CD-ROM, DVD

CD-ROM disks are very common and conform to a standard. They are removable and can hold about 640MB. They are also cheap to make.
Howevr, they are usually read-only. You cannot to one standard.
For this reason they are not very common.

CD_cd rom

Now there are different types of cd-rom.

We have:

cd-rom rd (read only memory). Capacity from 700mb to 800mb

cd.rom rw (rewriteble). Capacity from 700 mb to 800mb.

Dvd-rom rd (read only memory). Capacity from 2gb to 8gb

Dvd-rom rw (rewriteble).capacity from 4,7gb to.