[comp.sys.ibm.pc] Cache control on 386 PC/AT compatibles

davely@mcrware.UUCP (Dave Lyons) (11/08/89)

	I'm looking for any information available on how to enable/disable/
flush the 64K cache on a 386 PC/AT compatible.  The particular machine
we have is a Gateway 2000.  Please e-mail me any information you might
have as I don't regularly read this group.

Thanks for any help, Dave Lyons

-- 
 Dave Lyons - ...!sun!mcrware!davely  | On Second though let's not go to
 My employer laughs at my opinions.   | Camelot... 'Tis a silly place
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jrh@mustang.dell.com (jrh) (11/08/89)

Most 386 systems that use the Intel 82385 cache controller will allow an 
application to disable the cache.  In general, to avoid caching a memory
space, make sure the highest bit of any address (A31) is high.  This will
help with adapters with memory-mapping, with page swapping or dual-port
memory schemes which may not like the memory space on the I/O channel being
cached.  Because A31 does not go to the I/O channel and other address lines
are the same, the adapter will respond normally.


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James R. Howard
!s: cs.utexas.edu!dell!mustang!jrh