At 12:06 AM 5/26/2004, David Garamond wrote:

>When was shadowing first introduced in IB? Was RAID popular at the time?
>What is the original reasoning for shadowing and what is the future of
>shadowing?

Shadowing was added in Version 2, I think, in the mid-eighties as an
all but instant recovery system. At the time, if I recall, there had
been a rash of disks with bad fans, some sort of adhesive that let go
and trashed the platters, and similar problems. Though RAID hadn't
been invented (that I know of), DEC had some fairly sophisticated disk
management stuff with striping, shadowing, etc.

There are no plans to remove shadowing from the product.



Regards,

Ann
www.ibphoenix.com
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