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
...