Aucbvax.4332
net.2bsd-bugs
utzoo!decvax!ucbvax!dist2
Thu Oct  8 19:17:22 1981
kernels with more than 56K of instruction space
       I could not get a kernel with an instruction space bigger than
       56K in size to load, even though we are running on a 11/70
       which has split I/D.  It appears that the last kernel I space
       mapping register was getting set to point to the I/O page
       regardless of the fact the we were running split I/D.

This is true and there is a very good reason for it to be done that
way.  If one loads a 407 or 430 file rather than a 411 one, the boot
program (kernel/src/cmd/standalone/bootstrap/boot.c) will unseparate
the kernel.  If KISA7 is not pointing to the I/O page, there will be no
way to access it (and no way to correct the mistake since all memory
management registers sit in that page).  Remember that in nonseparate
mode, all fetches go through instruction space.

                       Carl

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