Re: /dev/random
On Mon, Aug 4, 2014 at 7:52 PM, Joel Rees <joel.rees@gmail.com> wrote:
> On Sat, Aug 2, 2014 at 11:01 AM, Joel Rees <joel.rees@gmail.com> wrote:
>> [...]
>>
>> Now, the random typing is not necessary.
>
> Well, it's not as rosy as I thought, for /dev/random:
>
> ------------------------
> duty@deb:~/math_work/sf/rollcalld$ time dd bs=128 count=16
> if=/dev/random iflag=fullblock of=randump2
> 16+0 レコード入力
> 16+0 レコード出力
> 2048 バイト (2.0 kB) コピーされました、 107.939 秒、 0.0 kB/秒
>
> real 1m47.945s
> user 0m0.004s
> sys 0m0.012s
> duty@deb:~/math_work/sf/rollcalld$ time dd bs=128 count=16
> if=/dev/urandom iflag=fullblock of=urandump2
> 16+0 レコード入力
> 16+0 レコード出力
> 2048 バイト (2.0 kB) コピーされました、 0.000850541 秒、 2.4 MB/秒
>
> real 0m0.048s
> user 0m0.004s
> sys 0m0.004s
> ------------------------
>
> I want to take a 2 MB dump from both and run some statistical stuff on
> them. Which means I'm going to have to start the one for urandom in
> the morning one day when I'm going to be doing something else with a
> lot of typing and other entropy improving stuff and see how long it
> takes to dump 16 kilobytes, and then try 64 kilobytes, and so forth
> until I have an idea how long it will take.
--------------------------
duty@deb:~/math_work/sf/rollcalld$ time dd bs=128 count=128
if=/dev/urandom iflag=fullblock of=urandump2
128+0 レコード入力
128+0 レコード出力
16384 バイト (16 kB) コピーされました、 0.00482425 秒、 3.4 MB/秒
real 0m0.011s
user 0m0.000s
sys 0m0.004s
duty@deb:~/math_work/sf/rollcalld$ time dd bs=128 count=128
if=/dev/random iflag=fullblock of=randump2
128+0 レコード入力
128+0 レコード出力
16384 バイト (16 kB) コピーされました、 946.389 秒、 0.0 kB/秒
real 15m46.570s
user 0m0.008s
sys 0m0.120s
--------------------------
Reading e-mail and posting to one of my blogs while I dumped /dev/random .
16 minutes for 16K, looks like 64K will be an hour and a half or so.
16K is enough for some initial analysis. Need to allocate some time for it.
--
Joel Rees
Be careful where you see conspiracy.
Look first in your own heart.
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