Here is how the maps work:

Each map is a 4K (by what?) ram.  

The level 2 map is what maps virtual addresses to physical addresses.
The level 2 map has two halves, the page half and the control half.  The
page half maps the virtual address into a physical address and the
control half contains bits indicating the status of the page (e.g.
swapped in, written, read-only, etc.)

The virtual address is 25 bits long.  The low 8 bits are the offset
within the page and are not mapped at all.  The next 5 bits address
the level 2 map directly.  The top 12 bits cannot address the level 2
map because the level 2 map only has 4K entries in it.  The top twelve
bits go into the level 1 map which contains level 2 map addresses.  The
level 1 map thus addresses 32 page chunks of the level 2 map.  You can
only address 128 32-page chunks of level 2 map space, so all but 128 of
the level 1 map entries are valid.

Okay, I lied.  One of the 32 page chunks of level 2 map space is set up
to always fault.  Any invalid level 1 entries will point to this chunk.
A few are also tied to "wired" map entries (these are entries pointing
to the physical memory that is used for getting through map faults).
It is the last chunk which is the level 1 map miss indicating chunk.

The L1 map meta-bits are a function of the region.  Since each L1 map
entry corresponds to 32. virtual pages, this means regions must be at least 32 pages, etc.
This is no further restriction, since the address space quantuum was already 64 pages.

       LAMBDA					EXPLORER

10,11 hardware generated parity         11: l1 map oldspace bit
					10: l1 map valid bit
 9: volatility-invalid-bit		 9: 
 8:  volatility-bit			 8: volatility-bits
 7:  volatility-bit			 7: volatility-bits
 6:					 6:
 5:					 5:
 4:					 4:
 3: l2 map address inputs		 3: l2 map address inputs
 2:					 2:
 1:					 1:
 0:					 0:

The level 2 page map entries are boring, they just produce the high 24
bits of the virtual address (the low 8 bits coming from the VMA)

The level 2 control map is more interesting.

10: read access if force		10:
 9: hardware read access		 9:
 8: access-code/status code		 8:
 7: status code				 7:
 6: status code				 6:
 5: oldspace bit			 5:
 4: extra-pdl				 4:
 3: representation type			 3:
 2: representation type			 2:
 1: volatility bit			 1:
 0: volatility bit			 0:

The page hash table is the authority on pages that are swapped in to
memory.  If there is a map fault, the page hash table is looked at to
see if there is a page fault.

Page hash table info

First word.

26 - 31: not used
8 - 25: virtual page number
6: valid bit
5: page modified bit
3 - 4: page age
0 - 2: swap status code

Second word.

31: access code
30: access/status code
28 - 29: status code
27: oldspace meta bit
26: extra-pdl meta bit
24-25: volatily bits
0-23: physical page number

Map faults:

When we get a level 1 map fault, we throw away a section of the level 2
map and make the level 1 map point to it.  When we go around again, we
get a level 2 fault which causes the level 2 map to reload.