Default Mass Storage Variable - HP 9000 Series 310 Service Information Manual

Default Mass Storage Variable
The boot ROM is responsible for setting up the default mass storage variable, DEFAULT_MSUS.
It is used by OSs for three purposes as the:
• Default MSUS for operating systems
• Device from which to load an AUTOSTART program, and
• Device from which to do a secondary load.
The DEFAULT _MSUS is set according to the following algorithm:
1.
Same as the MSUS of the booted OS for all but ROM OS, or
a. A non-ROM value passed in DEFAULT_MSUS to the booter routine (this is done
only by OSs calling the booter, not by the Boot ROM itself), or
b. The first device found with LIF, SDF, or UNIX formatted media present if ROM
is specified in DEFAULT _MSUS, or
c. The first device found present in the boot list if ROM is specified in DE-
FAULT_MSUS and no media can be found (i.e., an on-line disc drive with no media
present), or
d. A LIF media in an HP 8290XM drive at HP-IB 700 drive 0, if ROM is specified in
DEFAULT_MSUS and no devices are present.
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Boot Rom Functions