumer and enterprise segments are closely interrelated," Cozza said.

Nevertheless, while RIM might have been floundering and slow to respond to the new generation of touchscreen handsets, it was at least doing better than its rival Palm, which, despite having a strong software platform, was eventually bought by HP.

The current generation of BlackBerry handsets--such as the Bold 9900 and Torch 9850/9860--use the BlackBerry 7/7.1 OS released in 2011. It brought upgrades such as BlackBerry Messenger (BBM) 6, HTML5 video support, BlackBerry ID integration, faster browsing, better graphics, and voice-activated universal search.

Here comes BlackBerry 10

The new operating system includes a drastic overhaul of the UI , a dual-layered virtual keyboard that learns exactly where you hit each key and predicts which one you were intending to press, a new home screen with tiles, and hundreds of other changed or new features. Hands on-testing with a pre-beta build of the software quickly showed it to be more intuitive and user-friendly than previous, or current, generations of the BlackBerry OS.

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RIM has aligned its software elements, BlackBerry 10, BlackBerry Enterprise Service 10 (BES 10), Balance, and Mobile Fusion (albeit, without the name anymore) around this launch. It will need to resist future fragmentation of these platforms to ensure it has a good grounding to compete against the current leaders in the mobile market, iOS and Android. Like it or not, BlackBerry 10 is the foreseeable future for RIM smartphones and tablets.

Unlike its predecessors, it is based on a completely different Unix-like core OS called QNX. QNX was also used on RIM's only tablet, the PlayBook, the first version of which was introduced in 2011. The new OS was briefly called BBX, until RIM was promptly sued and changed the name to BlackBerry 10.

Although no handsets running the new OS are currently available, RIM has shown off the features on numerous occasions. On January 30, the first handsets will be officially announced and are expected to include touchscreen models and QWERTY-equipped handsets.