问题
I am developing an application which would redirect i/o from parallel port of, say, device A to the parallel port of device B. The two devices are connected on ethernet (LAN, WAN, internet, etc.).
Device A has a physical parallel port attached to it but device B is a machine with no parallel port on it. This is what makes me emulate a parallel port on device B such that windows thinks that it has a parallel port and works in the very manner with it as it works with parallel ports on hardware e.g. it auto detects when a device gets attached to the parallel port so that a driver for that device can be installed.
If any piece of hardware gets attached to the parallel port on device A the i/o is redirected to the parallel port on device B and the Windows on device B thinks that some hardware got attached to device B's own parallel port i.e. Windows doesn't know where in the world the hardware actually got attached; Windows just got fooled into thinking that the hardware is attached directly to device B.
My question is about the emulation part. How do I write a parallel port emulator in C++ for Windows 7 such that I fool Windows into thinking that it has a real/hardware parallel port?
A related question can be how does windows detect the hardware and on going changes in it e.g. when some hardware gets connected to the parallel port of a computer.
The program flow would be as follows.
- Read data from device A's parallel port.
- Write that data to device A's socket which sends it over to device B's socket.
- Read data from device B's socket.
- Write that data to device B's parallel port which makes windows think that some hardware got connected to it.
NB: I am to emulate a parallel port only i.e. parallel to parallel redirection only. No use of other ports on device B is allowed. That is a requirement for this application.
The part I've done so far is that I have written a program in C++ which reads and writes data from and to the parallel port respectively.
Please also let me know if you know of a better approach of parallel port to parallel port redirection over ethernet (LAN, WAN, internet, etc.).
回答1:
Stumbled upon this question in my own search for LPT virtualization on windows. I know this one is old and unfortunately I don't have an direct answer to the it either, but I thought I'll share what I've found so far that could help you getting started:
- Lakeview Research's Parallel Port Central
- Benryves.com, Remapped IO.DLL
- Downtown Doug Brown's Sivava Willem EPROM programmer on Windows 7 64-bit
来源：https://stackoverflow.com/questions/9082614/creating-a-virtual-parallel-for-windows-7-using-c