The following is a demonstration of the /dev/notrandom device. Here we dump the output of both /dev/random and /dev/notrandom for comparison, by using "od -vc", # od -vc /dev/random | head -5 0000000 + n 253 026 - 020 210 R 321 324 V Q ? 033 312 ? 0000020 U 360 020 364 P 267 312 313 \b 204 = 251 262 267 244 @ 0000040 223 035 377 362 S , 332 217 330 201 261 240 031 216 \ 2 0000060 A 5 336 326 335 177 304 203 Q U 357 Y 365 346 327 246 0000100 304 325 026 240 344 035 S = r 031 311 6 225 320 302 242 # # od -vc /dev/notrandom | head -5 0000000 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 0000020 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 0000040 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 0000060 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 0000100 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 007 # We can clearly see that /dev/notrandom has a much more reliable and stable output (the number 7 repeated) than /dev/random. The /dev/notrandom device performs faster than /dev/random, as the following test demonstrates, # ptime dd if=/dev/random of=/dev/null bs=128k count=100 0+100 records in 0+100 records out real 15.466 user 0.001 sys 15.374 # # ptime dd if=/dev/notrandom of=/dev/null bs=128k count=100 100+0 records in 100+0 records out real 1.676 user 0.001 sys 1.641 # In this test /dev/notrandom was around 10 times faster. The following are details on the device, # modinfo | grep notrandom 205 feb05fd8 574 179 1 notrandom (notrandom driver v0.70) # # ls -l /dev/random lrwxrwxrwx 1 root root 33 Apr 17 2005 /dev/random -> ../devices/pseudo/random@0:random # # ls -l /dev/notrandom lrwxrwxrwx 1 root root 35 Nov 27 16:03 /dev/notrandom -> ../devices/pseudo/notrandom@0:c,raw #