Hello Russell;
/dev/random uses the following external interfaces for gathering
environmental noise (input).
keyboard
mouse
interrupt
block devices.
On the ARM system that we are developing we have very few block devices, no
keyboard and no mouse. Therefore I get very little output from /dev/random.
Little input = little output.
Best Regards,
George
George France, france@crl.dec.com
Cambridge Research Laboratory, Compaq Computer Corporation
One Kendall Square, Building 700 MS: CRL
Cambridge, MA 02139 USA
-----Original Message-----
From: Russell King [mailto:rmk@arm.linux.org.uk]
Sent: Tuesday, February 01, 2000 6:18 PM
To: linux-kernel@vger.rutgers.edu
Subject: /dev/random oddness
Hi,
I've just had a report that I've confirmed that /dev/random on ARM doesn't
behave the same as /dev/random on x86.
I've confirmed this by comparing a NetWinder with an IBM thinkpad. Both
these
have PS/2 mice. The NetWinder is running 2.3.41, which uses the standard
random.c and pc_keyb.c sources. The thinkpad is running untouched 2.2.12 at
the moment.
On the thinkpad, doing an 'od -t x1 -Ax /dev/random' and moving the mouse in
a console results in a lot of bytes being generated from the device.
However,
on a NetWinder, it results in very few, less than 1/10th of what the x86
machine produces.
I have also compared it with other ARM architectures (on 2.2.14) use the
busmice code (which got added to 2.3 iirc) to add randomness, and that
behaves
in the same manner as the NetWinder.
Does anyone have any clues what might be causing this odd behaviour? I
haven't
scanned over random.c in any great depth yet.
_____
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