From: Spiro Trikaliotis (ml-cbmhackers_at_trikaliotis.net)
Date: 2006-07-16 14:00:32
Hello silverdr,
thank you for your answer.
* On Sun, Jul 16, 2006 at 12:08:37PM +0200 silverdr wrote:
>
> On 2006-07-09, at 10:27, Spiro Trikaliotis wrote:
> >What do you think? Is there a better approach then the one proposed
> >there?
>
> Since nobody answered this - it seems "no" ;-)
Yes, I believe this, too.
I discussed with another collegue and I think I might have a good
variant of this now. I will need to implement it to verify.
> I see no way to distinguish the position of the device on the bus
> unless we were able to measure over-the-wire signal propagation
> latency...
yes, this is true. Anyway, even a "works in most cases" solution might
work here, too.
> >Additionally, from where could I get a true random number in the
> >floppy?
>
> Hm, a "true random" you rather get nowhere but even a kind of quasi-
> random may be tough to get from the floppy. Thinking aloud... maybe
> feeding some timers with off-the-(magnetic)head readout?
I thought about some things:
1. The rpm variance of the disc might be a good pointer; if there is a
disc inside the drive, I can estimate that value.
2. If there is no disc, the drive will spin up and spin down. In this
time, the timers of different drives will drift significantly away
from each other, thus, even without an attached disc, the timers
should be "good enough" not to give the same values.
With these two facts, I think I can determine a "good enough" seed for a
PRNG, which will help me here.
When I find some time, I will implement it and try it out.
Regards,
Spiro.
--
Spiro R. Trikaliotis
http://www.trikaliotis.net/
http://opencbm.sf.net/
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