[sane-devel] Q: Performance Tip wanted, USB vs. SCSI HP 63xx Scanner

Peter Kirchgessner peter@kirchgessner.net
Sun, 25 Nov 2001 14:23:48 +0100

Hello Juergen,

I don't have a solution. But I can tell what's going on. The scan speed
of the scanner can not be reduced any more. The speed mode "slow" gives
the same speed as "auto" and "normal". Above about 200 dpi the scanner
generates more data than USB can transfer to the computer. Thus the
scanner must stop, move the carriage back and restart scanning. Thus per
move only a small strip can be scanned.

I would like to know what other scanners (Epson, Miicrotek,...) are
doing when scanning over USB ? Can they reduce their scan speed to avoid
stopping the carriage ?

BTW: I don't have problems with preview scan in xsane 0.81. It scans
continuously from top to bottom.


Juergen Sauer wrote:
> Am Freitag, 23. November 2001 00:19 schrieben Sie:
> > option enable-image-buffering
> Somewhat thing was what I'm looking for.
> It is not nessessary to have the same Device-Bandwith to the ram as with
> SCSI. Scanning time is not important. My topic is more to save the
> scanner's mechanical lifietime.
> But this did not helped here.
> During preview scan xsane .81+ sane 1.06 I recognize a ugly misbehavior:
> the scanner moves forward-stop-little backward-stop- etc. instead of
> moving counitnuesly until buffer full - stop transfer - go on.
> This behavior sounds like a cruel mechanical torture - HP's hardware
> quality is not the same as for a few years, this way the scanner will
> probably break soon.
> Any idea what's going on there - any idea ?
> mfG
>         Jojo
> --
> Jürgen Sauer - AutomatiX GmbH, +49-4209-4699, jojo@automatix.de **
> ** Das Linux Systemhaus - Service - Support - Server - Lösungen **
> http://www.automatix.de to Mail me: remove: -not-for-spawm-     **

Peter Kirchgessner
(alternate e-mail: pkirchgessner@t-online.de)