>I have the same problem with Mustek Paragon 1200SP and a NCR53C810 SCSI controler. Grey
>scan is faster or has the same speed as TWAIN and color scans may be make for each line
>a step back and is many times slower than M$ TWAIN.
I think it is quite clear this backtracking has not been caused by the SCSI
controller. Three types of controllers have been tested by me and other entrants
in this mailing list:
1. the supplied NCR53c400a ISA controller w/o IRQ
2. the suggested NCR53c810 PCI controller, with IRQ and bus-mastering DMA
3. an Adaptec AVA-1505 ISA controller, with IRQ, but without DMA
All SCSI controllers work with SANE and the mustek backend to control a Mustek
scanner, but still there is this issue of backtracking and hence, slow scanning
compared to Windows and TWAIN.
Now I think SANE and backtracking has two probable causes:
1. The driver (i.e. mustek backend) sends a strange command which confuses the
scanner.
2. The driver deliberately uses backtracking, to ensure image quality
(no dropped lines etc.)
I still hope to find the answer somewhere, as I can't figure out where it is
being done in the mustek backend, nor can I find some configurable option to
disable backtracking. Unchecking the "Force backtracking" box in xscanimage has
only effect in grayscale and lineart scans.
Cheers,
Robert
linux4me@dds.nl
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