User`s guide

System Initialization and Acceptance Testing (Normal Operation)
4.7 Operating System Bootstrap
Table 4–5 MOP Multicast Addresses and Protocol Specifiers
Function Address
IEEE
Prefix
1
Protocol Owner
Dump/Load AB-00-00-01-00-00 08-00-2B 60-01 Digital
Remote console AB-00-00-02-00-00 08-00-2B 60-02 Digital
Loopback assistance CF-00-00-00-00-00
2
08-00-2B 90-00 Digital
1
MOP V4.0 only.
2
Not used.
4.8 Operating System Restart
An operating system restart is the process of bringing up the operating system
from a known initialization state following a processor halt. This procedure is
often called restart or warmstart, and should not be confused with a processor
restart which results in firmware entry.
On the KA52/53/54, a restart occurs if the conditions specified in Table G–1 are
satisfied.
To restart a halted operating system, the firmware searches system memory
for the Restart Parameter Block (RPB), a data structure constructed for this
purpose by VMB. (Refer to Table C–2 in Appendix C for a detailed description
of this data structure.) If a valid RPB is found, the firmware passes control to
the operating system at an address specified in the RPB.
The firmware keeps a "restart in progress" (RIP) flag in CPMBX which it uses
to avoid repeated attempts to restart a failing operating system. An additional
"restart in progress" flag is maintained by the operating system in the RPB.
The firmware uses the following algorithm to restart the operating system:
1. Check CPMBX<3>(RIP). If it is set, restart fails.
2. Print the message "Restarting system software." on the console terminal.
3. Set CPMBX<3>(RIP).
4. Search for a valid RPB. If none is found, restart fails.
5. Check the operating system RPB$L_RSTRTFLG<0>(RIP) flag. If it is set,
restart fails.
6. Write "0" on the diagnostic LEDs.
4–34 System Initialization and Acceptance Testing (Normal Operation)