8.0-RELEASE and "dangerously dedicated" disks

[Rolf G Nielsen]

Polytropon wrote:
> On Wed, 2 Dec 2009 13:09:22 -0500, Jerry McAllister <jerrymc at msu.edu> wrote:
>> Good.   Except that in FreeBSD land you are talking about a slice table.
>> To carry things forward consistently, the partition table is within
>> a slice and describes FreeBSD partitions a..h (and more now I guess).
>> Only in MS or Lunix land should primary divisions be called partitions
>> and then they are _primary_ partitions.
> 
> To be most precise, they are called "DOS primary partitions".
> As far as I know, the need for them has been massively by
> MICROS~1 operating systems (DOS, "Windows").
> 
> That what FreeBSD calls partitions are subdivions of
> slices. A partition holds a file system (each), while a
> slice holds partitions. Those partitions could be compared
> to what MICROS~1 calls "logical volumes inside a DOS extended
> partition", allthoug that's just a *comparison* and not
> an exact equivalent.
> 
> 
> 
>> But, even some of the fdisk and other documentation still mucks this
>> up and occasionally refers to slices as partitions.   Maybe we can
>> come up with some new terminology like  'blobs'  and  'dollops'  to get 
>> away from the problem.
> 
> Borrow some artificially created fantasy words from modern
> KDE or Gnome application development? :-)
> 
> An idea that follows your inspiration could be:
> 
> 	(old) slice => (new) primary partition 
> 	eq. DOS primary partition
> 
> 	(old) partition => (new) secondary partition,
> 		alt. (new) subpartition
> 	comp. logical volumes inside a DOS extended partition
> 
> But it would help to get at least FreeBSD's documentation
> consistent, even if it uses the non-MICROS~1 names for
> things (which is very fine for me).
> 
> Note that the limitation to 4 slices per disk - we remember
> that we are talking about "DOS primary partitions" here -
> is grounded in the fact that MICROS~1 stuff doesn't seem
> to be able to handle more than 4, a legacy restriction from
> the past. I've not yet tested if it's possible to create
> e. g. ad0s1, ad0s2, ad0s3, ad0s4 and ad0s5 with FreeBSD,
> but it should be possible.
> 
> (Because multi-booting PCs respectively their operating
> systems eat up primary partitions like coockies, often
> people complain that they can't install FreeBSD because
> it requires a primary partition as well. Mostly, people
> don't have 4 OSes on their disks, but the one or two
> they often have (e. g. a Linux and a "Windows") have
> already occupied adX0..adX3.)
> 
> 

Hi all,

Out of curiousity, I just tested to bsdlabel a disk I had lying around. 
In dangerously dedicated mode. No problem at all. I newfs'd it and 
mounted it. Also no problem. I haven't tried to boot from it though, but 
I may do that later, when I have nothing running that can't be halted.

I did config -x /boot/kernel/kernel and I noticed that GEOM_PART_BSD was 
there, though I'm absolutely certain I haven't included it, and if I 
understand correctly, it shouldn't be there unless explicitly included?
I'm running 8.0-RELEASE-p1 amd64 with a custom kernel config. However 
the kernel config file was more or less copied from 7.2, with just a 
little tweaking. I guess I should create a new one, using sys/conf/NOTES 
and sys/amd64/conf/NOTES as guidelines and sys/amd64/conf/GENERIC as 
template, but I haven't gotten around to that yet.

Anyway, is GEOM_PART_BSD supposed to be there (I just checked, and 
noticed it's in sys/amd64/conf/DEFAULTS) or can I safely remove it? And 
will it, considering I migrated to gpt and zfs, be meaningful to remove 
it (e.g. will it make the kernel smaller or have any positive impact on 
zfs performance)? And should DD disks work except to boot from, or 
shouldn't they work at all?

Sincerely,

Rolf Nielsen