Solution to MySQL failure to start

[root@www ~]$ service mysql start 
Starting MySQL..^[[A.................................................................................................. ERROR! The server quit without updating PID file (/disk/mysql/www.pid).
[root@www ~]$ service mysql stop 
 ERROR! MySQL server PID file could not be found!
[root@www ~]$ service mysql stop 
 ERROR! MySQL server PID file could not be found!
[root@www ~]$ service mysql start 
Starting MySQL..................
It's still the same as before, so I have to press Ctrl+C to cancel it.
[root@www ~]$
 

120608 09:56:17 mysqld_safe Starting mysqld daemon with databases from /disk/mysql
120608 9:56:17 [Note] Plugin 'FEDERATED' is disabled.
120608 9:56:17 InnoDB: The InnoDB memory heap is disabled
120608 9:56:17 InnoDB: Mutexes and rw_locks use InnoDB's own implementation
120608 9:56:17 InnoDB: Compressed tables use zlib 1.2.3
120608 9:56:17 InnoDB: Using Linux native AIO
120608 9:56:17 InnoDB: Initializing buffer pool, size = 128.0M
120608 9:56:17 InnoDB: Completed initialization of buffer pool
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
120608 9:56:17 InnoDB: Retrying to lock the first data file
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
InnoDB: Unable to lock ./ibdata1, error: 11
...

[root@www ~]$ ps -ef|grep mysql 
root 4769 1 0 Jun06 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/disk/mysql --pid-file=/disk/mysql/localhost.pid
mysql 4874 4769 0 Jun06 ? 00:04:04 /usr/sbin/mysqld --basedir=/usr --datadir=/disk/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/disk/mysql/localhost.err --pid-file=/disk/mysql/localhost.pid --socket=/disk/mysql/mysql.sock
root 17947 1 0 09:56 pts/1 00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/disk/mysql --pid-file=/disk/mysql/www.pid
mysql 18052 17947 0 09:56 pts/1 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/disk/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/disk/mysql/www.err --pid-file=/disk/mysql/www.pid --socket=/disk/mysql/mysql.sock
root 18099 17514 0 09:56 pts/1 00:00:00 grep mysql
[root@www ~]$ killall mysqld 
[root@www ~]$ killall mysqld 
[root@www ~]$ ps -ef|grep mysql 
root 18116 17514 0 09:57 pts/1 00:00:00 grep mysql
[root@www ~]$

[root@www ~]$ service mysql start 
Starting MySQL. SUCCESS! 
[root@www ~]$ 
[root@www ~]$ 
[root@www ~]$ 
[root@www ~]$ 
[root@www ~]$ service mysql start 
Starting MySQL SUCCESS! 
[root@www ~]$
 

[root@www ~]$ perror 11 
OS error code 11: Resource temporarily unavailable
[root@www ~]$ 
[root@www ~]$