Raw/unbuffered block device access

I need to do 2 things:
1) Disable the linux buffer cache, so all block device/filesystem reads will
go directly to the block device and not use any cache.
2) Do raw access to the block device (specifically an ide hard drive) without
going through a filesystem, but I want to be able to queue up reads to reduce
seek times.

There don't exist docs on doing either thing, or postings, or any help on
the internet anywhere that I can find. Any advice welcome!!!!!!!

-Dave

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