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From: Jon <jg@jguk.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: dd if=/dev/random of=data.bin bs=512 count=1
Date: Sat, 23 May 2009 20:12:59 +0100	[thread overview]
Message-ID: <4A184ABB.1070902@jguk.org> (raw)
In-Reply-To: <2f11576a0905170901x41e15f65sf10bb5ee36050d14@mail.gmail.com>

Hello KOSAKI,

Thank you for your reply.

KOSAKI Motohiro wrote:
>> Hello
>>
>> Issuing this command, I expected to get a file 4096 bytes in size.
>> Could someone let me know if I have missed something..? Or is there a
>> problem with using /dev/random this way?
>>
>> if I have a count=10 it hangs forever (several hours).
>>
>> Changing to use /dev/urandom and it generates the file ok.
> 
> you already have the answer. /dev/random might blocked, /dev/urandom doesn't.

Is this a "feature" of /dev/random ? ..it does not seem very useful to 
have it able to block for so long.

Please include my email address in replies,  as I'm not a member of this 
list.

Best regards, Jon

  reply	other threads:[~2009-05-23 19:13 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-17 15:22 dd if=/dev/random of=data.bin bs=512 count=1 Jon Grant
2009-05-17 16:01 ` KOSAKI Motohiro
2009-05-23 19:12   ` Jon [this message]
2009-05-23 19:20     ` Samuel Thibault
2009-05-23 19:38     ` Matt Mackall
2009-05-24  0:59     ` Bill Davidsen
2009-05-17 16:27 ` Bernd Eckenfels

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