DEC 7000 AXP Operation Manual page 89

The virtual unit number of the load device is 8DAC, where 8 indicates
1
shadow set booting is used, and DAC is the hexadecimal value of the
virtual device unit number of 3500 (decimal). This value is passed to
bits 16–31 of General Purpose Register R3.
The system root is 2, which are bits 28–31 of General Purpose Register
2
R3.
The VMB option is 0 as listed in Appendix B, which are bits 0–27 of
3
General Purpose Register 5.
The device search list contains dua3500, which is the virtual device,
4
and dua63, which is the physical device. The console first attempts to
boot from the virtual device followed by the physical device.
The device node is 14. The path through HSC 14 will be tried first.
5
The device channel number is 0.
6
The XMI node number for the I/O adapter module is 12.
7
The I/O channel number is 1.
8
The parameters for the physical device are the same as the virtual de-
9
vice except that the device unit number is 63.
For more information:
VAX Volume Shadowing Manual
VMS Upgrade and Installation Supplement:
VAX 7000-600 and VAX 10000-600 Series
Booting 4-41