Service manual

Power-Up 2-13
During phase 1, “remote” testing of each QBB in the system is conducted if
there is more than one QBB in the system. Remote means testing of hardware
by a system primary CPU, selected by the SCM from data collected in phase 0,
across secondary (global ports) and the hierarchical switch if present.
Initial soft QBB IDs are assigned in this phase. (Soft QBB IDs may change
during power-up if something fails.) Soft QBB IDs are necessary to make sure
that good memory exists at address 000.0000.0000, a requirement of Tru64
UNIX. Since it is possible that hard QBB 0 may not have good memory, soft
QBB ID 0, which will contain memory space address 000.0000.0000 by
definition, is assigned to a QBB that has good functioning memory. As a result
software uses a soft address that points to a hard address that may be different.
At the end of phase 1, the following is known:
• The soft and hard QBB IDs of all functioning QBBs in the system
• Whether there were self-test errors on CPUs, PSMs, DTags, DIRs, IOPs,
and memory
• Whether the QBB switch, the global port, the I/O path to the PCAs, and the
hierarchical switch work
• The configuration of all QBBs
• The location of any standard I/O modules (SIO)