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List:       openbsd-arm
Subject:    Re: A simple [question] about the openbsd kernel
From:       Ian Darwin <ian () darwinsys ! com>
Date:       2007-09-16 15:40:20
Message-ID: 46ED4E64.3000108 () darwinsys ! com
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PowerMan wrote:

>>            I am an embedded system engineer writing device drivers
>> for arm-linux based system and I intend to learn OS kernel, but
>>  I find that the 2.6 linux kernel is too large and complex, so I intend to
>> change to
>> others.
>>            How about openbsd kernel?  How many lines does it have?
>> Or how many mega bytes does it have ? Is it less complex to learn?
>>            I arm only familiar with the arm architecture.

You will have to do the comparison yourself. We think our kernel is 
pretty good, but your kernel developers (I'm not one) are generally too 
busy improving it to answer simple questions that could easily be found 
on the net.

The OpenBSD kernel is quite modular; to get a look at just the 
arm-specific portions you need to look in arch/arm (general arm stuff) 
and arch/armish (one example of a full port, the Thecus and compatible 
machines, see www.openbsd.org/armish.html). That said, the wc for your 
interest is as follows:

   find . -type f -a \( -name \*.c -o -name \*.h \) | egrep 
'./(altq,arch/arm)|./[b-zM]' | xargs cat | wc -l

The answer is 2401896, just over 2M LOC. That does include a lot of 
optional stuff.

You can get the source from multiple places and answer any further 
inquiries yourself; see www.openbsd.org for details. Kernel study is 
meant to be do-it-yourself, not always be asking for help. Good luck!

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