FAQ[redhat]から引用
Unlike Red Hat Enterprise Linux versions 2.1 and 3, there is no kernel-source package in the Red Hat Enterprise Linux 4 distribution.Release note[redhat]から引用
In order to eliminate the redundancy inherent in providing a separate package for the kernel source code when that source code already exists in the kernel's .src.rpm file, Red Hat Enterprise Linux 4 no longer includes the kernel-source package.
