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In article <01GRDFI4HY2A8WVZBS@MONMOUTH-etdl1.Army.MIL>, Brian J. Schenkenberger, VAXman writes:
> I've never done this but... I can offer you a quick method to change
> the value.
> 
> The value for WSMAX is stored at the symbolic address SGN$GL_MAXWSCNT.
> You can change this value WHILE THE SYSTEM IS RUNNING with DELTA.  How?
> Lookup the address of SGN$GL_MAXWSCNT in SYS.MAP.  Then, enter DELTA.
> 
> $ RUN SYS$SHARE:DELTA
> 1:m <cr>
> 00000001 <cr>
> 00010001:<address of SGN$GL_MAXWSCNT>/<return-curr-value> <your-new-value>
> EXIT                                                       (hex of course)
> $
> 
>>Caveats ? :-)
> 
> This above will change the value.  Its implications if you increase it
> above the current limits? I know not!  I just LOWERed my system's WSMAX
> by 16 with the above and have had no problems.
> 
You should have no problems if you LOWER the value of WSMAX this way, but you
WILL have some if you RAISE it.  WSMAX is a parameter that is used to calculate
the size of a balance set slot (which is done early in the boot process).  If
you raise the value of WSMAX beyond the value it had at system startup the
system will overwrite the head of one balance slot when it is trying to use the
tail of the previous one, thus corrupting the PHD of a resident process, which
will shortly cause a crash or hang of the entire system.


-- 
Mike Jacobi
NAVSSES VAXCluster system manager
System@Eagle.Navsses.Navy.Mil
System@Condor.Navsses.Navy.Mil

Disclaimer - I speak for myself.  No-one else.

In article <01GRDFI4HY2A8WVZBS@MONMOUTH-etdl1.Army.MIL>, "Brian J. Schenkenberger, VAXman" writes:
>>Under VMS 5.5-2 the maximum value for wsmax is 400000 pages.
>>[...]
>>he can't have more than 400000 pages im memory.
>>
>>I'm sure some higher Version of VMS will raise this limit eventually,
>>but 400000 seems a rather arbitrary value, so i guess this could be
>>increased somehow.
>>
>>Has anybody done this ?
>>Any ideas / pointers how to do it ?
>
> I've never done this but... I can offer you a quick method to change
> the value.
>
> The value for WSMAX is stored at the symbolic address SGN$GL_MAXWSCNT.
> You can change this value WHILE THE SYSTEM IS RUNNING with DELTA.  How?
> Lookup the address of SGN$GL_MAXWSCNT in SYS.MAP.  Then, enter DELTA.
>
> $ RUN SYS$SHARE:DELTA
> 1:m <cr>
> 00000001 <cr>
> 00010001:<address of SGN$GL_MAXWSCNT>/<return-curr-value> <your-new-value>
> EXIT                                                       (hex of course)
> $
>
>>Caveats ? :-)
>
> This above will change the value.  Its implications if you increase it
> above the current limits? I know not!  I just LOWERed my system's WSMAX
> by 16 with the above and have had no problems.
>
> If you have a system you can crash... try it out and let us know.

Certainly an interesting technique, but I'm real sure that making things bigger
this way is certainly going to crash the system.  Off the top of my head I'm
not sure where this number is used to allocate parts of several significant
process data structures.  If this number were variable it would be a dynamic
sysgen parameter.

A possible approach to running with a larger value is:

Boot the system conversationally:

	>>> B/R5:1


Now disable Value range checking and select a larger value:

	SYSBOOT> DISABLE CHECKS
	SYSBOOT> SET WSMAX 524287
	SYSBOOT> EXIT

I did this once to exceed the maximum numbers for SRPCOUNT and SRPCOUNTV.

Note: I've chosen the above number (524287) since it definately is
representable in the same number of bits as the current max of 400000.
Going to larger values may affect other data structures which I can't
remember offhand.

--
Mark Pizzolato - INFO COMM Computer Consulting, Redwood City, Ca
PHONE:	(415)369-9366	UUCP:  decwrl!infopiz!mark or uunet!lupine!infopiz!mark
DOMAIN:	mark@infocomm.com

In article <01GRDFI4HY2A8WVZBS@MONMOUTH-etdl1.Army.MIL>, "Brian J. Schenkenberger, VAXman" writes...
>>Under VMS 5.5-2 the maximum value for wsmax is 400000 pages.
>>[...]
>>he can't have more than 400000 pages im memory.
>>
>>I'm sure some higher Version of VMS will raise this limit eventually,
>>but 400000 seems a rather arbitrary value, so i guess this could be
>>increased somehow.
>>
>>Has anybody done this ?
>>Any ideas / pointers how to do it ?
> 
>I've never done this but... I can offer you a quick method to change
>the value.
> 
>The value for WSMAX is stored at the symbolic address SGN$GL_MAXWSCNT.
>You can change this value WHILE THE SYSTEM IS RUNNING with DELTA.  How?
>Lookup the address of SGN$GL_MAXWSCNT in SYS.MAP.  Then, enter DELTA.
> 
>$ RUN SYS$SHARE:DELTA
>1:m <cr>
>00000001 <cr>
>00010001:<address of SGN$GL_MAXWSCNT>/<return-curr-value> <your-new-value>
>EXIT                                                       (hex of course)
>$
> 
>>Caveats ? :-)
> 
>This above will change the value.  Its implications if you increase it
>above the current limits? I know not!  I just LOWERed my system's WSMAX
>by 16 with the above and have had no problems.
> 
>If you have a system you can crash... try it out and let us know.
>BJS-

Somehow I expect that it WOULD crash.  There's a reason why WSMAX isn't
dynamic -- I believe that this value is used to set up some static-sized
data structures for each balance set slot, and that if you increase WSMAX
willy-nilly in a running system, you're likely to scrawl all over some
other process data structure.  You'd probably be better off trying this
little bit of POKEing at boot time, using XDELTA to change the setting
after the parameters have been read but before the balance set slot data
structures have been set up.

Just my $0.02....

John Francini
PATHWORKS for VMS project leader
Digital
francini@narfvx.enet.dec.com