To address your questions, first we will look at the external vs.
internal question. Internal drives will run on the IDE interface,
take up a drive bay within the case, and will require power from the
power supply. The IDE interface on most modern computers runs at
burst speeds of 66 or 100 megabits per second, with average data rates
as high as 66 megabits per second.
Ultra ATA 100 FAQ
However, this requires you to have an open 5.25" drive bay in your
computer; some modern cases do not have this. You will also need to
have power available from your power supply. DVD-R drives can consume
as much as 20 watts of power. If you already have several fans, hard
drives or other accessories, your power supply may not be able to
supply the extra power.
Pioneer DVR-105 specs:
Additionally, with an internal drive, you will either have to open the
case and install it yourself, which can be daunting if you haven't
done it before, or pay a shop to do the installation for you, which
adds to the cost.
External drives connect, as you note, via USB 2.0 or Firewire. The
advantages of this include not needing to open the case to install the
drive, external power supply, so you aren't taxing your PC power
supply, and ease of moving the drive from computer to computer.
However, the external drives do cost more money.
Regarding USB 2.0 versus Firewire, both will require your computer to
have the appropriate connector or add-on card. Many older computers
do not include USB 2.0 support, only supporting the USB 1.1
specification. Even new computers often do not include Firewire
support, requiring an add-on card to be installed. If your computer
does not come with USB 2.0 or Firewire, you will need to factor in the
cost of an add-on card.
Both USB and Firewire are serial communications protocols. Firewire
can communicate at 400 megabits per second. USB 1.1 communicates at
12 megabits per second peak, although real world transfer rates are
often slower. USB 2.0 communicates at 480 megabits per second.
Firewire can supply power to external peripherials, while USB 2.0
cannot. Realistically, external drives usually have their own power
supply and this becomes a moot point.
USB 2.0 is backward compatible with USB 1.1, so if you add a USB 2.0
card to your computer, you can also use the legacy USB 1.1
Firewire and USB 2.0 are not compatible, and use physically different
PC World Firewire vs USB 2.0 FAQ
Other than that, there is no signifigant difference between them. It
is simply a matter of which you already have on your computer
I hope this answers your question; if you need further information,
please ask for a clarification before rating this answer.
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