Hadar Vorenshtein & Meital Levy Instructor yavgeni Rivkin

PDAs have become popular now days because of the growing need for mobile devices and mobile computing. The problem: PDAs have limited resources. The solution: to form a network of devices. By creating a wireless network, resources can be shared (computing power and software availability)

Example 1: a PDA has to do a complex calculation. By dividing it to several parts and Transmitting It to other nearby devices we can balance The load and get better results (shorter time).

Example 2: Activate an application that we know of, but we are not present on our PDA (because of a small memory). And is present on other PDA that we can communicate with.

To form a WLAN network and use the DCOM features in Windows CE enviorment.

To form a connection between two COMPAQ IPAQs using INTEL WLAN adapter and WLAN Access Point ( protocol). To pass a calculation from one IPAQ to another over the network layer, using COM+ technology.

Learning about WLAN and the protocol. Establish a connection between Access Point (INTEL 2011) and a PDA (COMPAQ IPAQ) with a WLAN adapter (INTEL 2011). Learning the CE operating system, its features and its software development tools.

Learning how to develop an application in the CE environment. Learning the COM+ technology and practice it in Windows 2000 environment. Building a Compoment and a client in Windows Activate the component in INPROC mode.

Activate the component in LOCAL mode. Activate the component in REMOTE mode. Building a component and a client in Windows Ce. Activate the component in INPROC mode.

Other modes failed. The reason is: DCOM do not really supported by PocketPc2002. the call to CoCreateInstanceEx does not work although the MSDN claims it is.

Com+ provides services to application. It combines COM & DCOM and adds a several services. DCOM stands for Distributed COM which means that you can make COM communicate between different machines COM enables unrelated software objects to connect and interact.

COM+ Load balancing In-memory database Object pooling Queued components Event model Better administration DCOM Remoting architecture Distributed component services COM Interface-based programming Basic component facilities

Com+ enable the programmer to use it without dealing with the other layers.

SCM – in case of using COM the SCM is the process that locate and loads the requested component (In out of process activation) When you invoke a component in process you don’t need any intermediate

In case of using DCOM and remote components it marshals them and transfer parameters between them.

Client COM+ : SCM RPC UDP IP Ethernet Windows 2000 Object Client COM+ : SCM RPC UDP IP Ethernet Windows 2000 Object Windows 2000

Client COM+ : SCM RPC UDP IP WLAN Adapter Windows CE Object Client COM+ : SCM RPC UDP IP WLAN Adapter Windows CE Object AP Windows CE IPAQ

What we have created is a component and a client that use the COM+ to communicate between machines. The client calls the component and the COM+ provides the parameter passing and the enviorment for the remote process to run in.

Creating a component that performs a simple calculation and a client to use it. At first locally in process mode Locally in a separate process space. Configured it to remote activation on a different machine.

After we managed to do it in the Windows 2000 environment we moved to Windows CE

The Functions F CoInitializeEx - This function initializes the Component Object Model (COM) for use by the current thread. F CoCreateInstanceEx - The function creates an instance of a specific class on a specific machine (for DCOM). F CoCreateInstance – Same as CoCreateInstanceEx (different parameters and options) (for DCOM & COM).

F QueryInterface - Returns a pointer to a specified interface on an object to which a client currently holds an interface pointer. F CoUninitialize - Closes the COM library on the current thread, unloads all DLLs loaded by the thread, frees any other resources that the thread maintains, and forces all RPC connections on the thread to close.

COM+ is a very powerful tool. It was very interesting learning some of its abilities. COM+ and Windows CE is a developing area So it can be expected to encounter problems during development.

We got very close to target, it most likely that in the coming version of Windows CE.NET it can all be done. One conclusion is that you can never know until you try, even If the documentations tells cretin things.

Finally we want to thank : our Instructor Yavgeny And the LAB staff.