A cdrom is a COMPACT DISK, READ ONLY MEMORY (CD-ROM) disk. Its a laser disk
that hold digital information.
The amount of information it can hold is 650-700 MBytes.
A laser beam from the reading device reads this digital information from the
disk.
Now there are various types of cdroms.
ACD or AUDIO CD has data in binary form as all cdroms have but the data is
written so that simple cdrom audio players can read them and transform that
digital data into a analog sound or in other words MUSIC.
If for example you stick a cdrom with DATA on it and not music, some cdroms
can play what the data would sound like... that is a hiss not very pleasing
to the ears. (most cd players don't let you do this..... )
A computer cd player can read the CDAudio format and detects that it is an
AUDIO cd , and lists the TRACKS of the songs.
A computer cd player is far more flexible than a simple audio cdrom player
on a sound stereo. This is why it can read various kinds of disks while the
average cd player on your stereo can read ONLY audio cds.
A VCD is the same kind of disk, but the data is written in a different way.
The data also is VIDEO AND SOUND. Like we have stereo systems with
cd players that can play sound, there are VCD players that you connect with
your TV and watch VCDs. Let me note that this technology is FAR OLDER than
the DVD format and I will tell you the difference later. So we have another
appliance connected to your TV that transforms the data from the disk to
moving images and sound. But the companies that created those video players
said, why not make them play audio CDs too? And they did that so they could
sell them to more people.
Now the quality of the VCD was poor.... the image was blurry, so they made
the SVCD or SUPER VIDEO CD... that was like the VCD but had better quality
video inside. Now the new players connected to the TV could play audio CD's
VCD's AND SVCDs!
Computer cdroms players could handle all of those formats!
But advancement never stops so they made the DVD or DIGITAL VERSATILE DISK
(not digital video disk as many think).
This was a DIFFERENT disk altogether because the data was even more
COMPACTLY written than a CDROM. Although if you see them normally they LOOK
the same,
but if you had a microscope and looked at it you would see that the
information is more dense in the DVD than on the CDROM. That is why a DVD
can hold at least 4.7 GB
or 4700 MB of data while a cdrom could only hold 700mb max. But because this
disk was different you needed another kind of player!
So they rolled out the DVD players. When you bought a DVD player it was
backward compatible to all the various disks! That means it could play ACD
VCD SVCD and of course DVDs! But if you tried to stick a DVD into a VCD or
SVCD player it would NOT work.
The same thing happens when you stick a DVDrom into a CDROM player on your
PC. It cannot read it. So you have to get another device that CAN read those
new disks.
So all the disks are data, some of the data is sound, audio, or data from
programs. The data is formatted in special ways for each device to read. The
newer devices are backward compatible. And the most flexible devices are the
computer cd and dvd players. Because they can read all the audio video and
data disks.
To make things even more mixed up, about 10 years ago there where some big
disks called VIDEO DISKS that had the size of an LP record and you could
watch movies from them. That technology never really took off though.
--
......Creativity is intelligence having fun !.....;-)
For the ones reading technical replies, I would kindly request them to give
me their feedback with another post (in the same thread of course), so I
will know if my advice helped them or not.
Kenny S
www.talentgrid.com
www.computerboom.net