4 Dec
2000
4 Dec
'00
10:24 a.m.
On Mon, 4 Dec 2000, Stan Sieler wrote:
Re:
But actually, don't they have the cart before the horse and it is really
a case of one form of RAID being mirroring?
- don
Sounds like a patent suit :-)
No...just an argument, really! (I'd mention if it was patent
oriented.)
This is kind of a specious argument. There were
volume shadowing (aka
hardware mirroring) products available before people started calling it
"RAID" and in fact the IBM DASD farms could do volume shadowing and it
isn't "RAID" because RAID is "Redundant Array of *Inexpensive*
Disks" and
3380's certainly weren't "inexpensive."
I dug up a copy of the original RAID article: "A Case for Redundant Arrays
of Inexpensive Disks (RAID)" by Patterson, Gibson, and Katz (from June,
1988).
They must have trained to be patent lawyers, because their definition
of RAID is verrrry broad! (To the point where software implemented
mirroring would still be called RAID1.) Basically, I found that if I tried to forget that RAID
was an
acronym with a meaning, I can see how people claim that any and all
disk mirroring is a form of RAID ... even if the mirroring preceded
the name "RAID".
BTW, I found a reprint of the article in "Readings in Computer
Architecture", edited by Hill, Jouppi, and Sohi,
published in 2000 by Morgan Kaufmann. This is a great reference
book. Articles include:
Architecture of the IBM System/360; by Amdahl, Blaauw, & Brooks
Parallel Operation in the Control Data 6600
The Cray-1 Computer System
Cray-1 Computer Technology
Cramming More Components onto Integrated Circuits; by Gordon Moore
wait...maybe there's a web site...
http://www.mkp.com/books_catalog/catalog.asp?ISBN=1-55860-539-8
Chapter 1 - Classic Machines: Technology, Implementation, and Economics
Chapter 2 - Methods
Chapter 3 - Instruction Sets
Chapter 4 - Instruction Level Parallelism (ILP)
Chapter 5 - Dataflow and Multithreading
Chapter 6 - Memory Systems
Chapter 7 - I/O: Storage Systems, Networks, and Graphics
Chapter 8 - Single-Instruction Multiple Data (SIMD) Parallelism
Chapter 9 - Multiprocessors and Multicomputers
Chapter 10 - Recent Implementations and Future Prospects
Highly recommended!
Stan Sieler sieler(a)allegro.com
www.allegro.com/sieler/wanted/index.html www.allegro.com/sieler