Format a USB flash drive using gpart

Wojciech Puchar wojtek at
Mon Jul 9 10:26:26 UTC 2012

> If you're talking about an MS-DOS disk, then yes, it contains
> a DOS partition which is formatted. In FreeBSD, we would call
> it a slice (slice == "DOS primary partition"). In this case,
> there is no (sub)partitioning, the _slice_ carries the MS-DOS

unless you need windows 98 support partitionless USB drives works 
absolutely fine

clear it out

dd if=/dev/zero of=/dev/da0 bs=64k count=1


newfs_msdos /dev/da0

>> Same question for CDs?
> Not sure. A CD contains an ISO-9660 file system without an
> enclosing partition per se.
In FreeBSD (as well as NetBSD, OpenBSD, maybe linux) CD is just block 
device. You may make disklabel on it, and whatever you like.

In excuse of OS (windows) CD/DVD MUST BE CD9660 or UDF formatted without 

You may record NTFS formatted DVD, perfectly readable on FReeBSD, 
unreadable under windows in spite it is windows native filesystem.

You may actually make "hybrid" DVD that will show whatever you want under 
windoze, and have real data in tar format.

below the recipe:

1) prepare windows-vizible layout, all needed viruses and autorun.inf in 
some directory and do

mkisofs -J -q .|dd of=/path/to/tempfile bs=512 skip=1


tar cf - /path/to/tempfile ...list of what you want to be tarred...|growisofs -dvd-compat -Z /dev/cd0=-

now use tar to read files from that DVD, while in windows it will run 
viruses properly.

>> a virtual partition?
> As devices and "real files" are "quite the same", you can mount
> a file system that is contained in a file. You typically do this
> when doing data recovery and forensic analysis, where your starting
> point is an image file of a disk, a slice or a partition. You
> then "connect" it to a virtual node (vnconfig - e. g. md0) and

vnconfig is quite in old FreeBSD
today it is mdconfig

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