Using the boot and dev Directories

Using the /boot and /dev Directories

The /boot directory contains a compressed version of the Linux kernel that loads at boot (earlier versions of the startup script delivered a message that the kernel was "exploding," which undoubtedly unnerved more than a few novices in those days). When you rebuild or install a new kernel, the new kernel and related files go first into this directory (see Chapter 24, "Kernel and Module Management," for more information on updating your kernel).

Linux device files are located in the /dev directory. As noted earlier, nearly everything in Linux is represented as a file. No further proof is needed than a peek into this directory. There you will find about 7,500 files representing devices that are or may some day be attached (or not) to your system. The more commonly used devices include the following:

• IDE and SCSI hard drives, represented as hda and sda, respectively.

• CD-ROM, CD-R, and CD-RW drives (and their DVD counterparts), some of which are IDE; others are viewed by the system as SCSI.

• Serial ports, marked tty.

• Pointing devices, such as /dev/input/mouse.

• Universal Serial Bus (USB) devices, in the dev/usb directory.

• Printers, marked lp.

If you're running short of disk space, you might think cleaning out some of these files would help you. Closer inspection reveals that they are all 0byte files. Leave them alone.