Date: Sat, 3 May 2003 04:28:00 +0300 From: Giorgos Keramidas <keramida@ceid.upatras.gr> To: Joshua Oreman <oremanj@www.get-linux.org> Cc: questions@freebsd.org Subject: Re: Zeros and ones Message-ID: <20030503012800.GC1747@gothmog.gr> In-Reply-To: <20030503010727.GA28640@webserver.get-linux.org> References: <200305022353.h42NreOY018887@clunix.cl.msu.edu> <20030503000330.GA98398@falcon.midgard.homeip.net> <54693.192.85.47.1.1051923045.squirrel@new.host.name> <20030503010727.GA28640@webserver.get-linux.org>
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On 2003-05-02 18:07, Joshua Oreman <oremanj@www.get-linux.org> wrote: >On Fri, May 02, 2003 at 05:50:45PM -0700 or thereabouts, Kevin Stevens seemed to write: >>> On Fri, May 02, 2003 at 07:53:40PM -0400, Jerry McAllister wrote: >>>> Hi, >>>> >>>> This should be easy, but short of writing something specific to do it, >>>> I am not getting my head around how. >>>> >>>> It is easy and convenient to use /dev/zero to write out a number of >>>> zero bytes to somewhere - as in: >>>> >>>> But, I would like to write all ones - as in 0xff or maybe some >>>> other pattern - as if there was a /dev/one also. >> >> I absolutely can't believe it. At the exact time Jerry was struggling >> with this, I was working on *exactly* the same issue. Couldn't have >> phrased his question any better - I was actually looking in /dev for a >> "one" device! >> >> My way of resolving the problem, BTW, was to create a pure white bitmap in >> PhotoShop and trim it to the size I needed with "head". Different ways to >> skin the cat! ;) > > Yet another (theoretical) way to do it: > Create a 'rept' device driver in the kernel that uses ioctl() to set the > bytes to spew out. Base 'zero' on that. Could have a few uses... not :-) Not. We have tr(1) already. dd if=/dev/zero | tr '\000' '\xxx' >filename is the canonical way of creating ANY type of file that contains \xxx bytes, and it doesn't require special kernel hacking skills to work on any number of platforms :-)
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