Glossary 85
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PCI Express (PCI-E)
PCI Express (PCI-E) is an evolutionary upgrade to the existing Peripheral
Component Interconnect (PCI) bus. PCI-E is a serial connection that operates
more like a network than a bus. Instead of one bus that handles data from
multiple sources, PCI-E has a switch that controls several point-to-point serial
connections. These connections fan out from the switch, leading directly to the
devices where the data needs to go. Every device has its own dedicated
connection, so devices no longer share bandwidth like they do on a normal bus.
PHY
The interface required to transmit and receive data packets transferred across
the serial bus. Each PHY can form one side of the physical link in a connection
with a PHY on a different Dell-qualified SATA device. The physical link
contains four wires that for m two differential signal pairs. One differential pair
transmits signals, while the other differential pair receives signals. Both
differential pairs operate simultaneously and allow concurrent data transmission
in both the receive and the transmit directions.
Physical Disk
A physical disk (also known as hard disk drive) consists of one or more rigid
magnetic discs rotating about a central axle, with associated read/write heads
and electronics. A physical disk is used to store information, (data), in
anon-volatile and randomly accessible memory space.
POST
POST, short for Power-On Self-Test is a process performed before the operating
system loads when the computer is turned on. The POST tests various system
components, such as RAM, the physical disks, and the keyboard.
PERC H200.book Page 85 Tuesday, July 13, 2010 4:15 PM