Block Device Files: Block device files talks to devices block by block [1 block at a time (1 block = 512 bytes to 32KB)]. Examples: – USB disk, CDROM, Hard Disk # ls /dev/sd* brwrw— 1 root root 8, 0 Mar 15 2009 sda brwrw— 1 root root 8, 1 Mar 15 2009 sda1 brwrw— 1 root root 8, 2 Mar 15 2009 sda2 brwrw— 1 root root 8, 3 Mar 15 2009 sda3 brwrw— 1 root root 8, 4 Mar 15 2009 sda4 brwrw— 1 root root 8, 16 Mar 15 2009 sdb Character Device Files: Character device files talk to devices character by character. Examples: – Virtual terminals, terminals, serial modems, random numbers #ls /dev/tty* crwrw— 1 root root 4, 64 Mar 15 2009 ttyS0 crwrw— 1 root root 4, 65 Mar 15 2009 ttyS1 crwrw— 1 root root 4, 66 Mar 15 2009 ttyS2 crwrw— 1 root root 4, 67 Mar 15 2009 ttyS3