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Date:      16 May 2006 17:36:10 -0000
From:      Larry Baird <lab@gta.com>
To:        freebsd-small@freebsd.org
Cc:        Robert Krten <root@parse.com>
Subject:   Re: Smallest/fastest x86 6.0
Message-ID:  <20060516173610.59276.qmail@gta.com>
In-Reply-To: <200605161629.k4GGTPfN065519@amd64.ott.parse.com>

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In article <200605161629.k4GGTPfN065519@amd64.ott.parse.com> you wrote:
> Can anyone give me a ballpark idea on what size the smallest
> image would be, and how fast it could boot, for a 6.0 (or 6.1)
> bare bones x86 kernel with a serial driver, filesystem (suitable
> for a 32MB flash device; even a DOS filesystem is fine) and
> enough guts to load a "hello world"-sized C program, on a 500
> MHz PIII class of machine?  I'm hoping for something along the
> lines of 2-4MB and <10s ...
> 
> I know it's kind of a vague question, but I'm trying to
> get a handle on just how "embeddable" FreeBSD is.  PHK gave
> a talk at BSDCan 2006 last weekend, and I believe the number
> he guessed at was around 9MB but that was using nanoBSD; he
> then went on to say that picoBSD would be the way to go, but
> that perhaps there needed to be some more development on that
> front...
> 
> Comments?
I have created very small embedded FreeBSD using as small as 1.6MB.
For this I replaced init with my own init and basically kernel, new
init and a few services.  I agree with PKH that picoBSD is a good
place to start.  As far as time to boot, the limiting factor is often
the BIOS.  Just checked on an embedded development box I have and saw
a boot time of ten seconds after BIOS finished.  This box is really just
a standard PC with a standard BIOS.  The BIOS takes about 15 seconds to
complete.  On "real embedded" hardware I am seeing a BIOS time of about 
4 seconds.  

Hope this helps.

Larry

-- 
------------------------------------------------------------------------
Larry Baird                        | http://www.gta.com
Global Technology Associates, Inc. | Orlando, FL
Email: lab@gta.com                 | TEL 407-380-0220, FAX 407-380-6080



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