Explain why asynchronous I/O activity is a problem with many memory protection schemes, including base/bounds and paging. Suggest a solution to the problem

Question

What will be an ideal response?

Answer 1

In
I/O
operation,
one
task
is
completed
while
another
task
is
in
execution.
Memory
address
checking
cannot
be
done
with
devices
such
as
base/bounds
registers
or
page
tables,
because
the
current
values
in
those
mechanisms
reflect
the
content
of
the
active
user,
not
the
user
for
whom
the
I/O
is
being
performed.
One
solution
is
to
check
accessibility
of
the
range
of
affected
addresses
before
commencing
the
I/O
operation.
However,
this
solution
is
ineffective
if
a
process
can
be
relocated
after
the
I/O
begins,
for
example,
due
to
a
page
fault
or
to
compaction
of
memory.