Re: R.A.I.D boxes

In article <39ujvh$cv1_at_crl5.crl.com>, Dick Wilmot <dwilmot_at_crl.com> wrote:
>mew_at_world.std.com (Michael E Willett) writes:
>
>>RAID 3 fails on small reads and small writes and RAID 5 handles large and
>>small writes poorly, while RAID 7 ... ^^^^^^
>
>Actually, a RAID 5, the Maximum Strategy Gen 4 (which is resold by IBM as the
>9570) does large writes as fast in RAID 5 mode as in RAID 3 mode and does
>large reads faster in RAID 5 mode than in RAID 3 mode. At a sustained rate of
>about 90 megabytes/second the Gen 4 is the highest bandwidth disk array of which
>I am aware and it is fastest in RAID 4 mode.
>
>The Gen 4 is intended to storage serve Cray and other large supercomputers for
>scientific workloads. In the less stratospheric regions are subsystems like
>the Mylex DAC960P. The DAC960P-3 can sustain 20 megabytes/second for long
>sequential read operations using seven disk drives each capable of three
>megabytes/second media transfer rate or, with EDRAM cache memory and 4.3
>megabytes/second drives the controller can sustain 30 megabytes/second.
>Since Mylex sells primarily through OEMs such as IBM, HP, Storage Dimensions,
>etc.
>
>It would certainly be interesting to know the maximum SUSTAINED bandwidth
>achievable some other subsystems. Effective (street) price is also an
>interesting aspect. Customers seem to be interested in $/MB, $/IO and
>reliability.
>--
> Dick Wilmot
> Editor, Independent RAID Report
> (510) 938-7425

Can someone tell me what RAID 7 purports to be, I have heard of and seen RAID 0 RAID 1, RAID 3, and RAID 5, I know what RAID 2 and 4 are, but what is RAID 7. Is this a new level or a new marketing gimick, like many others out there?. If it is real, how does it differ in detail from the others in any significant way.

-- 
|           /\       |Tom Pennington tompenn_at_info.census.gov|
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