USB flash drives can be used to share data among machines. After attaching it we can see via dmesg(8) that it is recognised as sd0:

# dmesg
[...]
sd0 at scsibus0 target 0 lun 0: <Kingston, DataTraveler 3.0, > disk removable
sd0: fabricating a geometry
sd0: 14755 MB, 14755 cyl, 64 head, 32 sec, 512 bytes/sect x 30218842 sectors
sd0: fabricating a geometry
[...]

To initialize it we can write zeros in the first 1MB of the USB flash drive:

# dd if=/dev/zero of=/dev/rsd0d bs=1m count=1
1+0 records in
1+0 records out
1048576 bytes transferred in 0.118 secs (8886237 bytes/sec)

Via fdisk(8) we can create a partition table. MS-DOS partition and filesystem is supported by most operating systems and devices that accept an USB disk, so let's update the partition table (-u), creating an MS-DOS partition and set the new partition as active (-a):

# fdisk -au sd0
fdisk: primary partition table invalid, no magic in sector 0
fdisk: Cannot determine the number of heads
Disk: /dev/rsd0d
NetBSD disklabel disk geometry:
cylinders: 14755, heads: 64, sectors/track: 32 (2048 sectors/cylinder)
total sectors: 30218842, bytes/sector: 512

BIOS disk geometry:
cylinders: 1023, heads: 255, sectors/track: 63 (16065 sectors/cylinder)
total sectors: 30218842

Partitions aligned to 16065 sector boundaries, offset 63

Do you want to change our idea of what BIOS thinks? [n] 

Partition table:
0: <UNUSED>
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
Bootselector disabled.
No active partition.
Drive serial number: 0 (0x00000000)
Which partition do you want to change?: [none] 0
The data for partition 0 is:
<UNUSED>
sysid: [0..255 default: 169] 11
start: [0..1881cyl default: 63, 0cyl, 0MB] 
size: [0..1881cyl default: 30218779, 1881cyl, 14755MB] 
bootmenu: [] (space to clear) 

Partition table:
0: Primary DOS with 32 bit FAT (sysid 11)
    start 63, size 30218779 (14755 MB, Cyls 0-1881/9/10)
        PBR is not bootable: All bytes are identical (0x00)
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
Bootselector disabled.
No active partition.
Drive serial number: 0 (0x00000000)
Which partition do you want to change?: [none] 
Do you want to change the active partition? [n] y
Choosing 4 will make no partition active.
active partition: [0..4 default: 4] 0
Are you happy with this choice? [n] y

We haven't written the MBR back to disk yet.  This is your last chance.
Partition table:
0: Primary DOS with 32 bit FAT (sysid 11)
    start 63, size 30218779 (14755 MB, Cyls 0-1881/9/10), Active
        PBR is not bootable: All bytes are identical (0x00)
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>
Bootselector disabled.
First active partition: 0
Drive serial number: 0 (0x00000000)
Should we write new partition table? [n] y

Then we can see via disklabel(8):

# disklabel sd0
# /dev/rsd0d:
type: SCSI
disk: DataTraveler 3.0
label: fictitious
flags: removable
bytes/sector: 512
sectors/track: 32
tracks/cylinder: 64
sectors/cylinder: 2048
cylinders: 14755
total sectors: 30218842
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # microseconds
track-to-track seek: 0  # microseconds
drivedata: 0

5 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 d:  30218842         0     unused      0     0        # (Cyl.      0 -  14755*)
 e:  30218779        63      MSDOS                     # (Cyl.      0*-  14755*)
disklabel: boot block size 0
disklabel: super block size 0

that an sd0e MSDOS partition is present.

We can finally create an MS-DOS filesystem via newfs_msdos(8):

# newfs_msdos /dev/rsd0e
/dev/rsd0e: 30189264 sectors in 1886829 FAT32 clusters (8192 bytes/cluster)
MBR type: 11
bps=512 spc=16 res=32 nft=2 mid=0xf0 spt=32 hds=64 hid=0 bsec=30218779 bspf=14741 rdcl=2 infs=1 bkbs=2

It is ready to be used and mounted via mount_msdos(8).

PC-style floppy disks work mostly like other disk devices like hard disks, except that you need to low-level format them first. To use an common 1440 KB floppy in the first floppy drive, first (as root) format it:

# fdformat -f /dev/rfd0a

Then create a single partition on the disk using disklabel(8):

# disklabel -rw /dev/rfd0a floppy3

Creating a small filesystem optimized for space:

# newfs -m 0 -o space -i 16384 -c 80 /dev/rfd0a

Now the floppy disk can be mounted like any other disk. Or if you already have a floppy disk with an MS-DOS filesystem on it that you just want to access from NetBSD, you can just do something like this:

# mount -t msdos /dev/fd0a /mnt

However, rather than using floppies like normal (bigger) disks, it is often more convenient to bypass the filesystem altogether and just splat an archive of files directly to the raw device. E.g.:

# tar cvfz /dev/rfd0a file1 file2 ...

A variation of this can also be done with MS-DOS floppies using the sysutils/mtools package which has the benefit of not going through the kernel buffer cache and thus not being exposed to the danger of the floppy being removed while a filesystem is mounted on it.

Data CDs can contain anything from programs, sound files (MP3, wav), movies (MP3, QuickTime) to source code, text files, etc. Before accessing these files, a CD must be mounted on a directory, much like hard disks are. Just as hard disks can use different filesystems (ffs, lfs, ext2fs, ...), CDs have their own filesystem, "cd9660". The NetBSD cd9660 filesystem can handle filesystems without and with Rockridge and Joliet extensions.

CD devices are named /dev/cd0a for both SCSI and IDE (ATAPI).

With this information, we can start:

Use mscdlabel(8) to add all sessions to the CDs disklabel, and then use the appropriate device node to mount the session you want. You might have to create the corresponding device nodes in /dev manually. For example:

# mscdlabel cd1
track (ctl=4) at sector 142312
 adding as 'a'
track (ctl=4) at sector 0
 adding as 'b'
# ls -l /dev/cd1b
ls: /dev/cd1b: No such file or directory
# cd /dev
# ls -l cd1*
brw-r-----  1 root  operator       6,  8 Mar 18 21:55 cd1a
brw-r-----  1 root  operator       6, 11 Mar 18 21:55 cd1d
# mknod cd1b b 6 9

to create /dev/cd1b. Make sure you fix the permissions of any new device nodes you create:

# ls -l cd1*
brw-r-----  1 root  operator       6,  8 Mar 18 21:55 cd1a
brw-r--r--  1 root  wheel          6,  9 Mar 18 22:23 cd1b
brw-r-----  1 root  operator       6, 11 Mar 18 21:55 cd1d
# chgrp operator cd1b
# chmod 640 cd1b
# ls -l cd1* 
brw-r-----  1 root  operator       6,  8 Mar 18 21:55 cd1a
brw-r-----  1 root  operator       6,  9 Mar 18 22:24 cd1b
brw-r-----  1 root  operator       6, 11 Mar 18 21:55 cd1d

Now you should be able to mount it.

# mount /dev/cd1b /mnt

By default, NetBSD only allows "root" to mount a filesystem. If you want any user to be able to do this, perform the following steps:

To perform the mount operation after these commands, the user must own the mount point. So, for example:

$ cd $HOME
$ mkdir cdrom
$ mount -t cd9660 -o nodev,nosuid /dev/cd0a `pwd`/cdrom

Please also see mount(8) and as an alternative the auto mount daemon amd(8), for which example config files can be found in /usr/share/examples/amd.

Sometimes, it is interesting to mount an ISO9660 image file before you burn the CD; this way, you can examine its contents or even copy files to the outside. If you are a Linux user, you should know that this is done with the special loop filesystem. NetBSD does it another way, using the vnode pseudo-disk.

We will illustrate how to do this with an example. Suppose you have an ISO image in your home directory, called "mycd.iso":

Note that these steps can also be used for any kind of file that contains a filesystem, not just ISO images.

See the vnd(4) and vnconfig(8) man pages for more information.

To play MPEG Video streams as many DVD players can play them under NetBSD, mount the CD as you would do with any normal (data) CD (see Section 13.4, “Reading data CDs with NetBSD”), then use the multimedia/xine-ui, multimedia/mplayer or multimedia/gmplayer package to play the mpeg files stored on the CD.

There are two ways to handle audio CDs:

The basic steps in creating an MPEG layer 3 (MP3) file from an audio CD (using software from the NetBSD packages collection) are:

The resultant MP3 file can be played with any of the audio/gqmpeg, audio/maplay, audio/mpg123 or audio/splay packages.

The process of writing a CD consists of two steps: First, a "image" of the data must be generated, which can then be written to CD-R in a second step.

If you want to make a backup copy of one of your audio CDs, you can do so by extracting ("ripping") the audio tracks from the CD, and then writing them back to a blank CD. Of course this also works fine if you only extract single tracks from various CDs, creating your very own mix CD!

The steps involved are:

If you have converted all your audio CDs to MP3 and now want to make a mixed CD for your (e.g.) your car, you can do so by first converting the .mp3 files back to .wav format, then write them as a normal audio CD.

The steps involved here are:

To copy an audio CD while not introducing any pauses as mandated by the CDDA standard, you can use cdrdao for that:

# cdrdao read-cd --device /dev/rcd0d data.toc
# cdrdao write   --device /dev/rcd1d data.toc

If you have both a CD-R and a CD-ROM drive in your machine, you can copy a data CD with the following command:

# cdrecord dev=/dev/rcd1d /dev/rcd0d

Here the CD-ROM (cd0) contains the CD you want to copy, and the CD-R (cd1) contains the blank disk. Note that this only works with computer disks that contain some sort of data, it does not work with audio CDs! In practice you'll also want to add something like "speed=8" to make things a bit faster.

You can treat a CD-RW drive like a CD-R drive (see Section 13.11, “Using a CD-R writer with data CDs”) in NetBSD, creating images with mkisofs(8) and writing them on a CD-RW medium with cdrecord(8).

If you want to blank a CD-RW, you can do this with cdrecord's "blank" option:

# cdrecord dev=/dev/rcd0d blank=fast

There are several other ways to blank the CD-RW, call cdrecord(8) with "blank=help" for a list. See the cdrecord(8) man page for more information.

Currently, NetBSD supports ISO 9660 and UDF DVD media. Information about mounting ISO 9660 and UDF filesystems can be found in the mount_cd9660(8) and mount_udf(8) manual pages respectively. DVDs, DivX and many avi files be played with multimedia/ogle or multimedia/gmplayer.

For some hints on creating DVDs, see this postings about growisofs and this article about recording CDs and DVDs with NetBSD.

To create an ISO image and save the checksum do this:

# readcd dev=/dev/cd0d f=/tmp/cd.iso

Here is an alternative using dd(1):

# dd if=/dev/cd0d of=/tmp/cd.iso bs=2048

If the CD has errors you can recover the rest with this:

# dd if=/dev/cd0d of=/tmp/cd.iso bs=2048 conv=noerror

To create an ISO image from a mounted data CD first, mount the CD disk by:

# mount -t cd9660 -r /dev/cd0d /mnt/cdrom

Second, get the image:

# mkhybrid -v -l -J -R -o /tmp/my_cd.iso /mnt/cdrom/

You can read the volume data from an unmounted CD with this command:

# file -s /dev/cd0d

You can read the volume data from an ISO image with this command:

# isoinfo -d -i /tmp/my_cd.iso

You can get the unique disk number from an unmounted CD with this:

# cd-discid /dev/cd0d

You can read the table of contents of an unmounted CD with this command:

# cdrecord -v dev=/dev/cd0d -toc