Installation guide

1
Installing the HBA into Your Server
1-7
Installation and Configuration
Figure 1-3 Figure 2- HBA edge connecters
PCI-X (or PCI Extended) slots increase the speed that data travels
over the bus. PCI-X slots appear identical to a 64-Bit PCI slot keyed
for 3.3v (see number 3 in Figure 1-2 on page 1-6 and Figure 1-3 on
page 1-7.) PCI-X slots are backwards compatible with 3.3v PCI HBAs
and universal HBAs. Inserting standard PCI HBAs into PCI-X slots
will lower the bus speed, however, as they cannot take advantage of
the improved performance.
PCI-X 2.0 is the next generation of PCI-X buses. PCI-X 2.0 increases
the bus speed providing more performance for HBAs. PCI-X 2.0 slots
also appear identical to a 64-bit PCI slot keyed for 3.3v (number 3 in
Figure 1-2 on page 1-6 and Figure 1-3 on page 1-7.) PCI-X 2.0 is also
fully backward-compatible with 3.3v PCI and PCI-X.
PCI Express (sometimes noted as PCIe) is a new bus type that uses
the existing PCI model, but implements it in a faster, serial protocol.
Because of the serial way it transmits data, the PCI Express bus slot
can be different sizesdepending onthe throughput it supports. PCI
Express slot speeds are expressed in "lanes" and are normally shown
as x1, x4, x8, and x16. Each type of slot are different lengths
(Figure 1-4 on page 1-8) and HBA edge connecters will also be of
varying lengths depending on how many lanes they require for
throughput. Because of how PCI Express slots are keyed, a x1 HBA
can be inserted in all 4 slot types as the HBA will negotiate with the
slot to determine the highest mutually supported number of lanes.
An HBA requiring x16 lanes will not, however, fit into a smaller slot.