Bash script to format a block device (hard drive or Flash drive) in UDF. The output is a drive that can be used for reading/writing across multiple operating system families: Windows, OS X, and Linux. This script should be capable of running in OS X or in Linux.
- Formats a block device (hard drive or Flash drive) in Universal Disk Format (UDF)
- UDF revision 2.01 used for maximal compatibility (see note on Linux support below)
- Resulting file system can be read/written across multiple operating system families (Windows, OS X, and Linux)
- Runs on any OS having a Bash environment
- Ability to override detected device block size
- Option to force non-interactive mode (useful for scripting)
- Optionally wipes device before formatting
- Writes a fake MBR for added compatibility on Windows (optionally disabled)
For the advanced user, this script is also capable of formatting a single existing partition, without modifying the partition table. Beware that using this method will render the newly formatted UDF partition unusable on OS X (but still usable on Linux and Windows). (See #24 for caveats.) Because of this limitation, the recommendation is to format the entire device.
Following tables detail operating system support for UDF. Data was adapted from https://en.wikipedia.org/wiki/Universal_Disk_Format#Compatibility (as retrieved on 2015-Feb-20).
Both read/write are supported unless otherwise listed below.
| Operating System | Read-only | Note |
|---|---|---|
| Mac OS X 10.5, 10.6, 10.7, 10.8, 10.9, 10.10 | ||
| Windows Vista, 7, 8 | Referred to by Microsoft as "Live File System"; Requires fake full-disk partition | |
| Windows XP, Server 2003 | Read-only | Write support available with third party utilities |
| Linux 2.6, 3.x | UDF revisions 2.01 and before have read/write. After 2.01, read-only. | |
| AIX 5.2, 5.3, 6.1 | ||
| BeOS, magnussoft ZETA, Haiku | ||
| DosBox | ||
| eComStation, OS/2 | Additional-fee drivers on OS/2 | |
| NetBSD 5.0 |
| Operating System | Note |
|---|---|
| Windows 95 OSR2+, 98, Me | Utilities include DLA and InCD |
| Windows 2000 |
| Operating System | Note |
|---|---|
| DOS, FreeDOS, Windows 3.11 or older | Filesystems that have an ISO9660 backward compatibility structure can be read |
- Any OS having a Bash environment
- The following tools must be installed, executable, and in the PATH:
- printf
- xxd
- One of the following: blockdev, diskutil
- One of the following: umount, diskutil
- One of the following: mkudffs, newfs_udf
To install necessary prerequisites on Ubuntu:
sudo apt-get install udftools coreutils vim-common
Simply copy format-udf.sh to a directory of your choosing. Don't forget to make it executable:
chmod +x format-udf.sh
Usage: ./format-udf.sh [-b BLOCK_SIZE] [-f] [-p PARTITION_TYPE] [-w WIPE_METHOD] device label
-b BLOCK_SIZE
Block size to be used during format operation.
If absent, defaults to value reported by blockdev/diskutil.
This is useful in light of the following Linux kernel bug:
https://bugzilla.kernel.org/show_bug.cgi?id=102271
See also:
https://github.com/JElchison/format-udf/issues/13
-f
Forces non-interactive mode. Useful for scripting.
Please use with caution, as no user confirmation is given.
-p PARTITION_TYPE
Partition type to set during format operation.
Currently supported types include: mbr, none
mbr - Master boot record (default)
none - Do not modify partitions
If absent, defaults to 'mbr'.
See also:
https://github.com/JElchison/format-udf#a-fake-partition-table-to-fake-out-windows
-w WIPE_METHOD
Wipe method to be used before format operation.
Currently supported types include: quick, zero, scrub
quick - Quick method (default)
zero - Write zeros to the entire device
scrub - Iteratively writes patterns on device
to make retrieving the data more difficult.
Requires 'scrub' to be executable and in the PATH.
See also http://linux.die.net/man/1/scrub
If absent, defaults to 'quick'.
Note: 'zero' and 'scrub' methods will take a long time.
device
Device to format. Should be of the form:
* sdx (Linux, where 'x' is a letter) or
* diskN (OS X, where 'N' is a number)
label
Label to apply to formatted device.
Example: ./format-udf.sh sdg "My External Drive"
On Ubuntu:
user@computer:~$ ./format-udf.sh sdg "My UDF External Drive"
[+] Testing dependencies...
[+] Looking for drive listing tool... using /sbin/blockdev
[+] Looking for unmount tool... using /bin/umount
[+] Looking for UDF tool... using /usr/bin/mkudffs
[+] Parsing options...
[+] Validating arguments...
[+] Gathering drive information...
[sudo] password for user:
/dev/sdg: LABEL="Old Drive" TYPE="udf"
HTS721010G9SA00
RO RA SSZ BSZ StartSec Size Device
rw 256 512 4096 0 100030242816 /dev/sdg
The above-listed device (and partitions, if any) will be completely erased.
Type 'yes' if this is what you intend: yes
[+] Detecting total size...
[*] Using total size of 100030242816
[+] Validating detected total size...
[+] Detecting physical block size...
[*] Using block size of 512
[+] Validating detected block size...
[+] Unmounting device...
umount: /dev/sdg: not mounted
[+] Zeroing out first chunk of device...
4096+0 records in
4096+0 records out
2097152 bytes (2.1 MB) copied, 0.531167 s, 3.9 MB/s
[+] Formatting /dev/sdg ...
start=0, blocks=64, type=RESERVED
start=64, blocks=12, type=VRS
start=76, blocks=180, type=USPACE
start=256, blocks=1, type=ANCHOR
start=257, blocks=16, type=PVDS
start=273, blocks=1, type=LVID
start=274, blocks=195371037, type=PSPACE
start=195371311, blocks=1, type=ANCHOR
start=195371312, blocks=239, type=USPACE
start=195371551, blocks=16, type=RVDS
start=195371567, blocks=1, type=ANCHOR
[+] Writing fake MBR...
16+0 records in
16+0 records out
16 bytes (16 B) copied, 0.00259109 s, 6.2 kB/s
2+0 records in
2+0 records out
2 bytes (2 B) copied, 0.000108835 s, 18.4 kB/s
[+] Successfully formatted /dev/sdg: LABEL="My UDF External Drive" TYPE="udf"
Please disconnect/reconnect your drive now.
On OS X:
computer:~ user$ ./format-udf.sh disk2 "My UDF External Drive"
[+] Testing dependencies...
[+] Looking for drive listing tool... using /usr/sbin/diskutil
[+] Looking for unmount tool... using /usr/sbin/diskutil
[+] Looking for UDF tool... using /sbin/newfs_udf
[+] Parsing options...
[+] Validating arguments...
[+] Gathering drive information...
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: Old Drive *100.0 GB disk2
The above-listed device (and partitions, if any) will be completely erased.
Type 'yes' if this is what you intend: yes
[+] Detecting total size...
[*] Using total size of 100030242816
[+] Validating detected total size...
[+] Detecting physical block size...
[*] Using block size of 512
[+] Validating detected block size...
[+] Unmounting device...
Password:
Unmount of all volumes on disk2 was successful
[+] Zeroing out first chunk of device...
4096+0 records in
4096+0 records out
2097152 bytes transferred in 0.592766 secs (3537908 bytes/sec)
[+] Formatting /dev/disk2 ...
write to block device: /dev/disk2 last written block address: 195371567
[+] Writing fake MBR...
16+0 records in
16+0 records out
16 bytes transferred in 0.044496 secs (360 bytes/sec)
2+0 records in
2+0 records out
2 bytes transferred in 0.000602 secs (3322 bytes/sec)
[+] Successfully formatted
Please disconnect/reconnect your drive now.
As tested in the lab...
| Device Type | Block Size | Formatted on | Inserted on Ubuntu | Inserted on OS X |
|---|---|---|---|---|
| Flash | 512 | Ubuntu 14.04 | Success | Success |
| Flash | 512 | OS X 10.11 | Success except label, see #11 | Success |
| HDD (USB) | 512 | Ubuntu 14.04 | Success | Success |
| HDD (USB) | 512 | OS X 10.11 | Success except label, see #11 | Success |
If's extremely important that format-udf.sh use the correct block size when formatting your drive. The script will attempt to detect and use the correct block size. However, in rare cases (such as #13), Linux can lie about the block size. OS X is known to report the incorrect block size in certain scenarios as well. In these cases, the format-udf -b BLOCK_SIZE option can be used to explicitly set it.
If the wrong block size is used (i.e. one that doesn't match the geometry of your drive), the resultant drive will likely have non-optimal performance issues, and may not use the drive's entire storage capacity.
In the same way, it's just as important that the resultant drive be mounted using the correct block size. Many operating systems will only attempt one block size (usually whatever the mount utility defaults to). If your block size isn't the OS's default, then auto-mounting likely will not work on your OS. While a small nuisance, manual mounting attempts should still succeed for nonstandard block sizes.
Example of how to manually mount on Linux:
$ mount -t udf -o bs=4096 /dev/sdX /mnt/mount-point
Example of how to manually mount on OS X:
$ sudo mount_udf -b 4096 /dev/diskN /Volumes/MountPoint
Sadly, anything with block size different than 512 doesn't seem to mount on Windows.
For more info, see #12, #16, and #31.
For maximal compatibility, use format-udf on an entire device in one of the following configurations:
- Run format-udf on Linux
- Run format-udf on OS X, but modify the drive label using Linux or Windows
As mentioned by Pieter here, Windows does not support hard disks without a partition table. This is strange because Windows does not apply the same limitation to flash drives.
To make matters worse, OS X only uses UDF disks that utilize the full disk (not just a partition).
The solution, as suggested by Pieter, is to place a fake partition table (via MBR) in the first block of the drive, which lists a single entire-disk partition. This works because UDF (perhaps intentionally) doesn't utilize the first block. Unfortunately, there has been no easy way to do this, while juggling all of the other variables (such as device physical block size).
format-udf writes such a fake MBR for added compatibility on Windows.
If this is not what you desire, you can disable the MBR with -p none.
After installing GRUB2 on a partitionless drive, you can use fdisk to set the partition as active if your BIOS can't boot from partitionless drives. (Thanks to @tome- for the tip.)