Fill up HD fastest way

[drunkenfist]

Hi,

I'm writing a Perl script that fills a HD with random data as fast as possible.

open(FILE,'>garbage.dat');
while(1) { print FILE rand() }

This is terribly slow, so I did some tweaking:

open(FILE,'>garbage.dat');
while(1) {
print FILE (rand() x 10000)
}

ha, that one is a lot faster!

Any faster way?

 

[Tassilo v. Parseval]

Also sprach (e-mail address removed):

I'm writing a Perl script that fills a HD with random data as fast as possible.

open(FILE,'>garbage.dat');
while(1) { print FILE rand() }

This is terribly slow, so I did some tweaking:

open(FILE,'>garbage.dat');
while(1) {
print FILE (rand() x 10000)
}

ha, that one is a lot faster!

Any faster way?

Yes.

system "cat /dev/urandom > garbage.dat";

Of course, this makes some gentle assumptions, like the existence of
/dev/urandom and cat(1).

Tassilo

 

[Sam Holden]

On 23 Oct 2003 09:26:29 GMT,

Hi,

I'm writing a Perl script that fills a HD with random data as fast as possible.

open(FILE,'>garbage.dat');
while(1) { print FILE rand() }

This is terribly slow, so I did some tweaking:

open(FILE,'>garbage.dat');
while(1) {
print FILE (rand() x 10000)
}

ha, that one is a lot faster!

And a lot less "random"...

 

[Sisyphus]

Hi,

I'm writing a Perl script that fills a HD with random data as fast as possible.

open(FILE,'>garbage.dat');
while(1) { print FILE rand() }

This is terribly slow, so I did some tweaking:

open(FILE,'>garbage.dat');
while(1) {
print FILE (rand() x 10000)
}

The same "random" number will be repeated 10000 times.
Not my idea of a HD full of "random" data

Cheers,
Rob

 

[Lambik69]

Any faster way?

how about something like:
#!/usr/bin/perl -w
use strict;

sub fisher_yates_shuffle {
my $array = shift;
my $i;
for ($i = @$array; --$i; ) {
my $j = int rand ($i+1);
next if $i == $j;
@$array[$i,$j] = @$array[$j,$i];
}
}

my @array = 1..1000000;
open(FILE,'>garbage.dat');
while(1) {
print FILE fisher_yates_shuffle (\@array);
}
close FILE;

 

[Eric J. Roode]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

how about something like:
#!/usr/bin/perl -w
use strict;

sub fisher_yates_shuffle {

Is that really faster?

- --
Eric
$_ = reverse sort $ /. r , qw p ekca lre uJ reh
ts p , map $ _. $ " , qw e p h tona e and print

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Version: PGPfreeware 7.0.3 for non-commercial use <http://www.pgp.com>

iQA/AwUBP5e6PWPeouIeTNHoEQI2SgCg3fMP0z3YuCAN1nSaDjUGaAOl8eMAnilo
u14RrlPjR0iMbwkDw7oirCey
=Mwor
-----END PGP SIGNATURE-----

 

[drunkenfist]

(e-mail address removed) ([email protected]) wrote on MMMDCCV
September MCMXCIII in <URL:~~
~~ Hi,
~~
~~ I'm writing a Perl script that fills a HD with random data as fast as possib
~~
~~ open(FILE,'>garbage.dat');

That opens a file, it won't fill a hard disk with random data - you will
still be left with a filesystem, and it won't overwrite existing files.

I'd do:

system "dd if=/dev/urandom of=/dev/rdsk/c1t6d2s2 bs=1024k"

(Assuming /dev/rdsk/c1t6d2s2 is the disk to be filled).

ehh, forgot to mention 'fill free space'. It should be portable as well.

 

[Roy Johnson]

How about
$fmt='%c'x100;
printf $fmt, map(int(rand(256)), 1..100) while 1;
or (probably better)
print pack('C100', map(int(rand(256)), 1..100)) while 1;

They're more random than just digits.

 

[Roy Johnson]

(e-mail address removed) (Roy Johnson) wrote in message A bit less random, a lot faster:

## Adjust numbers to taste.
my $preroll=pack('C17000', map(int(rand(256)), 1..17000));
print substr($preroll, rand(16000), 1000) while 1;