Like many other smart phones, the Samsung Galaxy S9000 has the annoying habit of playing a very loud sound on startup -- and another one on shutdown. It's hard to imagine anyone actually preferring this behaviour to what would be the most sensible: Quietness during either process.

To make the phone shut up, you can do this (provided you have rooted the phone already; note that we've go no tab-completion on the phone, so better cd to the respective directory before moving the files):

1. ssh to the phone
2. Remount the system partition as read-write:
   

   # mount -o remount,rw /dev/block/stl9 /system
   

3. Move the startup sound away:
   

   # cd /system/etc
   # mv PowerOn.wav PowerOn.wav.orig
   

4. Move the shutdown sound away:
   

   # cd ../media/audio/ui
   # mv shutdown.ogg shutdown.ogg.orig
   

5. Reboot.

You should not hear the sounds anymore.