Re: Extended Linux partition

Dan Merillat (
Tue, 3 Oct 1995 07:33:37 -0400 (EDT)

On Mon, 2 Oct 1995, Albert Cahalan wrote:

> > it might be a good idea to work around this problem in Linux by creating
> > a new partition type: Linux extended partitions. It would work exactly
> > the same as the normal DOS extended partitions, but a different partition
> > type byte would not confuse the DOS FDISK program.
> Or not so trivial: use 64-bit linear sector numbers in
> a fixed table with room for 16+ partitions.

YES! Room to grow is a very good idea since we are making a
new type anyway.

> > The change in linux/drivers/block/genhd.c seems trivial to me. Now here
> > is another, less trivial idea: to work around the limitations of the
> > standard PC partitioning system, maybe it should be possible to add
> > (or remove) partitions dynamically at run time? All that is necessary
> > at boot time is the root partition, the rest can be added later by some
> > special program reading some partition config file and using some new
> > ioctl calls on /dev/[hs]d?. That might also be useful for removable
> > disks like SyQuest (but I don't have one: how are they handled now?).
> This is a very good idea, /dev/vbd?, the virtual block device.
> Any contiguous group of sectors can become a block device.
> This lets an unfragmented file (say, the Windows swap file)
> become a swap _partition_ with full speed advantages or an
> ext2 partition inside a floppy disk image. Access to the virtual
> block device does not go through the filesystem it resides on.

Ohhboy could I have fun with that. But let's keep it out
of the kernel for a while yet shall we? A nice block device
driver as a module dist'd seperate until the problems are solved.
I don't want to hear screams of "I wiped out my entire DOS disk!"
from someone who didn't know what they were doing. :-(

Actually, how much work would it take? The only difference between
that and the normal device driver is locating the starting/ending marks
correct? Anyway, I'd be happy to alpha test but my linux box is
down for a MB replacement -- so probably in the next 2 weeks or so
I'll check it out.

Dan Merillat <>
(Harik A'ttar) <>
Animaniac! Linux Activist and net.junkie