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Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

 
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Rajarshi Gupta
Frequent Advisor

Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

Hi,
Pleas let me know how could I get the '>>>' savron prompt in VAX4100 server when I did shutdown with out pressing the Console HALT button or F5 on the keyboard. Write now the console is getiing stuck giving the message 'Use console to Halt the system' after the shutdown.

Thanking You
8 REPLIES 8
Karl Rohwedder
Honored Contributor

Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

You had to press the hardware HALT button, I think a VAX4000-105 has it on the backside.

The 'normal' OPCCRASH.EXE has not the ability to really HALT the system. I have slight memories of unsupported ways of doing that...


regards Kalle
Rajarshi Gupta
Frequent Advisor

Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

Hi kale,
Thanks for your answere.But I am looking for any environmental settings from >>> prompt, which can give me the >>> prompt back without pressing the console halt button at back of the server or the F5 key.
Art Wiens
Respected Contributor

Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

You can try a p , although I'm not sure that worked on the 4100's.

Let me guess, your machine is in a rack or on a shelf and you can't physically get to the back of the machine easily?

I arranged our's "backwards" given that the number of times I might need access to the cd is never, and if I do, I get the ladder and climb over the top.

Cheers,
Art
Volker Halle
Honored Contributor
Solution

Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

Rajarshi,

this is default behaviour of OpenVMS VAX.

The operating system enters an infinite loop (BRB .) after printing the 'Use console to halt the system' message when shutdown is complete and you need to press the HALT button or Break or CTRL-P (depending on the type of VAX system) to finally halt the CPU and get to the 'chevron' prompt >>>

This code is in module [SYS]BUGCHECKLD and I remember having produced patches for various versions of OpenVMS VAX to replace the BRB . instruction with a HALT. This was used to HALT VAXstation satellites in a large distributed cluster to allow them to be boot-triggered via MOP and thus relieved the system managers from running around the factory to HALT about 80 VAXstation satellites in case of a cluster shutdown.

The patch is incompatible with the >>> SET HALT RESTART console setting, as this would cause the console to try to restart the operating system if the CPU is unexpectedly halting.

If you are really interested in this UNSUPPORTED patch (to SYS$LOADABLE_IMAGES:EXCEPTION.EXE), I can certainly try to dig up the details...

Volker.
Rajarshi Gupta
Frequent Advisor

Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

Volker,

Please dig into it and provide me the required patch.

Thank you Very much
Volker Halle
Honored Contributor

Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

Rajarshi,

first of all, which version of OpenVMS VAX are your running ? What's the link date and time of your SYS$LOADABLE_IMAGES:EXCEPTION.EXE file ?

If I talk about a 'patch', this means PATCHing the SYS$LOADABLE_IMAGES:EXCEPTION.EXE file with the OpenVMS PATCH utility and replacing the 'BRB .' instruction with a 'HALT' instruction and creating a new version of that execlet.

To do this, I need to find out the address offset of that instruction in YOUR version of EXCEPTION.EXE, this address it's NOT in the symbol table !

This is not like your typical @VMSINSTAL of an OpenVMS ECO patch kit ;-)

Volker.
Rajarshi Gupta
Frequent Advisor

Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

Volker,
The open VMS VAx version is 7.1 and the SYS$LOADABLE_IMAGES:Exception.EXE was built on 10-DEC-1996.
Hope thsi will be helpful.
Thanks
Volker Halle
Honored Contributor

Re: Saveron Prompt ' >>>' for VAX 4100 - 105/106 server

Rajarshi,

first of all, you need to find the 'BRB .' instruction in the EXCEPTION.EXE execlet in the running system:

$ ANAL/SYS
SDA> SHOW EXEC
...
EXCEPTION 8180E800 81818E00 0000A600
...
SDA> EXA/INS +52D3 ! first addr from above line

If you see:

EXCEPTION+052D3: BRB EXCEPTION+052D3

you've found the 'BRB .' instruction. If not, you have to poke around with SDA (by varying the 52D3 offset) to find the appropriate instruction (there should be no other 'BRB .' instruction in this execlet).

You can also use SDA> EXA/INS address;20 to examine a range of instructions, so you don't have to issue too many single EXA commands. NOTE: VAX instructions are VARIABLE LENGTH, so it's best to find the start of a real instruction stream and work forwards instead of backwards.

Once you have found the offset of the 'BRB .' instruction, you can use PATCH to replace this instruction with a 'HALT':

First make a copy of the SYS$LOADABLE:EXCEPTION.EXE into your local directory (if the offset is not 52D3, use the offset found in your EXCEPTION.EXE):

$ PATCH exception.exe
PATCH>repl/ins 52D3='BRB 52D3'
NEW> 'HALT'
NEW> exit
old: 000052D3: BRB 000052D3
new: 000052D3: HALT
new: 000052D4: NOP
PATCH>update

This will write the new (updated) EXCEPTION.EXE into your default directory. If you made an error and the old instruction is NOT 'BRB .', patch will complain and not modify the image.

BEFORE you activate this image, think of a strategy on how to remove the patched image from the system, if something goes wrong. Ideally, you could boot (B/10000000) from the OpenVMS VAX V7.1 operating system CD, mount your system disk and rename the 'bad' EXCEPTION.EXE. If you don't have a CDrom, you have to think of another way on how to remove a bad system execlet in case of some fatal error (BACK/IMA your disk and be prepared to restore it)...

Now you're ready to copy that new image to SYS$COMMON:[SYS$LDR]EXCEPTION.EXE;0 - then you need to rebot, to activate that new execlet. When you shut down the system next time, it will issue a HALT and drop to the 'chevron'-prompt '>>>'

Good luck,

Volker.

PS: These instructions are being provided 'as-is' and do explicitly exclude any kind of warranty. I have been doing this for at least one customer from V5.5-2 up to V7.3 - and it always worked !