HP 330 Service Information Manual page 163

Default Mass Storage Variable
The boot ROM is responsible for setting up the default mass storage variable, DEFAULT_MSUS.
It is used by OSses for three purposes as the:
• Default MSUS for operating systems
• Device fr01n which to load an AUTOSTART program, and
• Device fr01n which to do a secondary load.
The DEFAULT _MSUS is set according to the following algorithm:
1. Sanle as the MSUS of the booted OS, or
a. A non-ROM value passed in DEFAULT_MSUS to the booter routine (this is done
only by OSses 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.
Supported Boot Configurations
Listed below are all hardware interfaces over which the Boot ROM can boot an OS on all 32
I/O 8elect Codes where applicable.
• Internal HP-IB
(If
not present, external select code 7 is available for any of the other
interfaces. )
• HP 98624 HP-IB Interface Card
• HP 98629 SRlV[ Card
• HP 98625A/B HP-IB Interface Card (Except not with HP 8290X.)
• System Interface Board DMA circuits (displayed as DMA-CO)
• HP 98255 EPROM Card
• HP 98259 Bubble Memory Card
• HP 98262A High-Speed Disc Add-On
Interface protocols that can be used to boot an 08 with the Boot ROM are:
• C8/80
• 88/80
• Anligo
.8RM
• EPROM
• Bubble RAM
Boot ROM Functions
147