GEOM and CAM pass behaviour

[Jack]

Hi all,

I would like to know 2 things regarding geom and cam pass driver
behaviour. It would be helpful if someone could educate me regarding
this.

Consider the case where a scsi/ata tape/hard drive is attached to the
system after the FreeBSD is booted(from different drive) completely.


1. Is it true that GEOM layer will always taste the (hard drive/tape
drive)device whether we access device via cam pass driver or do block
access. In other words, say if we never do a block access on the
selected device, and we only access this device via cam pass driver,
will then Geom will ever have to taste(e.g. for partition table, etc.
or for other purposes) this
device.?

or is it something like, as soon as the device is attached, geom layer
will always taste it - it doesn't matter how we access the  device.

2. Also, is it possible that while a process is accessing the selected
device via cam pass driver, the block access is also possible at that
same time, (by same or different process) to that same device.
I know that when a process is accessing the device via block access,
it is possible for another(or even same) process to access that same
device via cam pass driver, but I would like to know whether the other
way is true also.


Thanks.
-- 
Jack