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From: veit@mururoa.gmd.de (Holger Veit)
Subject: Re: Epson LQ printer - Can it be done?
Message-ID: <1993Sep16.115459.24351@gmd.de>
Sender: veit@mururoa (Holger Veit)
Nntp-Posting-Host: mururoa
Organization: GMD - German National Research Center for Computer Science
References: <TONY.93Sep9182513@marge.apana.org.au> <1993Sep11.124630.22284@gmd.de> <279b1mINNjgb@bonnie.tcd-dresden.de>
Date: Thu, 16 Sep 1993 11:54:59 GMT
Lines: 80
In article <279b1mINNjgb@bonnie.tcd-dresden.de>, j@bonnie.tcd-dresden.de (J Wunsch) writes:
|> veit@mururoa.gmd.de (Holger Veit) writes:
|>
|> >... My recommendation is to verify that your
|> >printer cable has *all* line connected.
|> [...]
|> >Get a correct Centronics cable, and try again.
|>
|> Holger, it's already the Nth posting of that kind from you.
|>
|> Please accept that this IS A BUG in *BSD, not in the cables. The bug has
If so, please explain me the following things:
1. My problem went away *entirely* with both interrupt- and interruptless
driver on my system, after I changed cables. This worked with pk-0.2,
and pk-0.2.3/4 didn't change a bit here.
There is no misdetection, no hanging and no crash, and this is with a
plain 20$ multi-I/O card.
2. If this is a bug, and everyone agrees that it is, why the hell hasn't
someone digged into that and tried to correct this? According to
the number of questions about the printer interface (most of them
"how can I generate a..." rather than "why does my ... crash?")
this should be an important area for fixing. But obviously it is
more fun to change db formats, a.out formats to make everything
different than to fix essential things. I see no need in this, because
I do not know how to fix a bug I cannot see.
3. If this worked with pre-0.2.3 lp drivers, is it really so difficult to
compare the working version with the apparently buggy "innovation", and
analyze the effect? Apparently some changed code caused this, and if
it is not the lp driver, possibly another side effect has been built in.
According to "Bill's assertion"(TM) (that most of the patches are wrong
or bad), this might well be, and it is important to identify this bug then.
I think the (mostly correct) improvement of interrupt handling by bde
caused this (and thus triggered misbehavior of some hardware), but then
the old code shouldn't work any longer...
4. I don't know about your printer, but sometimes it appears to be a
flaky or non standard hardware interface of the printer than
really a software bug in *BSD (Don't tell me it works fine with DOS).
So I have to extend my previous posting: Your cable may be bad,
your printer card may be faulty or your printer does a non-standard
protocol (or has internal interface lines open or connected incorrectly).
Seeing the software working here, and not working there, it must be
a difference in hardware (though of course, the reason may be that
the *BSD driver does not access the interface correctly for all existing
cases. At least I doubt, Epson or HP build printers with bad interfaces).
So, did you exchange cables, printer, printer port, tried on *different*
systems?
|> printer port. Yes, indeed, some{thing,one} is writing some byte to the
|> printer port - it ain't the lp driver, though!
So then, rename the /dev/lp to something like /dev/myprinter
(so normal apps should no longer find a printer where they can send
bytes to), kill the lpd and print via cat >/dev/myprinter. If you still
get problems, your hardware is probably bad. About the theory of sending
bytes by some{thing,one}: I have a LJ4L with a powerdown mode which wakes
it up when some byte is sent to the printer. I never encountered any
wakeups unless I explicitly sent data to it.
|>
|> I can reselect the printer (via an ioctl), then it'll work again for
|> some time. But often it's getting deselected during it next print job:-((
|>
|> I have no idea where to look for this...
Should be enough stuff to check in this letter.
|> --
|> in real life: J"org Wunsch | ) o o | primary: joerg_wunsch@tcd-dresden.de
|> above 1.8 MHz: DL 8 DTL | ) | | private: joerg_wunsch@uriah.sax.de
|> | . * ) == |
|> ``An elephant is a mouse with an operating system.''
--
Dr. Holger Veit | INTERNET: Holger.Veit@gmd.de
| | / GMD-SET German National Research | Phone: (+49) 2241 14 2448
|__| / Center for Computer Science | Fax: (+49) 2241 14 2342
| | / P.O. Box 13 16 | Had a nightmare yesterday:
| |/ Schloss Birlinghoven | My system started up with
53731 St. Augustin, Germany | ... Booting vmunix.el ...