A Hole In My Head

Thanks ;)

what do you mean by multiplexing a physical serial port?  allowing multiple applications to open the same physical serial port, each application opening a different COM port number?  If so, this becomes very problematic because each application will want to configure the com port (stop bits, baud rate, read char timeout, etc) and each application will potentially have different settings  that will conflict with each other, making it impossible to share the physical COM port.  Or do you want to consume the data from the serial port in your driver and multiplex the data to the applications?

KMDF can be used to create a bus driver which will enumerate child devices.  Each child device can be a virtual serial port that you then use to fwd requests to the read serial port, but given w/out knowing how you plan to share the serial port, it is very hard to know of this is the correct solution.

d

you only need a bus driver if you want to dynamically create ports on the fly or you want to have the virtual ports be pnp chldren of the physical port (e.g. open device manager, view by connection and you see your ports as child devices of the real one).

Why do you think the first mode will ever work generically?  Or are you targeting a specific set of apps that will be aware of this sharing?

For the 2nd mode where everything is virtual, you do not need a bus driver.  rather you can install them as root enumerated devices, each port is its own device. your driver is the FDO for the device. what you do in the pure virtual mode is up to your driver.

d

can you change the apps?  otherwise what i suggest is that you read all the data from the real com port and then duplicate that data in each virtual com port.  this way one application cannot suck out the other's data...BUT, why would 2 applications consume the same barcode data at the same time?  that does not make much sense to me either...

d

yes, KMDF is the best choice to start with, but regardless of what you use to build the driver, there are a tremendous number of technical problems that you will have to solve.

good luck.

d