Suddenly, had an interest in finding out the entropy of my laptop and ran time dd if=/dev/random of= bs=1M count=500.
For those of you who don’t know what /dev/random does, here’s a quote from wikipedia link.
In Unix-like operating systems, /dev/random is a special file that serves as a blocking pseudorandom number generator. It allows access to environmental noise collected from device drivers and other sources. Not all operating systems implement the same semantics for /dev/random.
And the results are in:
Date:17-Sep-2011. Torrent download going on. System uptime for about 7-8 hrs time dd if=/dev/random of=test_entropy bs=1M count=500 0+500 records in 0+500 records out 4025 bytes (4.0 kB) copied, 564.065 s, 0.0 kB/s real 9m24.855s user 0m0.005s sys 0m0.125s
Date: 19-Sep-2011 Just did some moving of files to the tune of close to 11-13GB. Torrent download going on. Here goes the results. anand@localhost:~ $ uptime 23:29:10 up 43 min, 2 users, load average: 0.61, 1.76, 2.49 anand@localhost:~ $ time dd if=/dev/random of=test_entropy bs=1M count=500 0+500 records in 0+500 records out 4413 bytes (4.4 kB) copied, 342.514 s, 0.0 kB/s real 5m42.538s user 0m0.007s sys 0m0.125s
Date: 20-Sep-2011. After a two hour movie. Here are the stats. 14:58:53 up 2:14, 2 users, load average: 6.62, 5.51, 5.31 0+500 records in 0 0 records out 4058 bytes (4.1 kB) copied, 367.482 s, 0.0 kB/s real 6m7.518s user 0m0.015s sys 0m0.108s
21-Sep-2011 Just moved 14GB data across two logical volumes. Wed Sep 21 13:42:25 IST 2011 13:42:25 up 3:59, 2 users, load average: 0.13, 0.60, 1.35 0+500 records in 0+500 records out 4296 bytes (4.3 kB) copied, 447.277 s, 0.0 kB/s real 7m27.311s user 0m0.006s sys 0m0.104s Uh..Think it's time to put this into a script+cron and store the data in a log file.
Uh..umm.. how do i change this to an entropy measure?? Anybody worked a formula yet or do i have to read up the manuals(and/or source code) and come up with my own?? Since /dev/random depends on the system interrupts(kb,mouse,HD access), i can get more datapoints, with trying it with some hd file transfers, playing some 3D game(openArena)/ simple game minesweeper/network download (torrent) etc…. Hmm. wonder if anyone has done this for their thesis, trying out various datapoints and fitting it into a curve. That would give an idea of the formula. Ofcourse, i have ignored the hardware differences, but it seems like a good thesis project for a Master’s graduate??.