Re: [PARPORT] Parallel sniffing idea..


grant@torque.net
Tue, 9 Mar 1999 12:22:51 -0500 (EST)


> I've had this idea for quite a while, and I was planning on implementing
> it before going public, but I just don't have the time.
>
> My idea is this: Get a machine with 2 bi-directional parallel ports. On
> lp0, attach a null-printer cable to another machine running Win9x with
> drivers for the parallel device. Then on lp1 of the first maschine, attach
> the device. Write software that would send all information from lp0 to
> lp1, but log it to a file-- that way, it would be very easy to determine
> the information being send to the device, thus making it much easier to
> write drivers.
>
> Sound interesting?

It is an interesting idea - you'd have to cross the control and status
bits over in the cable to the Windows machine, though. Fortunately,
there's five of each ;-)

You'll also have to be careful with the sequence in which you move
the data between the ports, so you don't create any glitches. The biggest
problem will be knowing whether the Windows PC is reading or writing
the data bits - since the direction is not actually present on the cable.
(And you could well burn out the ports if they are driving against each
other.)

Meanwhile, ...

Has anyone investigated http://www.sysinternals.com/portmon.htm ??

I doubt if the windows version would help us, but I think the NT
version might actually be useful - assuming that NT does not allow
drivers to bypass the HAL and talk directly to a parallel port.

(I plan to try it out as soon as I can find some time, but I'm resisting
installing NT ;-) ).

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Grant R. Guenther grant@torque.net
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