What are postbl and rotbl?

[Michael L. Powell]

Can someone explain what the values in fs_postbl and fs_rotbl are?  I know
approximately what they are for, but looking at the values set up by mkfs
and looking at the code in ufs_alloc.c doesn't provide much help.  When I
try configuring a pseudo-disk with nice parameters, I get values that do
not work (i.e., alloccg panics when it cannot find blocks that are in fact
available).

Consider, for example, an rm05.  The first entry of postbl is 0 and the rest
are -1.  Rotbl contains 36 2's (followed by some number of 0's?).  In case it
helps, this is a standard root file system.

The values for an ra81 are even more bizarre.

					Michael L. Powell
					Digital Equipment Corporation
					Western Research Laboratory
					100 Hamilton Ave
					Palo Alto, CA  94301
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					powell at decwrl