[rescue] Netapp

[Patrick Giagnocavo]

On Tue, Jul 03, 2001 at 06:32:04PM -0400, Brian Hechinger wrote:
> On Tue, Jul 03, 2001 at 03:39:38PM -0500, Patrick Giagnocavo wrote:
> > They use one controller, with multiple IDE channels, each drive is on its
> 
> but isn't the big deal here that only one IDE device can talk at a time whereas
> all SCSI devices can talk at any time?  maybe that has changed about IDE, but
> i remember one of the old arguments against IDE (granted this was a while ago)
> was the bus hogging characteristic.

Each IDE channel can handle 2 devices.  Only one device can talk at one time.

So yes, there is the case that IDE devices can hog the bus.  This is why you
want your CDROM on a different IDE channel from your main hard drive; while
the CDROM is talking, nothing else can.

The other thing is that really, IDE is not a bus.  It is just a high speed
parallel(or is it serial?) interface.  The IDE protocol is so stupid that
they had to steal the most common SCSI commands and stick it on top of a
lame protocol to be able to easily support all the devices (Zip, CDROM,
CDRW, drives, etc.)

But, if you eliminate the brain-deadness by dedicating a channel to each
device, you eliminate the bus hogging.  Kind of like an ethernet switch
eliminates collisions vs. a hub.

./patrick