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Old 12-01-2003, 12:19 AM   #1
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Registered: Apr 2003
Location: nottingham england
Distribution: Gentoo
Posts: 2,672

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why did cat /dev/urandom send my printer insane ?

for testing purposes i needed a large file,
so i thought i could use
cat /dev/urandom > bigFile
to generate a big random file.

out of curiocity i typed cat /dev/urandom to see what came out...

as expected the screen filled with random characters, then after a few seconds...
what should have been standard console output caused my printer to wake up, and print half a page of random characters...

why ?

and if this standard output can "get lost" and end up in the printer..
(my sound output made a slight noise too)
should i be worried that it could have found its way also to my ppp0 and damaged my downloads ???
im using redhat 9.
Old 12-01-2003, 03:41 AM   #2
Registered: Nov 2002
Location: England
Distribution: Ubuntu 9.04
Posts: 631

Rep: Reputation: 30
I don't know the answer, this is just an idea.

When you do a cat from /dev/urandom you are getting a reasonably random stream of 0s and 1s. On your screen these are translated into ASCII characters which should be random.

It may be the case than somewhere in the stream of characters you hit a sequence of binary numbers which translated into a carriage return, followed by "lp" or something similar, which the OS then interpreted as if someone had told the computer to start printing from STDIN.


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