Bug#72479: Data Access Exception
Hunting through some dusty sun hardware manuals reminds me of the
following which may be causing my problem.
In the IPX there are 4 memory banks which can hold either a
1Mb (silly!), 4Mb, 8Mb or 16Mb SIMM (72 pin parity). The memory
is not contiguous and each block is mapped onto a 16Mb boundary,
creating memory gaps. The IPX which wont boot has 4 8Mb SIMMs making
My IPX which boots OK has one 16MB SIMM. Thus 0-16Mb is a contiguous
Maybe there is an erroneous hardcoded address which the RAMdisk
runs into by using direct physical memory access instead of
going through the MMU allocation procedures.