CentOS5.4からCentOS5.5にyum update.
# cat /etc/redhat-release
CentOS release 5.4 (Final)
# cat /etc/redhat-release
CentOS release 5.5 (Final)
kernel-2.6.18-194.el5
httpd-2.2.3-43.el5.centos
mysql-5.0.77-4.el5_4.2
samba-3.0.33-3.28.el5
perl-5.8.8-27.el5
php-5.1.6-27.el5