Messages in this thread | | | Date | Sat, 26 Dec 1998 21:59:30 +0100 | Subject | Re: /dev/one - why not /dev/repeat? | From | Durandal@t-online ... |
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> From: Horst von Brand <vonbrand@sleipnir.valparaiso.cl> > Date: Fri, 25 Dec 1998 21:40:51 -0400 > Subject: Re: /dev/one - why not /dev/repeat?
> As I said before, there is _nothing_ in /dev/random that the application > itself can't do, so this is at the very least a waste of a system call. Not > exactly efficient. You would loose the entropy pool feature; at least you wouldn't have access to good random sources such as interrupts.
> > One use would be for low level file (device) acesss as mentioned in the > > 'wipe' thread. Compounding two pipes, to strip 4,000,000,000 line feeds, > > from using the 'yes' | 'tr' is slow and sloppy. It also assumes both > > commands are actually available. > > They are available on every Unixy system I know. If not, you can cobble > something up using the shell (a while loop + echo). Or you do have some > compiler at hand, so you can write a C (or whatever) proggie, using > random(3) as needed. I don't know where one would need random to implement a /dev/repeat. If you are refering to /dev/random, random(3) doesn't give you random numbers that are nearly the same quality as the /dev/random version (that's why they call it pseudo-random).
<man 3 random> The random() function uses a non-linear additive feedback random number generator employing a default table of size 31 long integers to return successive pseudo-random num- bers in the range from 0 to RAND_MAX. </man 3 random>
RFC 1750 is enlightening. Especially "6.2 Non-Hardware Sources of Randomness" as it deals with the randomness provided by standard hardware.
1750 Randomness Recommendations for Security. D. Eastlake, 3rd, S. Crocker & J. Schiller. December 1994.
Regards,
Georg
-- Georg Wilckens <durandal@t-online.de> http://home.t-online.de/home/durandal Quantum mechanics - the dream stuff is made of
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