Re: [PARPORT] ppscsi/epst mode question (slow scanning w/ hp5200C)

David Campbell (
Tue, 22 Jun 1999 13:49:39 +0800

<FontFamily><param>Courier</param>Date sent: Mon, 21 Jun 1999 22:16:22 -0400

From: Mark Thorp Duxbury <<>


Subject: [PARPORT] ppscsi/epst mode question (slow scanning w/ hp5200C)

<color><param>0000,0000,0000</param><FontFamily><param>Courier New</param>> The scanner works fine with the driver in mode 2 (for which I am very

> grateful) but is rather slow; around 4:30 minutes to scan a 300dpi color

> page. Under Windows 95 with the HP driver/backend it takes about 35

> seconds. I don't know how much, if any, of this performance difference

> is due to the ppscsi/epst drivers and how much is due to SANE.

</color>4min30sec => 270 sec versus 35 sec (ratio of 7.5) would suggest the
problem is more than just parallel port mode.

You have "delay" set to 1 which *may* be not be necessary, older
parallel ports have excessive capacitance which results in the output
pin being sluggish. Given that you have EPP support then you should
be able to reduce the delay. Further explanation requires some
knowledge of electronics and first order filters. [you might get 25-
100% performance increase with delay=0, your milage may vary
dependent on parallel port]<FontFamily><param>Courier</param>

Secondly the driver may be "optimised" for a range of devices
(scanners, CD-ROM drives, SCSI drives) for a workable solution.
Optimising the driver for a specific device may cause the driver to
fail for other device classes.

Just some thoughts on the issue.

David Campbell

"This is not an office, rather Hell with fluorescent lighting"

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