From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754306AbZEQPWh (ORCPT ); Sun, 17 May 2009 11:22:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752853AbZEQPW1 (ORCPT ); Sun, 17 May 2009 11:22:27 -0400 Received: from mail-fx0-f158.google.com ([209.85.220.158]:46414 "EHLO mail-fx0-f158.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752786AbZEQPW0 (ORCPT ); Sun, 17 May 2009 11:22:26 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:date:x-google-sender-auth:message-id:subject :from:to:content-type:content-transfer-encoding; b=S4JFsJOJgtLVH/PwhxU3BgWBuARt9DhKGW2kvfrrEj+GcAUQeKaZqfDlxiz+U2wLEv ohq1KdDb/qVtqDUIA98x45GXWDmDBhsQgNWOtFqQpImg6tsr5u9FSsY1KJfj3ptWw71J vPoP3iv1PL1BubP4YCuxRXVcd+dZwP4JPZyck= MIME-Version: 1.0 Date: Sun, 17 May 2009 15:22:26 +0000 X-Google-Sender-Auth: 1c8ef74b33074b4a Message-ID: <19ac3f7a0905170822q28255239nea01b56d52e3ddf8@mail.gmail.com> Subject: dd if=/dev/random of=data.bin bs=512 count=1 From: Jon Grant To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Please include my email address in replies, as I'm not a member of this list. Best regards, Jon $ dd if=/dev/random of=data.bin bs=512 count=1 0+1 records in 0+1 records out 8 bytes (8 B) copied, 4.47366 s, 0.0 kB/s $ dd --version dd (coreutils) 6.10 $ uname -a Linux ubuntu 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009 i686 GNU/Linux