“Alex Cellarius” <acellarius@yahoo.com> wrote in message
news:1103_1037943811@192.168.0.5…
On 21 Nov 2002 19:22:24 GMT, David Gibbs <> dagibbs@qnx.com> > wrote:
Ricke <> rickard.bondesson@home.se> > wrote:
BlankTo be short, what I need is a bi-directional parallel port
driver.
I have checked the QNX home page and found that there doesn’t exist
such
a
driver.
On the other hand, it shows that people have been asking about it for
years.
Does anyone know of such a driver?
I suppose I probably could write one myself if I had to, but I thought
I
could try finding one here first.
I don’t know of one that has been written.
I’ve asked about this (internally) a couple times as well. The issue
seems to be that there is no one specification for how a bi-directional
parallel port should behave…but in essence there are different
protocols
used by different types of devices, and different types of parallel
hardware.
In essence, that one couldn’t write a “generic” bi-directional parallel
port
driver, but only a series of special-purpose bi-directional parallel
port
drivers.
I’ve seen this explanation before, but then how to explain that
DOS’s interlnk/intersvr and Norton Commander & Laplink’s
(and other, Xtlink, FM3 etc) ability to do this?
The point is that parallel interface is not intended to be used as network
adapter. If you take a look at IEEE 1284 you’ll find that all 5 possible
transfer modes expect one side of the communication link to be a host and
another a peripheral device. The host controls data flow in both directions.
It is not exactly suitable even for a simple pear to pear network. Following
this standard we’re going to end up with a set of drivers like
devc-epp-host.so, devc-epp-slave.so an so on.
All what you listed here are not standards or even protocols. They are
applications that adopted some algorithm of communication via parallel port.
Generally speaking, any algorithm of independent two way data transfer is a
hack of parallel interface. I’m not saying that it is bad. It is just the
way it is. The port itself is very attractive device to use it for a simple
network.
A basic link capability ala qtalk via the parallel cable
will be so useful in many instances where you don’t
have ethernet or serial, or need faster speed than
serial…
It is going to be another wheel just different diameter.
If QNX could take the lead, I think it will save many
a wheel being reinvented.
Maybe some day somebody invents something that will be taken as a standard
by everybody and adopted by IEEE committee. (If by this time we’ll be able
to see lpt not only in a museum 