Oracle: Why is DBW terminating my Instance? I was performing routine administrative tasks on an Oracle instance and I was not able to connect to it. 

I proceeded to do as follows to reach a diagnosis:


I checked for Oracle processes in memory and saw that the instance was down.
I tried to startup the instance but it never responded to the startup command. It simply stalled. No output or feedback, no matter how long I wait. Only a kill -9 can get me out of it.
I reviewed the alert log and the last message was 3 days ago:


"DBW0: terminating instance due to error 472
Instance terminated by DBW0, pid = 14952"




Questions


What can cause BDW to terminate an instance?
Why I don't get any feedback, whether in the sqlplus console or the alert log when I try to startup the instance. 


When I ran strace, I got this:

ERROR: unable to open /dev/log.

I'm running Oracle on SunOS 5.8 Generic_117350-08 sun4u sparc SUNW,Sun-Fire. The RDBMS version is 9.2.0.8.0

EDIT:

I followed advice from both @balazs-papp and @jsapkota about running truss:

When I run truss on the sqlplus the I try to startup the instance, I get this output:

read(0, " s t a r t u p\n", 1024)               = 8
write(9, "\0 U\0\006\0\0\0\0\0038A".., 85)      = 85
read(10, 0x10029A536, 2064)     (sleeping...)
signotifywait()                 (sleeping...)
lwp_cond_wait(0xFFFFFFFF7D62B058, 0xFFFFFFFF7D62B068, 0xFFFFFFFF7D621C80) (sleeping...)
lwp_cond_wait(0xFFFFFFFF7D62B058, 0xFFFFFFFF7D62B068, 0xFFFFFFFF7D621C80) (sleeping...)
door_return(0x00000000, 0, 0x00000000, 0) (sleeping...)



How can I interpret this output? It's totally cryptic to me.
I exected startup nomount with explicit pfile paremeter and it works. 

I have the init &lt; SID >.ora in the $ORACLE_HOME/dbs/  directory, and always was working.