为了搞学习内核编译，需要安装一些开发工具包，索性把光盘镜像设置成本地yum源，这样更快些！以下是一些基本步骤：
1、首先挂载光盘到/mnt/cd下，mount /dev/cdrom /mnt/cd，这个就不多说了；
2、 进入/etc/yum.repos.d/目录下，把原来的yum源备份，我给它重新命名了。
mv CentOS-Vault.repo CentOS-Vault.repo.bak
mv CentOS-Debuginfo.repo CentOS-Debuginfo.repo.bak
mv CentOS-Base.repo CentOS-Base.repo.bak
3、新建一个光盘源
vim CentOS-Media.repo
# CentOS-Media.repo
#
# This repo can be used with mounted DVD media, verify the mount point for
# CentOS-6. You can use this repo and yum to install items directly off the
# DVD ISO that we release.
#
# To use this repo, put in your DVD and use it with the other repos too:
# yum --enablerepo=c6-media [command]
#
# or for ONLY the media repo, do this:
#
# yum --disablerepo=\* --enablerepo=c6-media [command]
[c6-media]
name=CentOS-$releasever - Media
baseurl=file:///mnt/cd
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
保存退出
4、yum clean all(清除缓存)
5、yum makecache (建立新缓存)
