Rod Speed wrote:

Even SCSI doesnt allow the use of all 4 drives simultaneously anyway.

Sure it does. SCSI allows all drives to be used simultaneously;
up to 7 HDs on a narrow bus and up to 15 HDs on a wide bus. E.g.,
SCSI allows the initiator (the Host Adapter) to issue a read command
to each target (HD) and then disconnect from the SCSI bus; each HD
may then, concurrently, do the seek, then read data from the platter
into its buffer, and reconnect only when it is ready to copy data
into host RAM. This capability is one reason why it makes sense to
use a 320 MB/s (U320) version of SCSI to attach HDs which have STRs
of less than a quarter of the bus data rate.

Moreover, with command queuing, a bunch of read commands can be
issued to each HD, and each HD can execute them out-of-order and
briefly re-occupy the SCSI bus to do the actual data transfer.
And yes, it works the same way for writes and for mixtures of
reads and writes.

I am not claiming that WinWhatever takes full advantage of the
capabilities of SCSI, but there are grown-up OSs which do.
--
Cheers, Bob