块设备

“b” 指明该设备节点是块设备 (ls -l)
brw-rw--- 1 root disk 3, 1 Feb 23 2004 hda1
brw-rw--- 1 jdoe floppy 2, 0 Feb 23 2004 fd0
brw-rw--- 1 root disk 7, 0 Feb 23 2004 loop0
brw-rw--- 1 root disk 1, 1 Feb 23 2004 ram1
brw------- 1 root root 8, 1 Feb 23 2004 sda1

典型块设备

磁盘, ramdisk,SD卡,U盘等等