With the introduction of modularization in the Linux kernel there have been some significant changes in building customized kernels. In the past you were required to compile support into your kernel if you wanted to access a particular hardware or filesystem component. For some hardware configurations the size of the kernel could quickly reach a critical level. To require ready support for items that were only occasionally used was an inefficient use of system resources. With the new capabilities of the kernel, if there are certain hardware components or filesystems that are used infrequently modules can be loaded on demand. For information on handling kernel modules see section 8.6.