>
> Q1: Can I operate a scanner on the same SCSI bus as my CD-RW & Zip
> drives ? Will any SCSI-II scanner work ?
>
> A1: SCSI-I scanners hold on to the SCSI bus for times you
> can measure on a wristwatch. No other device connected to the same
> SCSI bus will work while you are scanning. If you do need to use
> other SCSI devices while scanning, you could end up with
> three or more SCSI busses on your machine: one for the scanner,
> one for slow-ish SCSI devices like CDRW, Zip and one for fast SCSI
> disk & tape drives.
>
> Seems like SCSI-II scanners should work, but I don't know
> if they do. With data rates in the 1 megabyte/s ballpark,
> they shouldn't be close to saturating a SCSI-II bus.
> If there's a problem, why is it there ?
>
> Or is SCSI I/II a red herring ? I thought SCSI-I devices
> were supposed to be able to disconnect/reconnect?
I don`t know any scanners that support disconnect/reconnect.
The UMAX Astras 1220S does not support it!
You are able to use the other scsi devices on the same bus with
the UMAX scanners. But I would NOT start a scan while burning a CD.
The UMAX scanners do block the scsi bus for some (1-3) seconds
at the start of the scan. While scanning the bus is not totally blocked
but it gets slower.
>
> Q2: Are there any well-known SCSI cards that I should particularly
> avoid ? What SCSI-card should I get ?
>
> A2: Don't use a scanner on an ultra-scsi bus. Expensive cables &
> active termination required. Problematic. Just don't think about
> it.
>
> Use a SCSI-II (Fast SCSI) PCI card, with a reasonably inteligent
> controller chip (e.g. 53C8xx, 53C9xx, Adaptec etc).
> Support for wide SCSI-II is not relevant - neither an advantage
> nor a disadvantage.
>
> The above comments apply equally to external CD drives, CDRW, Zip,
> and other scsi devices which don't need or support the speed of
> SCSI-III (Ultra-SCSI).
>
> Scanners (and CDRW) are often supplied with ancient ISA-bus SCSI
> cards.
> These cards should be disposed of with due care for the environment,
> or mounted on your wall.
>
The UMAX Astra 1220S normally comes with an ISA scsi card.
It does work a bit with linux but it really is not a good solution.
I suggest a good but relative cheap scsi card like the ncr/symbios logic
53c810 or 53c815 cards.
>
> Q3: What are the known problems with Linux Kernel SCSI support
> with regard to scanners ?
>
> A3: ?generic scsi support broken in 2.2.6-2.2.9 (!)?
> ?Kernels 2.2.10 & 2.0.37 OK?
> ?problems with old Advansys drivers ?
> ?problems with old Tekram drivers ?
> ?problems with some 53C875 driver versions?
> ?problems with some 53C810 driver versions?
>
Don`t know about kernel 2.2.6 or above, 2.2.5 works
but the other should also work!
The ncr-53c8xx (BSD) driver works well for the 53c8xx
cards you mentioned!
>
> Q4: Is it required or desirable to configure my Linux kernel
> in a non standard way ?
>
> A4: Basically no. You need to configure generic SCSI support
> and support for whatever SCSI controller(s) you intend to use.
>
> ??Changing SG_BIG_BUF may or may not help??
>
> Further information may be found in the doc for the backend
> for your scanner.
>
increasing SG_BIG_BUF helps til kernel 2.2.5
kernel-2.2.6 and above dynamically set the buffer size.
>
> Q5: Which scanner manufacturers - if any - provide or fund
> SANE (Linux) support ?
>
> A5: ? HP and Umax ? Complete guess.
>
UMAX published the scsi scanner protocol and
gives me scanners to test.
No help for parallel port scanners.
>
> Q4: Which backends are being actively developed ?
>
> A4: ?Umax, HP, Nikon?
>
> Difficult to tell. Microtek2 maybe. Agfa Snapscan maybe.
>
I am still working on the umax backend but there is not much
to do till a new scanner comes out.
Bye
Oliver
-- EMAIL: Oliver.Rauch@Wolfsburg.DE WWW: http://www.wolfsburg.de/~rauch
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