Manuel Bouyer wrote:
> 
> 1) what is really ultra2wide scsi (the one at 80MB/s) ?

U2W SCSI is also known as LVD (Low Voltage Differential) SCSI.
The main difference between the "normal" (aka Single Ended) SCSI is that
for each signal that is sent across the bus there are two wire. One wire
carries the signal in the same way SE SCSI do. The other wire carries
its logical inversion. (from here the name "differential")
This method increase the reliability of the data sent between the
peripheral and the host adapter (and vice-versa) allowing greater speeds
(up to 80MBytes/sec) and longer cables (up to 12 meters).

> does it uses the same cables as Ultrawide ?

The cables are of course different, but not the connectors which they
still have 68 pins.

> Can I mix ultra2wide and Ultrawide on the same bus ?

Some U2W host adapters like the AdvanSys ones, can let you plug U2W and
UW devices on the same cable. But this is not really a good thing to do
because you'll drop the speed of the faster device to the speed of the
slower device.

> 2) with a dual-channel scsi board, do we have twice the bandwidth (i.e. can
>    the controller manage I/O from both channels at the same time) ?

Yes

--
  Dante_