Figuring out which man page you need, however, isn't always straightforward. If you are unsure what a particular device is used for, you can usually figure out the meaning of the base name. For example, hd for IDE hard disks, sd for SCSI hard disks, fd for floppy drives, and so forth. Often there is a general man page for that type of device, so man sd will call up the page for SCSI type hard drives. Alternatively, you can use the -k option on man to search for a particular keyword.
Man pages are useful, when they exist.
Unfortunately, not all devices have an associated man page. There, you will find a file called devices.txt, which is a reasonably comprehensive list of the major numbers. Often this file will also list the minor numbers for each device, or at least give an explanation of the related minor numbering scheme. James Mohr is the author of books on Linux, SCO Unix, Web site administration, and Unix-Windows integration.