Either use parameters provided by user or make them up.
The code for faking CHS params is borrowed from disklabel code.
The logic for using user-provided and auto-guessed parameters is not
perfect, so to speak.
PR: bin/121182
Approved by: jhb (mentor)
when preparing images for emulators or flash devices:
+ option '-C size' to create the underlying image file with given size.
Saves doing a 'dd' before, and especially it creates a sparse file
+ option '-@ offset' to build the FAT image at the specified offset
in the image file or device;
+ make the cluster size adaptive on the filesystem size.
Previously the default was 4k which is really unconvenient with
large media; now it goes from 512 bytes to 32k depending on
filesystem size (i still need to check whether it makes sense
to go further up, to 64k or above);
+ fix default geometry when not specified on the command line,
use 63 sectors/255 heads by default.
Also trim the size so it exactly a multiple of a track, to avoid
complaints in some filesystem code.
+ document all the above, plus some manual page clarifications.
MFC after: 4 weeks
a plain file and a geometry is not explicitly supplied through
command line or disktab entry.
This way you can a FAT image on a file as simply as this:
newfs_msdos ./some/file
(right now you need a much longer command
newfs_msdos -h 32 -u 64 -S 512 -s $total_blocks -o 0 ./some/file
Will be merged after 7.1 and 6.4 are released.
See also the related PR which suggests a similar change.
PR: bin/121182
MFC after: 4 weeks
correct place on large sector disks. The boot signature should be at
offset 0x1fe in the BPB; newfs_msdos currently stores it 2 bytes from
the end of the sector.
Taken from: NetBSD
- Initialize everything in the struct array, not only the mentioned
ones
- Unconditionally initialize hs to 0 to avoid repeatly doing so
- Cast to unsigned int when comparing to unsigned variables.
getdiskinfo(). For the fixed-disk case, bpb->hid probably isn't
handled correctly, but I'm not sure if this is a serious problem since
the primary use of this program is to format floppy disks.
Reviewed by: phk
