Re: [PARPORT] Syquest and printer [and Zip disk, to]

Matthew Vanecek (
Sat, 22 May 1999 07:00:14 +0000

David Campbell wrote:
> Hmm... I need to check the driver code but the symptom would match
> the ZIP drive grabbing hold of the parallel port and not letting go.
> You may want to check the /proc/parport entries and see which device
> the parport believes owns the parallel port.

Attached below is a script of the 'cat's of parport/0/*. Dunno if it
would help. Tim Waugh has copies of my dmesg/module loading output, but
I could run it again for you, if you'd like.

> When you say "if I then power off the Zip drive and power it on", is
> this while the ZIP disk is mounted (but no access). I am trying to
> figure out if this is a hardware or software issue (hardware would
> definitely be my responsibility, software would probably be something
> has slipped in the parallel port sharing code).

Doesn't matter if it's mounted or not. Once I insmod ppa, printing
stops. If I mount or don't mount, once I unplug and plug back in the
Zip's power cord, printing starts again. Until I do something that
accesses ppa/the zip drive, at which point printing stops again.

Of course, if the Zip is mounted when I power it off, I get an I/O Read
error when accessing the mountpoint, for some reason. ;)

> > I've only tried kernels 2.2.6 - 2.2.9. I've also tried Dave Campbell's
> > updated ppa.c/ppa.h/imm.*, etc, (which came out, what, yesterday?
> > Wednesday?) with exactly the same results.
> Friday morning (Australian time), there will some people who think it
> is still Friday night...
> > The problem is the same in both EPP and EPP+ECP mode.
> The problem will be mode independent, it is more a problem of either:
> a) ZIP drive has not gone back into pass through mode
> b) parport and dependent drivers has slipped a cog in the
> sharing code

Well, I wish I knew enough to help track the problem, but I'm only on
Ch. 4 of "Beginning Linux Programming" (Wrox Press). Now, if the driver
were (or could have been) written in COBOL...
I like option a, especially since I know nothing about the code in
option b.

Matthew Vanecek
Course of Study:
Visit my Website at
For answers type: perl -e 'print
For 93 million miles, there is nothing between the sun and my shadow
except me. I'm always getting in the way of something...

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