HP ProLiant DL985 Introduction Manual page 8

The PCI Express specification also defines two other PCI-like form factors. A PCI Express Mini Card,
similar to the Mini PCI card will include a x1 connector for use in portable products. The ExpressCard
is similar to PCMCIA cards and will include a x1 PCI Express connector and a USB 2.0 connector for
use in desktop and portable products. (See Figure 8.)
Figure 8. PCI Express Mini Card (left) and Express Card (right) form factors
In addition to these evolutionary PCI-like form factors, the PCI Express specification will define a
revolutionary server I/O module (SIOM). The SIOM has the potential to add customer value because
it allows inserting and removing cards from outside the server chassis. The SIOM is mechanically
rugged and it simplifies insertion and removal by providing guide rails with a blind-mate connector
at the end. It also protects the card with a physical shell and provides well-defined airflow
characteristics. However, because of the radical mechanical differences between SIOM and standard
PCI and PCI Express cards, it is unlikely that SIOM will be implemented in standard server designs.
The most likely application for SIOM will be in enclosures specifically designed for modular I/O
expansion, such as an enclosure full of SIOM cards (Figure 9).
Figure 9. Server I/O module
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