Page 86 - slides.dvi

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1.
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3.
I/O
Operating
OS
to
to
from
to
Many
(last
can
block
single
Systems
double
circular
Buffering:
—
cope
cope
network
use
character
devices
I/O
aspects
OS
maintain
usually
Buffering
with
with
devices
of
buffers
buffering
devices
buffering
⇒
Subsystem
various
devices
—
stores
“copy
—
major
⇒
—
device
device
⇒
lots
(its
OS
kinds
user
buffering
of
most
line
of
bursty
speed
of
own
process
transfer
fixed
semantics”
assigns
useful
(time
a
copy
dictated
size
buffer
size
for
probably
&
by
buffering:
of)
mismatch
consumes
system
bursty
data
space).
memory)
device
from
mismatch
transfers.
in
sufficient.
I/O
buffer
one
type:
to
memory
the
buffer
user
while
while
request
system
transferring
fills
to
the
or
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