I type in:
mount /dev/sda2 /mnt/dvd

But this comes out:
mount: you must specify the filesystem type

The output of lsblk is:

sda      8:0    0 149.1G  0 disk 

├─sda1   8:1    0 145.1G  0 part /

├─sda2   8:2    0     1K  0 part 

└─sda5   8:5    0     4G  0 part [SWAP]

sr0     11:0    1   2.2G  0 rom 

I can only assume that your DVD is a internal one with Master/slave jumpers set right in
Bios so the hardware is readable for Kernel or the system to be able to access its contents. Hard-disk usually master and other peripheral-devices like cd/dvd usually are slaves.

One way to find where your Cd/Dvd is listed mounted is to insert a cd/dvd in and open up your files in a file reader like nautilus or nemo or what ever is currently installed in your system or just click icon for Files.
Hoover over your Devices currently showing with your mouse pointer. If nothing shows up for your CD/Dvd when hoovering over your mouse over Devices when you have a cd/dvd disk in. If it did show up and your mouse is over the listed device will show you the path ex. Media / (computer or user name ) / Current label of the cd/dvd name.
You can go in to that folder and read what drive letter is assigned for your cd/dvd drive. Ex.cdrom0 or a other number for it so you can mount it permanently to the system.

Another way to do it is simply browse through the subfolders in /media (or could even be /mnt on older systems) until you find the one that shows your disc (you’ll need to have one in the drive, of course).

Or if you want to do it via the terminal, you can use
mount|grep ^'/dev'

which will display info as follows: This is just a Ex.
/dev/sda2 on / type ext3 (rw,relatime,errors=remount-ro)
/dev/sda1 on /media/Windows-XP-x64 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096)
/dev/sr0 on /media/cdrom0 type iso9660 (ro,nosuid,nodev,user=ozzman)

As you see your Cd/dvd listed in that folder you can open that folder by owning root privligies for your file reader so you can modify it in your file system to make it be visible every time you boot up by modifying the mount point or do the following in terminal.

[Ubuntu] Mount/Unmount CD/DVD
in command line
To mount your CD/DVD:
Open a terminal ctrl+alt+t and type
sudo mount /media/cdrom0/ -o unhide
To unmount your CD/DVD:
Open a terminal and type:
sudo umount /media/cdrom0/ -l
Assuming that media/cdrom0 is the location of your CD/DVD rom.

That should mount your cd/dvd player to be part of your system when booting up.

If not can you repost here again.

How to mount cdrom in Linux

1. Detecting CD/DVD-ROM drives


2. Creating mount point


3. Mount CDROM


4. Mounting Audio CD's


5. Allowing users to mount CDROM


6. Umount and eject CDROM


7. Troubleshooting
   7.1. Testing for ISO9660 support
   CD's and DVDs are using ISO9660 filesystem. The aim of ISO9660 is to provide a data exchange standard between various operating systems. As a result any Linux operating system is capable of handling the ISO9660 file system. This guide describes a way on how to mount / umount ISO9660 file-system in Linux and thus enabling user to read data from CD or DVD media.*

If you still have some questions after reading this article please try our new LinuxCareer Forum.

1. Detecting CD/DVD-ROM drives
   At first we need to find usable devices capable reading ISO9660 data. In other words we need to find CD/DVD drives available on our Linux system. In order to do that, we can use "wodim" command and its --devices option. wodim will scan and output symbolic device names found in /dev/* directory:

wodim --devices

If a wodim command is not available on your system make sure cdrecord package is installed on your system.

Debian and Ubuntu:

Sudo apt-get install cdrecord

RedHat, Fedora, CentOS:

yum install cdrecord

Once you execute wodim command and you have some CD/DVD device hardware available in your system you should see an output similar to the one below:

$ wodim --devices

>wodim: Overview of accessible drives (1 found) :

0 dev='/dev/scd0' rwrw-- : 'TSSTcorp' 'CD/DVDW SH-S183L'

From the above output we can determine that our CDROM / DVDROM drive can be accessed at the symbolic location /dev/scd0.

Furthermore, it needs to be mentioned that different systems may behave differently. For example in Debian Linux a user running wodim command must belong to cdrom group, otherwise the wodim command will fail with an error message similar to the one below:

wodim: No such file or directory.
Cannot open SCSI driver!
For possible targets try 'wodim --devices'
or 'wodim -scanbus'.
For possible transport specifiers try 'wodim
dev=help'.
For IDE/ATAPI devices configuration,
see the file README.ATAPI.setup from
the wodim documentation.
2. Creating mount point
Your Linux system may already have created a mount point for you, it is usually something like /cdrom, /media/cdrom, /media/cdrom0 or /mnt/cdrom . If this is not your case, feel free to create your own mount point. To have mount point available is a absolute must! Mount point will represent a place from where data located on CD or DVD will be made accessible to the user.

sudo mkdir /media/cdrom

1. Mount CDROM
   If you do not belong into cd-rom group and thus do not posses permissions to mount CD-ROM, switch to root user #sudo -i and execute a command below:

sudo mount -t iso9660 /dev/scd0 /media/cdrom

mount: block device /dev/sr0 is write-protected, mounting read-only
your CDROM is now mounted and accessible from /media/cdrom directory. At this point simply navigate to this directory to access your data.

1. Mounting Audio CD's
   Sometimes you would like to listen to your favorite music and when you try mount music cd with a command above you can get problems like:

linuxcareer.com

mount -t iso9660 /dev/hdc /media/cdrom0/

mount: block device /dev/hdc is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/hdc,
missing codepage or other error
In some cases useful info is found in syslog - try
dmesg | tail or so

linuxcareer.com#

This is because music CD's does not contain standard iso9660 filesystem as such. In fact the story with music CD-ROMs is easier as it is with data CD-ROMs using iso9660 filesystem.

In order to listen to a music CD all what needs to be done is to insert music CD ( Compact Dics ) into CD-ROM/DVD-ROM drive and fire up you favorite music CD player. The only thing you may need to be concerned about is whether "kdemultimedia-kio-plugins" package for KDE or "gnome-media" package for gnome window manager are installed. Those packages allow you to listen to music CD content.

In case you would like to see a content of your music CD or perhaps convert some music trakcs to MP3 / OGG format just start "KONQUEROR" and enter location:

audiocd:/
into Konqueror's navigation bar.

1. Allowing users to mount CD-ROM
   You can also allow users on the system mount CD's or DVD's. To do that edit your /etc/fstab file and add line similar to the one below:

/dev/sdc0 /media/cdrom0 iso9660 ro,user,noauto 0 0

1. Umount and eject CDROM
   There are couple ways how to remove/unmount CDROM.

unmount /dev/hdc

eject

or you can simply run:

eject

If you are unable to unmount your previously mounted CD-ROM, make sure that you are not in the directory where your CD-ROM is mounted or that some other application is not using it.

If you are still having problems to unmount your CD-ROM medium you can use fuser command to kill all related processes using your device.

fuser -mk /dev/hdc

eject

NOTE: Never use the above command on devices mounted read/write unless you are sure what you are doing.

1. Troubleshooting

7.1. Testing for ISO9660 support
Although it is highly unlikely that your system does not support this specific filesystem here are some tips on how to test for ISO9660 presence in your Linux system.

In case you face some troubles try to search for loaded kernel modules with lsmod command or by reading a content of /proc/filesystem file:

cat /proc/filesystems | grep iso9660

or

lsmode | grep iso9660

The actual module is be a part of libiso9660 package. Both commands should report available ISO9660 filesystem.