svn commit: r265132 - in head: share/man/man4 sys/dev/null

Warner Losh imp at
Wed Apr 30 19:54:19 UTC 2014

On Apr 30, 2014, at 11:13 AM, Ian Lepore <ian at> wrote:

> On Wed, 2014-04-30 at 17:22 +0100, Steven Hartland wrote:
>> ----- Original Message ----- 
>> From: "Ian Lepore" <ian at>
>> To: "Eitan Adler" <eadler at>
>> Cc: <src-committers at>; <svn-src-all at>; <svn-src-head at>
>> Sent: Wednesday, April 30, 2014 3:48 PM
>> Subject: Re: svn commit: r265132 - in head: share/man/man4 sys/dev/null
>>> On Wed, 2014-04-30 at 06:20 +0000, Eitan Adler wrote:
>>>> Author: eadler
>>>> Date: Wed Apr 30 06:20:48 2014
>>>> New Revision: 265132
>>>> URL:
>>>> Log:
>>>>  Add a /dev/full device.
>>>>  /dev/full is similar to /dev/zero except it always returns
>>>>  ENOSPC when you attempt to write to it.
>>> For some reason this reminded me of something I've been wanting for a
>>> while but never get around to writing... /dev/ones, it's just
>>> like /dev/zero except it returns 0xff bytes.  Useful for dd'ing to wipe
>>> out flash-based media.
>> Surely for that you want camcontrol security ...?
>>    Regards
>>    Steve
> I have no idea what that is, but given that it has "security" in the
> name, it's almost certainly NOT what I want in any way shape or form.
> Shocking as it may be, some people are just not obsessed with security,
> for good reason.  It just isn't a consideration in any way in my day to
> day activities.  
> When I want to make an sdcard, or some portion thereof, look
> empty/virgin/new-from-factory for testing on an embedded system, that
> has nothing to do with security, and everything to do with just exactly
> what I asked for:  something that writes all-ones-bits.
> Besides, cam and sdcards don't play in the same sandboxes.

You likely want some variation of the SATA secure erase command, which despite having the name ‘secure’ in it really is a ‘erase all contents of this drive and reinitialize to factory defaults’.


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