Re: bsd-style partitioning

[Martin Ostermann <ost comnets rwth-aachen de>]

On Thu, 11 Feb 1999 08:32:26 -0800 (PST), Marc Alvidrez <alvia@ocf.berkeley.edu> said:
> Is writing a disklabel an irreprable act?  After I write a disklabel, will

Basically, yes. It will destroy the previous fdisk label. But it will
not touch the existing partitions. It would be theoretically possible
to create an bsdlabel whose partitions access the same areas as the
previous fdisk label. The biggest problem involves "logical drives" in
the extended partition: there are 1 or 2 blocks used for linear
linking all "logical drives" together, so the bsdlabel partition must
not start on the beginning of the cylinder, but one or two blocks
later.

> I be unable to boot from a floppy with the "root= /dev/sda2" flag? 

Since /dev/sda2 used to be a primary partition, I guess you'd be able to
install the bsdlabel in such a way that this is possible.

> How are bsd partitions accessed (does /dev/sda2 = /dev/c0t0d0s1).  

They get maped to /dev/sda*, but I don't know exactly how.

> bsd-style partitions, will I need to make sure that I create new devices? 

No, you don't need to.

> What about /etc/fstab? 

It basicallly looks the same.

> My current partition table looks like this:

> Disk /dev/sda: 141 heads, 62 sectors, 1018 cylinders
> Units = cylinders of 8742 * 512 bytes

>    Device Boot    Start      End   Blocks   Id  System
> /dev/sda2             2       48   205437   83  Linux native
> /dev/sda3            49     1018  4239870    5  Extended
> /dev/sda5            49      236   821717   83  Linux native
> /dev/sda6           237      476  1049009   83  Linux native
> /dev/sda7           477      505   126728   82  Linux swap
> /dev/sda8           506      681   769265   83  Linux native

> Can I just ignore the extended partition when defining the bsd partitions
> so that it will look something like: 

> Partition       Mount Point     Start   End
> 0               /               2       48

Yes.

> 1               swap            477     505

you could reinitalize swap, than that will work ...

> 2               whole disk      0       1018

I had problems with such an entry, because different kernel versions
did the mapping differently. Suddenly /dev/sda4 became /dev/sda3 ...
If you don't intend to use this (e.g. for backup), I would skip it.

> 6               /usr            49      236
> 7               /home           237     476

No, because of those extra blocks in the extended partiton.

HTH, Martin
-- 
Martin Ostermann                | mailto:ost+sig0@comnets.rwth-aachen.de
Communication Networks          | http://www.comnets.rwth-aachen.de/~ost
Aachen University of Technology | phone: ++49/241/807917
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