Control Data Cyber 170 Series Operator's Manual page 46

The following rules apply when performing a level 1 recovery deadstart.
1.
The DSD command CHECK POINT SYSTEM (refer to section
3)
must be issued
prior to the system malfunction. If a significant amount of system activity has
taken·place since the last checkpoint was performed, the checkpoint information
on mass storage. used in level 1 recovery. may no longer be reliable. If a check-
point is not performed prior to system malfunction. error messages will be issued
to the error log dayfile upon completion of a level 1 recovery deadstart (message
ROLLIN FILE BAD is common).
2. Memory dumps must be completed before level 1 recovery deadstart begins
since memory confidence testing destroys the contents of both central memory
and PPUs.
3. The mass storage equipment configuration must be the same as specified during
the most recent level
0
deadstart, that is, the same CMRDECK must be used.
4. The system devices (mass storage devices on which the system library ·resides)
must be the same as specified during the most recent level 0 deadstart.
5. The LIBDECK selection, if specified via the deadstart panel. must remain the
'same as specified during the most recent level
0
deadstart. If the LIBDECK
is specified in the CMRDECK, it would automatically be selected (refer to
item 2).
It
is recommended that the operator stop current system activity prior to beginning the
system deadstart procedure (that is, before activating the deadstart switch). To acconl-
plish this, the operator should attempt entry of the following DSD commands.
1.0NSWl.
I. STOP.
IDLE.
CHECK POINT SYSTEM.
UNLOCK.
STEP.
LEVEL 2 RECOVERY
Enters all time- sharing users into recovery state. This
and the following command are necessary only if TELEX
(time- sharing executive routine) is active.
Drops TELEX
Idles active control points and prevents scheduling of new
jobs to a control point.
Rolls out all jobs with a queue priority less than or equal
to MXPS (maximum queue priority for user jobs) and
writes the contents of central memory tables to mass
storage. Jobs with queue priority greater than MXPS
(TELEX, BATCHIO, etc.) cannot be rolled out.
Necessary only if console is currently locked.
Prevents the system from processing PPU requests.
This stops all central memory I/O operations.
Level 2 recovery deadstart is normally used in system test situations and is not 'recom-
mended for the normal production environment. If level 2 recovery is selected,
all jobs and active files are recovered from checkpoint information on mass storage as
in level 1 recovery. However, no attempt is made to recover the system. Instead,
the system is loaded from the deadstart tape as in level
0
deadstart. Note that sys-
tem loading cannot begin until system initialization (entry of date and time) has been
performed. In all other respects, level 2 recovery is identical to that described for
level 1 in the preceding description, and all rules apply.
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