dev目录介绍

  1 char	Memory devices
		  1 = /dev/mem		Physical memory access
		  2 = /dev/kmem		Kernel virtual memory access
		  3 = /dev/null		Null device 黑洞
		  4 = /dev/port		I/O port access
		  5 = /dev/zero		Null byte source 返回无限空字符
		  6 = /dev/core		OBSOLETE - replaced by /proc/kcore
		  7 = /dev/full		Returns ENOSPC on write 满的文件
		  8 = /dev/random	Nondeterministic random number gen.
		  9 = /dev/urandom	Faster, less secure random number gen.
		 10 = /dev/aio		Asynchronous I/O notification interface
		 11 = /dev/kmsg		Writes to this come out as printk's, reads 写消息
					export the buffered printk records.
		 12 = /dev/oldmem	Used by crashdump kernels to access
					the memory of the kernel that crashed.

  1 block	RAM disk
		  0 = /dev/ram0		First RAM disk
		  1 = /dev/ram1		Second RAM disk
		    ...

  2 char	Pseudo-TTY masters
		  0 = /dev/ptyp0	First PTY master
		  1 = /dev/ptyp1	Second PTY master
		    ...

  2 block	Floppy disks
		  0 = /dev/fd0		Controller 0, drive 0, autodetect
		  1 = /dev/fd1		Controller 0, drive 1, autodetect

  3 char	Pseudo-TTY slaves
		  0 = /dev/ttyp0	First PTY slave
		  1 = /dev/ttyp1	Second PTY slave
		    ...

...

原文见kernel/linux-3.10.y/Documentation/devices.txt