Re: Formatting FAT32 newfs_msdos returns read-only file system

[RVP <rvp%SDF.ORG@localhost>]

On Mon, 21 Sep 2026, John D. Baker wrote:

> On Mon, 21 Sep 2026, RVP wrote:
>
> > You can't start a MBR partition on sector 1 (ie. track 0) on HDD-type
> > media.  Start on track 1--or sector 2048 as per the alignment it wants
> > to be in.
>
> That depends.  I routinely start MBR partitions in sector 1.  Only in
> a couple of cases has that been rejected, although I forget the context.
> In those cases, I didn't have to offset much for it to work.  Admittedly
> in the FreeDOS case below, I only partitioned the disk w/NetBSD, all the
> formatting and setup (of the DOS partitions) were done with FreeDOS.

I would be very surprised if NetBSD allowed direct writes to sector 1. That's
where the disklabel resides (for NetBSD on the 1st partn.) and direct writes
should be rejected by the system. Writing a disklabel is therefore done using
an ioctl, I believe--mlelstv@ mentioned this some time back.

-RVP