My laptop entropy

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.[1] 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 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??.


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