Hey,

I am trying to work out if I can use SANE on my old PPC 9500, and 
seem to be running into some issues. If there is anyone who answer 
  some questions about how the external SCSI bus works -- 
specifically if Apple engineered some idiot-proofing into it that 
SANE may not be aware of -- please let me know.

Here's what we're seeing: the external bus (this box has two built 
in) sees the scanner and tries to use it, but gets reset during 
the scan, and then it's lost until I restart it. There are some 
miscommunications between the scanner library (SANE) and the 
kernel: where the scanner says it's returning 161 bytes of data, 
we only get 160.

A related note from one of the developers who has been looking at 
this:

> A more general SCSI question: (I assume that the folks who adapted
> NetBSD to the Apple hardware know this, but let us be sure ;) The reason
> that Apple installs two SCSI busses in many of their computers is to
> have a fast internal bus for the hard disks; this bus needs the usual
> careful setup: proper cabling and termination; for the external bus
> Apple managed to design the interface in an amazing "error-friendly"
> way. I have seen several absolutely wrong setups working flawlessly,
> like a 1.5 m cable at the end of the bus without a device and without a
> terminator. This can only work for slow transfer speeds, so I wonder if
> the NetBSD kernel really ensures that the speed of the external bus is
> really 5 MHz. Do you see anything related messages with dmesg or in some
> log files?




-- 
Paul Beard
8040 27th Ave NE
Seattle WA 98115
206 529 8400

"Of ______course it's the murder weapon.  Who would frame someone with a
fake?"