IBM 3745 Series, Hardware Maintenance Reference

Page: 357 / 712

MOSS States
Some states are viewed by the NCP or PEP (DOWN, OFFLINE, ONLINE). Other
states exist when the NCP or PEP is not loaded in the CCU (DOWN, ALONE).
Ÿ MOSS DOWN indicates that no program is running in the MOSS or that MOSS
IML is in progress. In this state the 'MOSS Inoperative' line is up and the CCU
interface is disabled.
Ÿ MOSS ALONE indicates that the MOSS microcode is loaded and operational
(CP not loaded).
Ÿ MOSS OFFLINE indicates that the MOSS microcode is running in the MOSS,
but that communication cannot be established with the NCP/PEP (except for
exchange with CLDP, and NCP/PEP initialization, which are part of the 3745
system IPL). In this state, the CCU is enabled.
Ÿ MOSS ONLINE indicates that the MOSS microcode is running and allows com-
munications with the NCP/PEP. In this state, the CCU interface is enabled.
(Numbers refer to the steps of “MOSS Changes of State”)
┌──────────────────────────────────────────────────────────┐
│ │
│ 9/2 ┌───────┐ │
│ ┌%──────────────────────────────────┤ │ │
│MOSS │ ┌────────────────────────────────5│ MOSS │ │
│IML │ │ 1ð ┌────────────5│OFFLINE│ │
│ │ │ │ │ ┌%─────────┤ │ │
│ │2 │ │ 4 │ │ 7 └─┬───&─┘ │
Power│ │ │ │ │ │ │ │ │
On │ │ ┌───┴─┴─┐ 1ð ┌───┴──┴┐ │ │ │
Reset│ └─5│ MOSS ├────────────5│ MOSS │ 4/5 │ │ 6 │
─────────5│ DOWN │%────────────┤ ALONE │ │ │ │
1 │ └──┬──┬─┘ 9/2 └──────┬┘ │ │ │
│ │ │ │ │ │ │
│ │ │ │ │ │ │
3 │ │ │ │ ┌─6───┴─┐ │
%────│ │ │ └%───8─────┤ │ │
Power│ │ └───────────────────────────1ð───5│ MOSS │ │
Off │ └%─────────────────────────────9/2───┤ ONLINE│ │
│ │ │ │
│ └───────┘ │
│ │
└──────────────────────────────────────────────────────────┘
Figure 8-5. MOSS Changes of State
MOSS Changes of State
The following is a description of the events and actions that cause a MOSS state
change. Step numbers identify events and actions in Figure 8-5.
Step 1. POWER ON RESET, according to panel option:
Ÿ Panel option = MOSS IML ('Function' = 1). The MOSS DOWN state
is entered during the time MOSS IML is performed, then MOSS
ALONE [10] is entered and is kept until further action.
Ÿ
Panel option = NORMAL or DISKETTE MODE. The MOSS DOWN
state is entered during the time MOSS IML is performed, then MOSS
ALONE [10] is entered, then MOSS OFFLINE [4], then MOSS
ONLINE [5]. This is the full system IPL.
Step 2. MOSS IML request at panel (Function = 1). The same sequence occurs
as in step 1 above, according to the panel option.
Step 3. POWER OFF. The full system leaves its current state.
Chapter 8. Maintenance and Operator Subsystem (MOSS)
8-9