What happens if you connect two SAS controllers at their external ports?

[alternate]

I'm just curious... :) .

I'm wondering if it's possible for a 'guest' controller on a 'guest' computer to see the arrays of a host controller on a host computer, and reversely so. Can it be done for SAS controllers?

How about separately with SCSI controllers with other SCSI controllers? For example, having two SCSI controllers in a single bus. What would happen?

;)

[Paul Komski]

Guest and Host computers communicate through their individual operating systems and not directly via their hardware. The nearest you can get to accessing an array from one PC to another is by using Remote Disk Management and Dynamic Disks under the NT-based OSes starting with Windows 2000.

Or have I misunderstood the question?

[alternate]

I see. Without need for communication between the computers, though, if computers are connected to the same hard drives some way (on the same bus for SCSI or on the same expanders for SCSI (if this is possible), could the data on the hard drives be seen by both? One computer may have an OS on some of the hard drives, but the other will merely be connected to them...

[Paul Komski]

You cant share hardware in that way. Resources can be shared using network shares or by setting up a file server on a LAN - but even then the particular hardware is shared by an operating system (however rudimentary) and made available to the network. You cant have two differnt controllers from two differnt systems trying to control the same hard drive or array at the same time. Devices that can be hot plugged can of course be unplugged from one and then plugged into another but that is functionally no different that using a flash drive on two different computers.