Re: scsi controller for external devices

[Greg Madden <gomadtroll@gci.net>]

On Tuesday 28 March 2006 12:56, Francesco Pietra wrote:
> thanks a lot for pointing out the bottleneck. is that bottleneck also
> when no external device is attached to the scsi controller? i intend to
> connect the scsi chain to the workstation only occasionally for
> scanning and backup to have access to data by an ordinary pc. normally
> the scsi chain is connected to the pc.
>
> if the scsi controller causes a bottleneck per se, what about accessing
> the scsi devices attached to the pc from the workstation through the
> zyxel adsl rooter?
>
> i need that motherboard to get the best floating point for the money.
> with that workstation i am already at the lower limit to do ab inition
> quantum chemical calculations for large molecules.
>
> thank you again
> francesco pietra
>
> On Wednesday 29 March 2006 00:30, Greg Madden wrote:
> > On Tuesday 28 March 2006 10:25, Francesco Pietra wrote:
> > > tyan k8we
> >
> > Fast MB, unless you have all the  (external) devices left over, I
> > would't bother with fast scsi as I/O. With that board you have USB2,
> > Firewire 400, and with an add in card firewire 800. That card ad or
> > the devices attched to it becomes the bottleneck for perfornance. If
> > you have to go scsi I would get a cheaper card, I have used a Tekram
> > DC-315U and a SIIG AP-10, both supported by Etch.
> > --
> > Greg Madden

The card won't cause an issue when the devices are not being used. It is 
just when using the devices, with fast scsi you have to wait for the 
results, if applicable, of those operations. It all depends on what you 
do with your system, I.E. scanning high res color photo photos can create 
a large file that takes (x)time to transfer over scsi, while the USB2  
would transfer much faster 480Mbs or 60MB/s vs the 10-20? MB/s for fast 
scsi, same with a hard drive. Of course if you don't use those 
peripherals that much it isn't an issue.

-- 
Greg Madden