Paul G. Allen wrote:
On Tue, 2007-08-14 at 14:12 -0700, Carl Lowenstein wrote:
On 8/14/07, kelsey hudson <[EMAIL PROTECTED]> wrote:
Ralph Shumaker wrote:
Would a SCSI transfer be quicker between two disks on one controller or
on separate controllers? If memory serves me, I think I remember
something about SCSI being able to simultaneously copy one disk to six
others all at the same time while barely touching the CPU or system
memory. Is this even close? (Memory may be foggy, and I may have
misunderstood it to begin with.)
Faster? Maybe. SCSI *can* busmaster, true. And, the controller can be
programmed to do what you say.
You know, this is true in principle. But software support to send the
appropriate commands to the SCSI devices is scarce to non-existent.
It's unfortunate that the industry mangled what SCSI was designed for.
It was not designed just for connecting scanners and hard drives to a
computer. It was designed to connect *any* device with a SCSI interface
to a common system bus. The SCSI bus was designed to allow multiple
hosts and every device could become a host or a slave. In 1988 I
designed a video system (while I still worked at NCR, the folks that
brought us SCSI, but it was not done for NCR) that had a SCSI interface
on board so that it could load video data directly from disk, bypassing
the host computer. Such a system would have a minimum of two hosts - the
host computer and the video system - and multiple slaves.
To this day I'd still like to see video systems with smart peripheral
interfaces on them. It would greatly speed up system performance.
As Carl stated, software to do such things is scarce to non-existent,
thanks to the limited adoption of SCSI by the industry.
PGA
Is that why SCSI HD prices always stayed higher than IDE? Controllers
too? I don't think the limited adoption of SCSI was as much determined
by industry as it was by the market, unless industry was artificially
keeping SCSI prices high. But why would they do that?
--
Ralph
--------------------
How do you test an uncooperative intelligence when it's smarter than you?
--Stewart Stremler
--
[email protected]
http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
