My previous disagreement turned on the idea that the host doesn't know a
RAID array is not a single physical drive.  With mirroring on MPE, the OS
still sees, at some level, multiple drives, but the file system does not - I
am conjecturing.

I am willing to concede that whether or not *any* mirrored disc setup can be
considered RAID depends on how transparent the mirroring is to the OS.  How
can we split this hair, though?  Is HP's mirroring on MPE a part of the OS,
or more like a driver?

I guess I don't really care which side it falls on.

For a description of the origin of the RAID technique, and other interesting
terms like SLED, see
http://www.amsstorage.com/html/raid_overview.html or
http://www.fibrechannel-europe.com/education/whitepapers/wp50.html

where I find support for your postulate that mirroring implies RAID.

-dtd


> -----Original Message-----
> From: Ted Ashton [mailto:[log in to unmask]]
> Sent: Monday, December 04, 2000 11:36 AM
> To: Dave Darnell
> Cc: [log in to unmask]
> Subject: Re: Mirrored Disk vs. Raid
>
>
> Thus it was written in the epistle of Dave Darnell,
> > Possibly, because on HP, two discs that are not part of an
> array can be a
> > mirrored pair, whereas RAID implies an array.
>
> Is an array of size two not an array?
>
> Ted
> --
> Ted Ashton ([log in to unmask]), Info Sys, Southern
> Adventist University
>
> ==========================================================
> The measure of our intellectual capacity is the capacity to
> feel less and
> less satisfied with our answers to better and better problems.
>                                            -- Churchman, C. W.
>
> ==========================================================
>          Deep thoughts to be found at http://www.southern.edu/~ashted
>