Choosing Step 6
Optical Drive
Introduction
Choosing an optical drive is relatively simple. Currently there are 2 types of disk that are worth consideration; DVD and Blue-Ray. There are drives available for each format which can either read only (ROM), or read and write disks (RW). A DVD can hold up to 8.5GB on a dual layer disk, while a Blue-Ray disk can hold up to 50GB of data also on a Dual layer disk.
DVD has been around for so long that it would be unusual not to want some form of DVD drive on your PC. Given the very cheap price of DVD writers, it seems like the most suitable choice for most users. Some may also wish to have a DVD-ROM for secondary reading and direct copying of disks.
Blue-Ray on the other hand is relatively new and for most users will not hold much value. Two situations when a blue-ray drive would be appropriate are firstly for a Media Centre PC where playing high definition Blue-Ray disks would be desirable and secondly where backup or distribution of very large files is important. Remember that if you wish to play Blue-Ray movies then you will need a graphics card and display that are 'HDCP' compliant. HDCP is the mechanism that Blue-Ray uses to ensure copy-righted disks are not copied.
Other factors to consider are the speed at which you wish the drive to read and/or write data at and the type of connection it uses.
Examples
Budget PC
Our budget PC cannot afford any fancy BluRay drives so we'll stick with a simple DVD-RW should be fine for most users. We could save another £5 by buying a DVD-ROM, but for the benefits that a DVD-RW brings it seems like a bad choice.
Home PC
Gaming PC
Currently there are no games available on Blue-Ray disks and it doesn't look likely that there will be for a few years yet so well save the money for our other components and just get a trusty DVD-RW drive for all our examples.
Media Centre PC
our Media Centre will almost certainly want a Blue-Ray drive for playing HD movies. A Blue-Ray writer would also be useful for copying recorded television and films onto when Hard Disk space is low. However our lowest example will still use a basic DVD-RW to save costs.
Workstation PC
For our workstation, large files are very common so a Blue-Ray Writer will probably be of use for backup and authoring purposes.
Explanations
Read-Only (ROM) and Re-Writer (RW)
Drives that carry the word ROM (e.g. DVD-ROM) are Read Only Memory, which means then cannot write information onto a disk, only read it. Drives with RW in their title (e.g. DVD-RW) can both read and write disks.
DVD+ and DVD-
At the start of the DVD revolution, two types of writable DVDs emerged, DVD+ and DVD-. Both had their pros and cons and ultimately none won out over the other and both now provide almost identical functionality. Every DVD-RW drive available today will support both these formats, so really this is something you don't even need to think about.
Dual Layer
Dual layer (DL) DVDs and Blue-Ray disks are essentially a disk with 2 layers, giving that disk twice the capacity of a single layer disk. So whereas a single layer DVD can hold 4.3GB of data, a dual layer can hold 8.5GB. Likewise a single layer Blue-Ray can hold 25GB while a dual layer can hold 50GB.
Connections (SATA or IDE)
Blue-Ray drives are only available with a SATA connection. DVD drives on the other hand are available with either SATA or IDE (also known as ATA or Parallel ATA) connections. Although SATA is the newer type of connection, even the fastest DVD drives cannot get close to IDEs 133MB/s transfer ceiling and so there is no real performance difference between a SATA DVD drive and an IDE one. You may also find that you have problems installing older operating systems (windows XP for example) with SATA drives. For these reasons we would recommend buying an IDE DVD drive.
Speed
The speed at which an optical drive runs denotes how much information can be transferred to and from the disk. Playing a DVD movie requires a 1x DVD which is 1.32MB/s, so a 16x DVD drive can transfer information at 16 x 1.32 = 21.12MB/s. Blue-Ray has a 1x of 4.5MB/s, so a 4x BD drive will be able to transfer information at 18MB/s.
External Drives
External drives are available in both DVD and Blue-Ray format. These drives connect via USB in the same way an external hard drive would. They provide the same functionality as internal drives and can be plugged in and out while the computer is on. It‘s worth remembering you may have trouble installing older operating systems such as windows XP from one these drives so we would always recommend having an internal drive as well.
Lightscribe
'Lightscribe' is a technology incorporated into some DVD-RW drives which allows you to 'burn' a label onto the top of a disk. It can be an effective way of labelling disks neatly, though it does require 'lightscribe' disks in order to work.
Related Links
Trusted Reviews: StorageGood source for non-technical reviews and news of storage drives, including a few benchmarks.
Wikipedia: Optical DriveOptical Drive history and technical explanation of operation, design and implementation.
