Monday,
October 21, 2002
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Feature |
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Microsoft Windows CE
for mobile phones
Ashish Juneja
AS
the users worldwide relied more and more on computers for information,
the need to have "information anywhere and anytime" grew. With
the advancements in chip technology the miniaturisation paved way to
devices that provided on the move the features that were close to their
desktop counterparts.
From the PC that
brought the information revolution to the masses, the information is now
venturing into finding a new home even closer to the users -the mobile
devices. The user can choose from a plethora of devices that could vary
from pocket PCs to PDAs, tablets and smart phones but they all aim to
service the objective of "Information any time, anywhere and any
place."
With the shrinking
chip, Microsoft which gave the humble PC its first OS till it Windowed,
also shrunk its trademark Windows OS to fit in these devices and down
came the variant – Microsoft Windows CE which had a smaller footprint
but similar look and feel as the desktop counterpart.
The most popular mobile
gizmos hanging around are Mitsubishi’s Mondo SmartPhone which combines
a GSM mobile phone with a PDA, HP’s Jornada Series, Casio’s
Cassiopeia and Compaq’s iPaq — all running the Microsoft Windows CE
OS.
The RAM in a Windows-CE
system is divided into two areas — the object store, which is like a
permanent virtual RAM disk and the program memory, which is more like
the RAM in the conventional PC -used to store the heaps and stacks. The
OS and the pre-installed applications execute directly from the ROM and
the programs that are in the object store or flash-memory storage, are
first copied into the RAM and then executed. Windows CE supports a
variety of CPUs and system components.
To develop an
application for the Win CE, one needs Microsoft Embedded Visual Tools (EVT).
One can download it from the Microsoft’s Website. It also comes as a
part of the MSDN. The EVT requires a Windows CE SDK for a particular
device platform to be able to compile and download the application to
the platform. This SDK is created by the manufacturer of the device
using a Platform Builder and would usually be available from their
Website. The programming language used with the EVT will usually be
either VB or VC++.
The tool used by the
OEM to create the SDK for the device is called the Platform Builder (PB).
Many embedded devices in industries like automotive, industrial
automation, and telecommunications already use Windows CE based
applications. The user-interface need not necessarily be a GUI.
A Windows CE-based
solution answers mobile users needs for data access and integration
using the Microsoft SQL Server Windows CE Edition. With Windows CE SQL
server, users can take a piece of the company database with them and
access it using familiar tools. In many cases, SQL Server CE and a
mobile device can replace an application running on a laptop computer.
People on the move, do not usually need information on the entire
database, just a part of it.
The combination of
Embedded Visual Tools and SQL Server CE lets the programmers reuse
existing code from VB/VC++ applications in mobile clients.
Another great advantage
with SQL Server CE is the ease with which you can keep the data
synchroniSed with the main server running the SQL Server 2000 database.
There are two ways of
doing it –Merge Replication and Remote Data Access (RDA). Merge
replication manages changes to the data when subscribers either are
disconnected from the network or operate independently of each other and
the publisher. The replication is supported through both wired and
wireless LAN/WAN connectivity. The replication uses Microsoft IIS as the
conduit to a SQL 2000 server.
In the alternative
Remote Data Access, the client initiates and controls the flow of data
instead of depending on a publisher to coordinate updates. RDA can work
with older version of SQL Server as well, while Merge Replication
requires SQL Server 2000.
Whether you choose
merge replication or RGA depends mainly on how the users use the data on
the Windows CE device. Merge replication is well suited to environments
where multiple persons through
multiple applications can update tables. If the data on the server
mostly supports a Windows CE application that operated independently of
other users, RDA is probably the better choice.
All said and done, the
bottom line remains the bandwidth. Just like the last mile is relevant
for the land line connectivity, unless the wireless connectivity
technology improves, the devices on the move will be of little
relevance.
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