Hello All,
The PDT (Page Deallocation Table) is a little different than the memory
error logs which are in the memlog file.
I am pretty sure that clearing the memory log file does not clear the PDT,
if it does, you can ignore the rest of this message.
Typically, if the memory logfile is cleared, the PDT info is added to the
memlog file when it is recreated by the memory logging process.
Is it possible that you really have double bit errors?
If so, a memory SIMM may need to be replaced. The PDT could be preventing
the system from failing due to double bit errors by allowing the memory
controller to skip the memory pages with the double bit errors.
I have attached an excerpt from the MPE/iX 5.0 communicator article
describing memory page deallocation.
Below are a couple of ways that you might be able to clear the PDT on a
Tclass system (99x) since there is not a PDC (Processor Dependent Code)
command specifically for clearing the PDT table.
Just to reiterate, it is possible that you need to replace a memory SIMM if
there are double bit errors that are causing memory pages to be deallocated,
but it is probably worth a try to clear the PDT, especially if you have
replaced a memory SIMM that had double bit errors.
Note: The commands below require MPE to be shutdown, and the 997 to be at
the Main Menu in the boot console handler (PDC).
First, go to the service menu and issue the SP (Show PDT) command to display
the PDT entries.
Try using the "toxic_flag_pd" command to disable the PDT, then use the 'RE'
cmd at the main menu to restart (or reset) the system and use the new
settings. Follow this by issuing the "toxic_flag_pd" to insure that the PDT
was disabled, then issue the "toxic_flag_pd true" to re-enable the PDT, and
issue the 'RE' command and verify that the PDT feature was enabled.
After re-enabling the PDT, go to the Service Menu and issue the SP (Show
PDT) command to verify that the PDT was cleared.
If this doesn't work, the other way we cleared the PDT when there was no PDC
command to do so was to power off the system, change the memory size and
power the system back up. When the memory size changes, the memory
controller will reinitialize the PDT and the memory error log (on the memory
controller).
This can be accomplished by powering off the system, removing a memory SIMM
(with ESD protection), powering up the system and then issuing the SP
command from the Service Menu to verify that the PDT was cleared. Once it
is cleared, power off, reinstall the memory simm that was removed (again
with ESD protection), power up the system, then go to the service menu and
verify the PDT size with the SP command, and also insure that PDT is enabled
with the "toxic_flag_pd" command from the main menu.
From the Tclass Installation Guide:
~~~~~start excerpt from Tclass Installation Guide~~~~~~
You should check the state of the PDT (enabled or disabled) using the
following
procedure to determine if it is properly set for the OS version running on
the
system.
------- Main Menu Commands
-----------------------------------------------------
Commands Available
PR Primary: Continue boot using primary boot path
RE Restart: Restart the system and activate new settings
Menus Available
BO Boot: Perform boot tasks (menu)
FI Firmware: Update firmware (menu)
SE Service: Service the system (menu)
TO Tomb: Display HPMC troubleshooting information (menu)
HE Help: Display help text on menu selections
-------
1. To display the current state of the PDT, enter toxic_flag_pd at the Main
Menu.
For example:
Main> toxic_flag_pd
PD - Enable Page Deallocation flag value is true
Main>
2. To enable PDT if it is disabled, enter toxic_flag_pd true. For example:
Main> toxic_flag_pd true
PD - Enable Page Deallocation flag value is TRUE
NOTE DO NOT ENABLE THE PDT UNLESS THE SYSTEM IS RUNNING
MPE/iX 5.0 or HP-UX 10.0 OR HIGHER. THE SYSTEM CANNOT
HANDLE DOUBLE-BIT ERRORS.
3. To disable PDT if it is enabled, enter toxic_flag_pd false. For example:
Main> toxic_flag_pd false
PD - Enable Page Deallocation flag value is false
4. If you change the PDT state, enter the command RESTART (RE) at the PDC
prompt to
perform a hard reboot.
~~~~~end excerpt from Tclass Installation Guide~~~~~~
Thanks,
Gary Robillard
-----Original Message-----
From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On Behalf
Of Craig Lalley
Sent: Monday, May 12, 2008 4:51 PM
To: [log in to unmask]
Subject: Re: [HP3000-L] Clearing Page Deallocation Table on 997-400
Michael,
I apologize, having used cstm before, I made the mistake that the program
might actual do what it says it was doing.
I tried, CL to clear the log, I tried SL to switchlog again "fail".
I am nothing if not persistant... so what I did was
go into posix
xeq sh.hpbin.sys -L
cd /var/stm/logs/os
mv memlog memlog_old to move the old file out of the way
touch memlog to build a new file
exit out of posix, and stop and start stm deamonn.
:stmshut.diag this will happen fairly quickly
:stmstart.diag --> This would be an excellent time to go to lunch or
go home for the evening
The next time you run logtool, you will only see new errors.
Sorry to have mislead you.
-Craig
Michael Hurdle <[log in to unmask]> wrote:
We are having double-bit memory errors reported each time we reboot our
HP3000 Series 997-400. We have been told that we need to clear the Page
Deallocation Table (PDT) but don't know how to do this. Can anyone on the
list help? Thank you.
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