Instructor: In this lesson,
we're going to talk about optical drives.
Now optical drives come in three main varieties,
CD, DVD, and BD.
CD stands for compact discs,
whereas DVD stands for Digital Versatile Discs,
and BD stands for Blu-ray discs.
Before streaming became popular,
most of us bought our music using CDs
and our movies using DVDs or Blu-ray discs.
Each of these three types are used for different things
based upon the amount of data they can store.
CDs are the oldest form, and they actually store the least.
A CD can store anywhere from 74 to 80 minutes of music,
which equates to 650 megabytes to 700 megabytes of data.
The difference is the larger storage volume CDs
actually write further out towards the edge of the disc
giving it a little bit more space to write
and, therefore, more data can be stored
even when you're using the same basic technology.
CDs work by using a reader to be able to read information
off of the disc, and that reader is based on a laser light.
When you're using a CD, you're actually reading that
using a longer wavelength using an infrared light.
Over time, that 700 megabyte limit was a real problem,
and so manufacturers created DVDs
to be able to store things like digital videos.
The problem is a CD couldn't store an entire two hour movie,
but the newer format, known as a DVD
or Digital Versatile Disc, could store an entire movie.
With a DVD, you can store 4.7 gigabytes or 8.4 gigabytes,
depending on whether you're using a standard DVD
or a dual-layer DVD.
With a dual-layer DVD, you get 8.4 gigabytes of space,
which is almost double what you get with a standard DVD
because it has two different layers
that's storing information so you can shove a lot more data
onto a single disc.
When using a DVD, you're going to be using a red laser light
to read the information, and it uses a medium wavelength.
As the technology started moving to shorter wavelengths,
we could store more data on a given disc.
So you'll notice with CDs, we had a long wavelength
and DVDs, we had a medium wavelength.
When we get to Blu-ray, we actually have a short wavelength,
and this is going to use a blue laser in order to read
the data off of the disc, which is why we call it Blu-ray.
Now a standard Blu-ray disc can hold 25 gigabytes of data
and a dual-layer Blu-ray disc can actually hold up to
50 gigabytes of data, which gives us a tremendous amount
of storage capability on a single disc.
This is why, as we move from DVDs,
which could have high definition video, into Blu-ray,
we could move into 4K formats being stored on these discs
because you could store so much more information
with a dual-layer Blu-ray
holding 10 times more data than a standard DVD.
When it comes to these discs,
whether you're using a CD, DVD, or Blu-ray,
they're going to come in three different types.
These are known as read-only or ROM, write-once or R,
and write-many or erasable, known as RW/RAM/RE.
When you look at a read-only disc like a CD-ROM,
a DVD-ROM, or a BD-ROM, you're going to be able
to only read information from the disc.
So if I go to the store and buy a music CD
from my favorite band, that is a CD-ROM.
I can't write information to the disc.
It was written by the band and their manufacturers.
I can only read from that disc.
If you have a CD player, it will only be able to read,
and it won't be able to write.
To be able to write, you'd need to have
writeable media and a writeable drive.
Similarly, if I go to the store and buy a DVD
of my favorite movie, that is a DVD-ROM.
I can only read from it.
And if I buy a 4K movie
or some of the larger video games out there,
these usually come on a BD-ROM or a Blu-ray-ROM.
Now the second type we have is what's known as write-once.
This is, essentially, like if I'm writing
on a piece of paper with permanent marker.
Once you write it down, you can never erase it.
That's the idea of a write-once device.
If you're using a write-once CD, we call this a CD-R.
If you're using a write-once DVD,
this is labeled as a DVD-R or a DVD+R.
And the difference between these two formats
is how the laser is going to write information
onto that particular disc,
but otherwise, they're fairly identical.
And then for Blu-ray discs, we call this a BD-R,
which, again, is a write-once type of device.
The third category we have is what's known as a write-many
type of device, also referred to as an erasable disc.
Now, if you're using a CD, we call this CD-RW,
which stands for CD-read/write.
This allows me to write things on there,
then erase those files and then put new files on there.
When you're dealing with DVDs, we actually have three
competing technologies, DVD-RW, DVD+RW,
and then one called DVD-RAM or R-A-M.
The DVD-RW versions are going to be very similar
to the way that we have a CD-RW version.
The DVD-RAM discs are similar to DVD-RW,
but they are in a different type of form factor
because these discs are typically housed in a cartridge
and it looks very similar to a backup tape.
And that's really what the main purpose of these was for
was to be used for backups of systems.
Instead of having to use tape backups,
you could write things to a DVD-RAM,
and whenever you wanted to rewrite that,
you could erase the entire disc
and write over it again with the next day's backups.
And then we have our Blu-ray disc.
With Blu-ray, we also have a write-many type of disc
that we call an erasable disc, and because of this,
they call this a BD-RE, which stands for record erasable.
And similar to a CD-RW or a DVD-RW,
it can write, erase, and then rewrite information
to a Blu-ray disc using a BD-RE.
The next thing we need to talk about
when it comes to optical drives
is how fast are these drives.
Well, when it comes to an optical drive,
when you purchase one, you're going to get it
based on its speed rating, and we call that an X-rating.
This is because when you look at the device,
it's going to tell you how fast it is as a multiplier.
For example, when the CD drives first came out,
they were 1X drives or just CD drives.
A 1X drive is how you'd normally listen to the music,
and this will be able to read at a speed
of 150 kilobytes per second, but over time,
that was really slow when we wanted to read
or write information to a CD,
so they started creating drives that were faster
when you were dealing with data.
When you're playing music,
it is still going to operate at a 1X speed,
but if you're not, and you're doing data stuff,
you can actually operate it at 2X, or 4X, or 16X, or 24X,
and we actually see this going
all the way up to about a 52X drive.
With a 52X drive,
you can take that 150 kilobytes per second,
multiply it by 52,
and that gives you 7,800 kilobytes per second
or 7.6 megabytes per second.
And that's generally the speed you're going to find
in a modern computer if it has a CD player in it.
The next one we have is DVDs.
And with DVDs, the 1X speed is measured
at 1.385 megabytes per second.
And, again, with the DVD,
you can see this rated as an X-rating,
so these days a typical DVD player is about a 24X-rating.
And that means that you'd have 1.385 megabytes per second
times 24, which equates to 33.24 megabytes per second.
This, as you could see, is much faster than our CD player
even though the CD player was at a 52X-rating
because DVDs can read so much more data
at one time even at a 1X speed.
And the final drive speed we need to cover
is for Blu-ray discs.
At 1X speed, you're going to see these operating
at 4.5 megabytes per second,
but a typical Blu-ray disc player these days
is going to operate at 8X speeds.
For 8X speeds, we would take that 4.5 megabytes per second,
multiply it by eight,
and we get a total of 36 megabytes per second,
which, again, is not super fast, but it is pretty good
when you're reading and writing from an optical device.
As you can see, any of these optical drives
are not going to be blazing fast when you're dealing with
something that is 36 megabytes per second
versus, say at a hard drive,
that can operate at 300 megabytes per second,
there really is no comparison here.
But, again, it's the removable nature of these discs
that makes them popular and really easy to transport
and sell for music and video companies.
Now the final thing we need to cover
when it comes to optical drives
is how would you install one?
Well, if you're going to install one into your system,
you need to have an open 5.25 inch internal bay
that will allow you to insert
one of these drives into that bay.
These devices will normally be connected
using SATA data and SATA power cables,
and that way you can connect it directly to your motherboard
like you would an internal hard drive.
The big difference here is that it is going to have a slot
that faces outward of the case
so you can insert or remove those discs as you need to.
If you don't have room for an internal CD, DVD,
or Blu-ray player, you can install one
using an external device with an enclosure.
There are a lot of portable CD, DVD, and Blu-ray players
and writers that you can buy that will connect
to your system using USB or USBC,
depending on the make and model that you purchase.
Now I know I just covered a lot of different numbers
for you in this lesson, and you're probably wondering
which of these do I have to memorize?
Well, the ones that I would memorize
would be the storage sizes for CDs, DVDs, and Blu-ray discs.
For CDs, remember it is 650 to 700 megabytes,
for DVDs, it's 4.7 gigabytes or 8.4 gigabytes
if you're using a dual-layer disc,
and for Blu-ray, it's going to be 25 gigabytes
or 50 gigabytes if you're using a dual-layer Blu-ray disc.
These are important numbers to keep in mind
because you may see a question like:
You have 17 gigabytes worth of data to back up,
which of the following discs should you use
to write that amount of information?
And you would have to choose either a Blu-ray disc
or a Blu-ray dual-layer disc to be able to fit
all of that data, and you wouldn't be able to do it
with just a CD, or a DVD, or dual-layer DVD,
so keep this in mind as you're studying for your exam.