This message is from the T13 list server.
Sheffield, Robert L wrote:
This message is from the T13 list server. Read cache and read look ahead are decidedly different concepts.
So you are also saying there is no documented way to disable read caching in an ATA drive? It is only possible to disable the "read look ahead" part of some more complex "read caching" algorithm?
Both functions consume buffer space in the drive, but the similarity ends there.
Maybe it is time for all of us to dust off some of those computer journals from the 1950's are read about "computer data caching"?
Having worked on caching algrorithms for various types of storage devices for something like 30 years, I find this discussion a little strange. I've never heard anyone describe "reading ahead" or "staging" data to be something different from data "caching" and/or something that is not part of a well designed data caching algorithm.
I think if you really intend that a disk drive separate "read ahead" from a more robust "read caching" algorithm then you need to have a serious conversation with some of the people that design and implement these algorithms in disk drives.
Hale -- ++ Hale Landis ++ www.ata-atapi.com ++
