3Com e-PC c10/s10, User Manual, Page: 25 / 122

C C h h a a p p t t e e r r 3 3 1 1 3 3
UNDI Execution
UNDI code in ROM with
MBA base code in ROM
on NIC enabled UNDI code in ROM with
MBA base code in ROM on
NIC disabled UNDI code in ROM with MBA
base code in BIOS
UNDI uses base code on NIC UNDI tries to locate and use
another PXE-compatible base
code (which could reside in BIOS) UNDI uses MBA base code in BIOS
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If your PC was purchased recently, it may be Plug and Play BBS-BIOS (BIOS Boot
Specification) compatible. A PC that supports Plug and Play can automatically detect and set
up devices such as CD-ROM drives, hard disks, and NICs. The BBS specification (developed
by Compaq, Phoenix, and Intel) specifies how the system BIOS identifies boot devices in a
PC, allows the user to select the boot order of these devices, and then sequentially attempts
to boot from each device in the specified order.
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E : : PC manufacturers may call their BBS support by other names such as
Multiboot.
PCs that are Plug and Play BBS-BIOS compatible allow you to specify the boot order in the
PC’s BBS-BIOS Setup menus. Because these BIOSs can detect the existence of MBA UNDI,
you can specify the position of MBA UNDI in the boot order with respect to the other boot
devices. If you want the PC to always boot from the network first, be sure to put MBA UNDI
at the top of the boot order list. You can also use the MBACFG utility to make MBA UNDI first
in the BBS boot order. MBACFG provides a menu command that makes MBA UNDI the first
boot device.
If the PC's BIOS is not BBS-compliant, MBA UNDI attempts to control the boot process (this
behavior is configurable with MBA UNDI) and perform a network or local boot, depending on
the configured options.