multi-named instance exist?

[dev_null at zoho.com]

 > If named is invoked successfully on startup, then the contents of the 
 > PID file will be overwritten with the new PID value. 
 >  
 > If named *isn't* invoked successfully on startup, then that's a separate 
 > error condition that should be detected and dealt with, within the whole 
 > startup subsystem. 
 >  
 > The problems with using "ps" to find the named process include: 
 > -- you can get false matches if you don't tailor your string matching 
 > _just_right_, 
 > -- unexpectedly "missed" matches if the command-line arguments change, 
 > even a little bit (e.g. if someone bypasses the wrapper script on an 
 > emergency basis to start the process manually, with the arguments given 
 > perhaps in a different order), and 
 > -- since "ps" operates on a constantly-changing data source, it can 
 > "miss" legitimate processes in the process table. I've seen that happen 
 > many many times with "ps" on Solaris, not sure if Linux or other flavors 
 > of Unix have some sort of concurrency-control mechanism to prevent that 
 > phenomenon. 
 >  
 

I agree all your opitions on ps's drawbacks.
what I said is, kill -0 $PID will return true even the process who owns $PID isn't named.

for example, named.pid wasn't removed after a system shutdown, the value in it is 1234.
after system startup, another process is launched and owns that process id of 1234.

so, this start script will not work:

if kill -0 $PID; then
      :
else
      /usr/local/sbin/named -u nobody
fi

Thanks.