FireWire questions.

[Les Mikesell]

On Fri, 2005-01-07 at 02:28, Naoki wrote:

> What exactly is the SBP2 driver and why is it needed for FireWire? 

Firewire does lots of different stuff.  The sbp2 module inserts
a software interface for disk devices.

> I've
> just picked up a very simple firewire disk enclosure for some testing
> and noticed the manual says I need the raw1394 and sbp2 drivers.
> Wondering if FC3 will see it with the default kernel.

It is supposed to.  I have one that doesn't work right (and it does with
FC1) but I think it is specific to the chipset in my enclosure - but
even then the modules load and identify the device automatically.

> Off topic question : 
> UltraScsi III does 320mb/sec which is all well and nice but scsi being a
> million years old need pre-allocated ID and termination, max 16 devices
> etc etc.

Scsi drives tend to be more intelligent about accepting multiple
commands and sorting into the fastest order of operation, and
on server systems where it matters the 80 pin hot-plug SCA interface
lets the backplane take care of drive select and termination.

> FireWire on the other hand does 400/800mb/sec and can not only support
> 63 devices but you can daisy chain and it doesn't need termination. On
> top of that you can daisy chain up to 1023 buses together. 
> 
> So, why is scsi still alive?

The command queuing is important on multiuser/tasking systems, but in
general it is probably just that Apple is the only vendor that includes
the connector on everything.

-- 
  Les Mikesell
   les at futuresource.com