By Alejandro Panizza, from ARTech's development team
There are many terms that may be used to refer to pocket devices: Handhelds, Pocket PC's, PDA's, (Personal Digital Assistant), etc. Today, PDA's born with the feature of small personal planners have become real pocket PC's that include Office applications, Internet browsers, as well as multimedia functions, audio, video, and the possibility of connecting to local networks and Internet.
Based on the latest models that we know, the market in the coming years is expected to diversify and expand: There are models for personal use at low cost and also models that are clearly targeting the business market, and all of them include a variety of standard options that range from connections for wireless networks ( WiFi*, and Bluetooth* ), to digital fingerprint scanners for protecting access to information.
In spite of this diversification, the main market for PDA applications continues to be the segment of vertical applications developed in a customized way. These systems are usually developed as a complement to the company systems, and provide both the mobile integration of data inside and outside the company, and the possibility of having information available on-line (or inside the pocket) anywhere, anytime, as a source of added value.
What type of applications may be made?
The applications enabled by this new platform are similar, component-wise, to any desk application (graphic interface, database access, etc). However, they differ from this type of application from the moment that they function in a different device, which means that they have other types of limitations as well as other possibilities for incorporating new features.
Some aspects to bear in mind when planning mobile solutions or when using mobile components in planning:
* Scope
Although current devices have a larger memory than desk PC's had a few years ago, their processing and storage capacity is limited. This is why it is important to define the set of relevant subsystems, and for each application, to define the subset of data that are useful or necessary in the PDA from such application.
* Data integration and synchronization.
It is obviously not always possible to develop a corporate application foreseeing the eventual need to incorporate a part of it in a mobile environment; this means that in practice, mobile applications must many times live with preexisting applications to which they are integrated by using different mechanisms.
Additionally, it is common for each PDA client to use a different data subset (for example sales representatives who load the data corresponding to their work zones into their PDA's, etc), which also needs an updating process.
Replication (data synchronization) is the most common integration mechanism, and can be carried out by replicating files through proprietary solutions or by replicating a part of the database. The mechanisms provided by the Windows platform for replication (ActiveSync) can also be used by working with functions from the operative system. The synchronization task is therefore used for integrating information that is locally used within the device, into the corporate system.
There are other means for integrating applications such as connecting these devices to local networks or Internet, or connecting them asynchronically by using remote calls. An example of this is using RPC or Webservices for handling centralized information.
* Interface.
When designing pocket applications, it is especially important to plan what type of services will be provided based on the possibilities offered by a given device. This should be kept in mind for carefully designing the interface and it is all a consequence of the reduced size of the screen and the limitations for entering data.
The Pocket PC and the GeneXus generator for this platform
The PocketPC 2002 platform is the latest version from Microsoft's operative system for these devices. Its first comparative advantage lies in the level of familiarity that the application users have with the Windows interface, which makes user training easier. Secondly, there is the compatibility between applications (PocketWord, PocketExcel, PocketOutlook) and data files (Ado CE y SQL Server CE ) and Windows desktop equipment, which makes application integration easier.
The GeneXus Olimar version includes an option for generating winform applications for PocketPC environments by using the Embedded Visual Basic language. The EVB generator enables GeneXus programmers to make relatively complex applications in a PocketPC device, just like GeneXus enables them to do so in other environments. For using this generator, it is necessary to have the EVB 3.0 language as well as emulators from the PocketPC Platform, both available for free at http://www.microsoft.com.
Nowadays, the GeneXus generator for PocketPC is in the betatest process of the GeneXus Olimar version. There are users from the GeneXus community who have already embarked on development projects with this new generator.
More information:
ARTech's GeneXus Olimar version
http://www.gxtechnical.com/olimar
Pocket PC
http://www.microsoft.com/mobile/pocketpc
* WiFi and Bluetooth are two standards for short-distance, wireless networks.