plustek@linuxhacker.org

plustek@linuxhacker.org


Subject: about Parport communication issues
From: MRZ
Date: Thu, 7 Jun 2001 13:12:46 -0700

> Gert Menke wrote:
> 
> > Hi!
<snip>
> > And doing something else while scanning does not seem to slow down the scanning
> > speed.
> >

To which Mark Bratcher replied:
> This appears to be one of those YMMV things.
> I have a 9636T on a Pentium II/233MHz system. It simply won't work with EPP
> enabled. Gets a corrupted image every time. SPP works great. SPP was recommended
> to me by Gerhard Jaeger.
> 
> Mark

I don't know about about that YMMV part; there may be more to this than than everyone
thinks.  I too have a 9636T,  hanging off the pp of a debian potato (2.2r) box. While
I have  no "problems" using EPP mode, I have noticed some quirks. As it's a PIII-550MHz
with 256MB RAM I wouldn't expect there to be a lack of resources, but when I'm anywhere
in the scan process my system does seems to experience something of a slowdown and resources
seem to get *absorbed*. When the scan process is totally over everything goes back to
normal.

It is possible that this is a symptom of the same problem that causes a corrupted image
for Mark. Perhaps in my case the additional system resources make the difference. In
fact I think I've seen the kind of behaviour before in other unrelated areas. Specifically
it had to due with how interrupts are handled, and might be caused by the way pp and
IDE signaling work.

It isn't a problem at all for me so I've never gone that extra step; but it might be
worthwhile to see what happens if the box is using SCSI storage media rather than IDE
(IDE being where I've seen this behavaiour).

Marc.


plustek@linuxhacker.org