380
Networking Fundamentals
Automatic
Confi guration and
Power Interface
(ACPI)
a standard for
controlling the power
options for computer
hardware devices.
Through the use of edge expander devices, a maximum of 16,000 SAS devices can
be connected.
ACPI and ACPICA
Automatic Confi guration and Power Interface (ACPI) is a standard
for controlling the power options for computer hardware devices. The fi rst
implementation of the ACPI standard gave users the ability to select how they
wanted their computer to behave to conserve power. For example, the user could
confi gure the computer or individual computer devices to go into a state of
hibernation after a period of inactivity.
Figure 9-13 shows the power options available for a wireless network
adapter. These options allow the computer to turn off the adapter to save power
and allow the adapter to wake the computer when network activity occurs.
Figure 9-11.
The SCSI limit of
seven devices can be
expanded by using
expander cards.
Each expander card
allows an additional
seven devices to be
connected to the
SCSI system. LUN
numbers are assigned
to the additional SCSI
devices so they can
be identified by the
system software and
BIOS.
Device location
equals SCSI 6,
LUN 3
Expander card
SCSI card
Expander card
0
1
2
3
4
5
6
0
1
2
3
4
5
6
0
1
2
3
4
5
6
SCSI ID
numbers
LUN ID
numbers
LUN ID
numbers
Figure 9-12.
SAS and SATA disk
drive connectors.
Notice the two
connector types are
similar.
SATA
SAS