Page 16 - slides.dvi

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Operating
Set
Need
of
Systems
kernel
Generally
interrupt.
require
OS
—
.
a
operating
.
secure
Applications
Kernel-Based
mode.
called
Structures
way
a
&
services
can’t
special
system
for
do
Protection
does
I/O
software
it
accessible
Operating
Priv
S/W
H/W
due
on
Unpriv
Mechanisms
application
via
to
(unprivileged)
App.
to
Kernel
their
interrupt
File System
App.
Device Driver
Systems
software
invoke
Scheduler
System Calls
since
behalf.
protection
App.
instruction
Protocol Code
Device Driver
to
App.
interrupt
operating
operates
allow
system:
similarly
mechanism
transition
to
a
called
from
real
user
system
to
(hardware)
12
calls.