Mounting a NetBSD partition from OpenBSD

[daemonfowl]

Hello !

I'd be thankful if anyone would explain why this is the case :
In OpenBSD :
Mounting an external OpenBSD ffs partition (eg. /dev/sd0h ) , this line in fstab will do the job :

/dev/sd0h /home/daemonf/ffs ffs ro,noauto 0 0

But mounting a NetBSD partition in OpenBSD , /dev/sd0a won't work .. instead :

/dev/sd0i /home/daemonf/ffs ffs ro,noauto 0 0

is it because I allocated only one big partition for / ? then it takes sd0i ?
In what way is it similar to a msdos disk then ?

The other question :
When I mount an external ffs as rw , most times it works without problems but I recall a few times when I received warning messages (that I need to check filesystem .. or simply fail to mount one rw )
Why do both instances happen ?

Thank you so much !!

[daemonfowl]

And to mount a external NetBSD partition in NetBSD I must use /dev/sd0a (and not /sd0i .. OpenBSD's case)
Why is it so ?

[jggimi]

You're asking a NetBSD operational question in an OpenBSD thread.

On OpenBSD, if there is no OpenBSD disklabel on a drive with an MBR, any recognized MBR partitions are assigned virtual partition letters starting with "i". This has nothing to do with NetBSD, Windows, or any other OS. This has only to do with recognized foreign partition types in an MBR partition table.

Those virtual disklabel entries may become physical disklabel entries if an OpenBSD disklabel is written.

[daemonfowl]

Hi Teacher jggimi !
I meant it as OpenBSD thread since it involves it mainly and for comparison too.
Thank you for the clear explanation. :-)
(How much I miss .. poor me !)

[roddierod]

Originally Posted by daemonfowl

Hello !

I'd be thankful if anyone would explain why this is the case :
In OpenBSD :
Mounting an external OpenBSD ffs partition (eg. /dev/sd0h ) , this line in fstab will do the job :

/dev/sd0h /home/daemonf/ffs ffs ro,noauto 0 0

But mounting a NetBSD partition in OpenBSD , /dev/sd0a won't work .. instead :

/dev/sd0i /home/daemonf/ffs ffs ro,noauto 0 0

is it because I allocated only one big partition for / ? then it takes sd0i ?
In what way is it similar to a msdos disk then ?

The other question :
When I mount an external ffs as rw , most times it works without problems but I recall a few times when I received warning messages (that I need to check filesystem .. or simply fail to mount one rw )
Why do both instances happen ?

Thank you so much !!

I know this to be true in the case of FreeBSD and NetBSD, so I assume it to be true with NetBSD and OpenBSD and that is this.

Although the BSDs file systems are all called UFS/FFS they each have different implementation of it. Therefore, trying to mount a NetBSD file system on a OpenBSD as if it's a native file system is not going to work. You have to keep in mind that the BSDs are all separate OS and though they share a common ancestor. Not a direct answer, but maybe it will help you to understand why.