(
u --
a-addr )
a-addr is the address of the first character of the
block buffer assigned to block
u. The contents of the
block are unspecified. An ambiguous condition exists if
u
is not an available block number.
If block
u is already in a block buffer,
a-addr
is the address of that block buffer.
If block
u is not already in memory and there is an
unassigned buffer,
a-addr is the address of that block
buffer.
If block
u is not already in memory and there are no
unassigned block buffers, unassign a block buffer. If the block
in that buffer has been
UPDATEd, transfer the block to
mass storage.
a-addr is the address of that block buffer.
At the conclusion of the operation, the block buffer pointed to
by
a-addr is the current block buffer and is assigned to
u.