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Date: Fri, 26 Dec 2008 05:43:31 +0300
From: Solar Designer <>
Subject: Re: large pot and --show problem

On Fri, Dec 26, 2008 at 01:54:44AM +0000, Ruben Lara wrote:
> My password files and my pot are majority formed by DES Hashes.
> I use JtR version without any patches, downloaded from

Oh, then my guess does not apply.  You may still try commenting out that
loop in loader.c, but it will probably not make that much of a difference.

You mentioned that your pot file is 400 MB.  How large is the password
file that is slow to --show?  And just how much time does --show on it
take to complete?

> My machine brute forcer is old one, 1,7 processor and only 512 RAM memory with Debian Unstable, maybe, slow machine is the problem.

512 MB RAM does sound a bit low for dealing with a 400 MB pot file, but
that is not necessarily the main problem - please see below.

> john --show put my processor at 0.7 %CPU and 67 %MEM.

That's weird.  If the process consumes very little CPU as you say (below 1%)
and presumably not all memory it could get, then what does it spend most
of its time on?  Can you perhaps copy & paste the first few lines of "top"
output while the process is running - those lines that show user vs.
system CPU time percentages, as well as memory and swap usage info?
Also include the line for the "john" process.

Then, can you please run "/sbin/hdparm -t" on any relevant hard drive
devices (where your files reside, where the swap partition resides) -
and post the output?  If any IDE hard drives are involved, then please
also do "/sbin/hdparm -d /dev/hda" and the like.  One guess is that you
might not have DMA on an IDE drive enabled, and indeed reading 400 MB
without DMA will take ages (well, it may take 2 minutes).

> >
> Well, i tried to follow you, i looked for DES_fmt.c file in jtr source,

Oh, you did not need to; that comment applied to *_fmt.c files coming
from patches.  All *_fmt.c files included in the official JtR don't have
the problem.

> and try to comment block, previous post say, but i couldn't find that loop anywhere...

That loop is in loader.c.

I hope this helps, and I wish a Merry Christmas to everybody on the list.


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