Advice for hacking on ufs/ffs

[Shane Adams]

Thanks for the tip DES!  I will probably break down and buy a cheap machine or dust off my old P3 box.  I have a PXE card at home too.  I want to try qemu as well cause if I get it to work I can tool around on my laptop.

Eric, I hate to bother you but I didn't get the cheat sheet.  Here's what I attempted last night.

I built qemu from ports
I used dd to create 1G file.
I did mdconfig -a -t vnode -f /bigdrive/bsdfilesystem -u 0
I downloaded the 20M boot only ISO.

I ran qemu specifying -cdrom as the 20M iso, and -hda to /bigdrive/bsdfilesystem.

Qemu started fine, and I proceeded to go through the basic install process, at that point it asked me to toss in the correct CD with the packages to complete the installation (Which I didnt' have the CD handy and it was late so I will try again tonight).

Anyway - you said you do a make DESTDIR to your mdconfig'd file.  Did you mount the file you mdconfiged?  If so, does a make installworld install a boot loader as well?  I'm not clear on how you used qemu to boot agains that device.  Perhaps you did a normal BSD install on it then later mounted it to get your stuff on there?

Cheers,
  Shane


----- Original Message ----
From: Eric Anderson <anderson at centtech.com>
To: Dag-Erling Smørgrav <des at des.no>
Cc: Shane Adams <adamsch1 at yahoo.com>; freebsd-fs at freebsd.org
Sent: Tuesday, July 25, 2006 9:13:01 AM
Subject: Re: Advice for hacking on ufs/ffs

On 07/25/06 10:13, Dag-Erling Smørgrav wrote:
> Shane Adams <adamsch1 at yahoo.com> writes:
>> I'm a programmer that is new to kernel development.  I'm interested
>> in hacking around on UFS and FFS.  I only have one machine so I
>> copied the complete sys/ufs code to a new directory under fs, and
>> changed a few things to get it to compile and mount.  Everything
>> works, and I was ready to start hacking without worrying so much
>> about screwing up my system.
>>
>> Naturally I've rebooted the machine a few times since then, and I
>> was wondering if anyone has advice for a fledgling kernel
>> programmer.  (Best practices)
> 
> Get a test machine with a PXE-capable network adapter, and set up your
> workstation as bootp / dhcp and NFS server.  Having a dedicated test
> box will save time as you won't have to reboot your workstation to
> test your code, and setting it up diskless will help even further.  A
> serial console cable will help even more, as it will save you from
> moving from one keyboard to another and will give you a scrollback of
> the test machine's console from which you can copy / paste error
> messages, backtraces etc.
> 
> DES


DES - anything special with the nfs root'ed box, to make this work well? 
  The only reason I didn't set this up for my work is because it isn't 
portable.. :)

Eric


-- 
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Eric Anderson        Sr. Systems Administrator        Centaur Technology
Anything that works is better than anything that doesn't.
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