Re: OS/2 HPFS File System - Is this a Bug? + a note for the list maintainers

[Jim Worthington <jworthington@worldnet.att.net>]

Martin Str|mberg wrote:
> 
> Hello.
> 
> jworthington@worldnet.att.net said:
> >
> > I'm running OS/2 Warp with HPFS on several of my drives.
> >
> > I noticed that Linux 1.1 fdisk reveals two different file system
> > identifiers for HPFS partitions:
> >
> >   /dev/sda5  id 7  OS/2 HPFS
> >
> >   /dev/hda2  id 17 Unknown
> >
> >
> > Has anybody else observed the two different identifers for HPFS
> > filesystems?  Is this a Bug?  Linux produces some error messages when
> > mounting the id 17 filesystem but it everything seems to work ok.  I
> > didn't observe any error messages when mounting the id 7 filesystem
> > which also works fine.
> 
> Yes. I have this behaviour in my system as well, although in my case it's
> a FAT partition. I have two primary ones on my first hard disk, so one is
> always hidden (for DOZ and OS/2).
> 
> When I check out the partion types with fdisk under Linux I see that the
> partition that is considered hidden has id 16 in contrast to the one that
> isn't hidden, id 6. Then if I make the hidden one unhidden (and the other
> one hidden) the ids have changed places.
> 
> How about that,
> 
> MartinS

I think that you've hit the nail on the head!

I'm running 3 primary partitions (Win95, OS/2, OS/2 Boot Manager) and 2
extended partitions (Linux, Linux Swap).  I believe that OS/2 Boot
manager automatically makes the unselected primary partition hidden. 
The last invoked primary partition is left in the un-hidden state.

I just booted up OS/2 using Boot Manager to make the OS/2 partition
unhidden.  I then booted Linux also via OS/2 Boot Manager.  Fdisk
reported:

         /dev/hda1  id 16  Unknown   (previously reported as id 6)
         /dev/hda2  id  7  OS/2 HPFS

The OS/2 partition is now being reported correctly and the Win95 FAT
partition is being reported as Unknown.

Now, What is the solution to the problem?  Do we indeed have 2 new
partition types:

         id 16  Dos FAT   (hidden)
         id 17  OS/2 HPFS (hidden)

Or is it possible that Linux fdisk is mis-reading a partition table bit
that serves some other purpose than (id)?  OS/2 makes reference to
partitions that are <bootable> and <startable>.  How are these
attributes dealt with under Linux?

Jim