- — 01 July, 2002 12:57
- How CDs work
- Drive speeds: Write/Rewrite/Read
- Media types: CD/CDR/CDRW/DVD/DVDR
- Internal vs External
- Device interface
Mac users will probably need to restrict their research to USB, USB2 and FireWire drives, as SCSI, IDE and PCMCIA interfaces are pretty uncommon in Macintoshes. Windows and Linux users have a little more freedom when it comes to hardware interfaces supported, so the next issue to consider is software support for your drive.
Most drives will come bundled with software of some description. Given the huge range in burning software on the market, have a good look at what you're getting. Often, it can be worth spending a bit more on a burner that comes with a good package such as Nero (Windows) or Toast (Mac), rather than a cheaper model that comes with some unknown application that might give you grief.
Remember that there are two different ways of writing data to a CD. Firstly, there is the old fashioned way of creating a disk layout and then clicking the record button. While this is satisfactory in the majority of cases, there are times when you might like to be able to save documents onto a CD, just as you would with any other disk in your PC. To do this you need to use packet writing software such as DirectCD (Roxio) or InCD (Ahead). Packet writing software runs in the background and allows you to format CDs and use them as you would any other removable medium. If you want to be able to do this, you need a drive that supports packet writing. Also, bear in mind that this is really only effective with rewritable disks. Even though it is possible to use packet writing with a write-once CD, you may find that these will fill up quickly and may never reach their 650-700MB capacity- especially if you are overwriting the same file repeatedly.
<---cs:DVD/CDRW combo drives:cs--->
DVD/CDRW combo drives
For about the same price as buying a DVD drive and a CD Writer, you can buy a drive that is both. This may be worth considering if you plan to upgrade to a DVD drive in the future. Bear in mind that if you wind up with an IDE DVD reader and an IDE CD burner, your PC will only support two hard drives at the same time. This is due to the unfortunate fact that almost every motherboard ever made supports a maximum of four IDE devices, be they hard disks, ZIP drives, CD-ROMs or CD writers. So, buying a DVDR drive instead can free up room for a third hard drive. Alternatively, there is always the option to install your IDE burner into an external USB or FireWire box at some point down the track if this becomes an issue.
As DVD writers start appearing under the $1000 mark, and with prices rapidly dropping in DVD media, you may need to ask yourself whether it's worth holding out for or taking the plunge! A DVD writer will give you 4.7GB per DVDR disk rather than the mere 700MB that can be squeezed onto a CD. DVD writers will also burn regular CDs and rewritables, as well as reading video DVDs. Not a bad all-in-one solution if you can justify the expense. A blank DVD disk will cost about $10 - 15, which is a similar price per megabyte ratio to blank CDs.
|AT A GLANCE|
|Comparisons between DVD and CD standards and media|
|DVD-RW and DVD+RW||CD-RW|
|DVD-RAM||No CD format|
<---cs:Buffer Underrun Protection:cs--->
Buffer Underrun Protection
For a CD writer to do its job, a constant stream of data must be provided by the system so that the laser can write an uninterrupted session to the CD. Each CD writer will have a buffer memory, usually 2 or 4MB, which will iron out any fluctuations in the data stream. If this buffer empties for any reason- usually because you are using the computer for some other task while you are recording- then a buffer underrun error occurs and the CD is corrupted. Unless, that is, you have buffer underrun protection.
Until mid-2002, buffer underruns were a common problem, resulting in many CDs being recommissioned as drink coasters. The reason all this changed is because of a new technology developed by Sanyo, dubbed "Burn proof" (Buffer Under Run proof), which allows the record laser to be paused during a burn should the buffer become empty. Other buffer underrun protection is available under names such as "PowerRec" (Plextor), "ExacLink" (OAK), "SafeBurn" (Yamaha) and "JustLink" (Ricoh). The only thing to remember is that if a drive supports buffer underrun protection, the software used must also be compatible with your drive in order to utilise this feature- this is, fortunately, pretty standard. Theoretically, with buffer underrun protection enabled, you should be able to use your PC as per normal while burning, without having to worry about wasting any CDs.
MultiRead is an attempt to introduce a standard whereby drives with the widest compatibility for CD-based media can be identified. If you buy a drive that meets the MultiRead specification, you are guaranteed that it will support all CD, CDR, and CDRW disks. The MultiRead2 specification adds DVD and DVDR disks as well.
Traditionally, the 650MB/74min limit of CD media has gone hand-in-hand with CD writers being limited by their firmware or mechanics to the same capacity. A regular CD can actually store around 690MB/77min by utilising what is called the "lead-out" area of a disk. This process is called overburning, and requires software support in addition to the drive being capable of Disk at Once (DAO) mode.
Be warned, however, that not all drives support DAO or overburning and, in some cases, overburning can damage a drive! You may also find that some drives cannot read disks that have been overburned. A 700MB CD can be extended to 734MB or 83.5 minutes. While it is not a recommended procedure, it may be a point of issue for those hell bent on pushing their systems to the absolute maximum!
This may be a small consideration for most people, but if you are interested in using mini-CDs or business card style CDs, your CD writer's drive will need a groove for 8cm disks. The capacity of a mini-CD is about 185MB or 21 minutes. Some MP3 players require mini-CDs, so bear this in mind if you intend to buy one of these. A business card size CD will hold 20 to 60MB, depending on how much of the disk has been cut off.
Double density CD (Back to contents)
In 2000, Sony introduced their double density CD format that effectively doubled the capacity of a regular CD to 1.3GB. This format is referred to as DD-R and DD-RW for the rewritable version. This format is not widely available or supported, but it may be worth considering if you are not planning to distribute the disks you burn, and you think the extra capacity is necessary.
Unless you are tempted by DVDR drives or external CDR kits, you are more than likely looking at buying an IDE CDRW drive. If you are prepared to fork out some extra cash, you may decide to go with a 40x burner, although anywhere between 12x and 24x will probably do. Remember, the difference in speed between 24x and 40x equates to less that a minute and a half in burn time.
Check that the drive you buy supports buffer underrun protection, mini-CDs, and has MultiRead compatibility. Make sure you get some good bundled software, as well as a connector cable and warranty. Also check that your PC has at least one more IDE interface on your motherboard (i.e. less than four hard drives and/or CD-ROMs already installed). Otherwise, if you're going with an external, SCSI, USB, USB2 or FireWire drive, make sure your PC supports it or can support the upgrade required (e.g. an extra PCI card slot in the motherboard). Then, if you've made it this far, you should be burning in next to no time!