CDs & DVDs: Different Types of Disk Explained C 200 / 1 Don t Waste Money Buying the Wrong Type Find Out Which Disks Your PC Can Use! Your PC almost certainly has at least one CD/DVD drive. In its most basic terms, that s a drive you can insert circular, silver-coloured disks into, but this is where the complications begin! In this article, you ll learn which types of disk you should buy to avoid wasting money, and discover exactly what disks to use with your particular drive. Most CD/DVD drives support a variety of disks, there are over a dozen different types. Read on for all the important facts about working with CDs and DVDs. By Alan Harvey What s the Difference Between CDs and DVDs?... Look for these Logos to Discover Which Disks Your PC Can Use... Understanding the Logos Shown on Your Drive... Simple Answers to Common CD and DVD Questions... Windows All C 200 / 2 C 200 / 4 C 200 / 5 C 200 / 11 This article shows you how to:... Determine which types of disk you can use with your PC... Decide which type of disk to use in different situations 21
C 200 / 2 CDs have been used with computers since the 90s DVDs are a newer invention...... and are almost identical to look at A DVD can store much more data CDs and DVDs are technically very different What s the Difference Between CDs and DVDs? Originally known by their full name, compact discs, CDs have been around since the early 1980s, although for years they were used only for audio recordings as a replacement for vinyl LPs. Personal computers were rare things at that time, and it wasn t until the mid-90s that we began to use CDs for computer data. DVDs arrived in the late 1990s and were at first mainly used for films as an alternative to VHS video tapes. With home PCs becoming popular, it wasn t long before DVDs made the jump to the computing world. CDs and DVDs are almost identical to look at: they are 12 cm in diameter, shiny and silvercoloured. It s only by turning the disk over and looking at the labels and logos on the other side that you can tell whether you re holding a CD or a DVD. Although they look very similar, there are two fundamental differences between CDs and DVDs: How much data they can store. A CD can hold 650 or 700 MB. While this is a large amount (about 500 times as much as a floppy disk, for example), it s dwarfed by DVDs which can hold at least 4.7 GB, or the equivalent of about 7 CDs. The way the data is stored. As you can probably guess, if both types of disk are the same size, but one holds so much more data than the other, there must be some clever new method used to store data on a DVD that allows it all to fit. In fact, there are numerous 22
C 200 / 3 methods used, all different from CDs, and all slightly different from each other too. They have names like DVD-R, DVD+R and DVD- RAM, to mention just a few, and not surprisingly they lead to a lot of confusion! More differences: Disks you can read, record or rewrite An important thing to consider about both CDs and DVDs is how they can be used. There are three different types of disk you can buy readonly disks, recordable disks, and rewritable disks: Read-only disks: a CD or DVD that already has information stored on it when you buy it. This may be a music CD, a DVD video, or a disk containing software to install on your PC. You can play or use these disks as often as you like, but you can t delete their contents or add anything new to them. Recordable disks: a blank disk, usually sold in packs of 5 or 10 (for DVDs) or up to 50 (for CDs). A recordable disk allows you to store data on it just once. After that, you can read the data you stored as often as you like, but you can t delete it or add anything new to the disk. Rewritable disks: also a blank disk, but it has one important difference from the recordable disk: you can erase one of these disks, deleting everything it contains, and use it again. Because these are more useful than recordable disks, they tend to cost a little more. Your PC must have a CD/DVD drive To be able to use CDs or DVDs, your computer must have a suitable drive. As the disks look almost identical, the drives you insert them into look similar too: they have a button you push to You can store data on a blank disk...... and perhaps erase the disk to use it again The drive always looks the same 23
C 200 / 4 It s hard to know the capabilities of the drive Check the logos on the drive make a tray slide out, you place the disk on the tray (usually label-side-up), and then you press the same button again to slide the tray back into the unit. Unfortunately, this only adds to the confusion! While it s easy to tell whether your computer has a drive fitting this description, that doesn t tell you what this drive can do. Will it work with DVDs or just CDs? Does it let you use recordable and rewritable disks? If so, does that apply to CDs and DVDs, or just one or the other? If it does work with DVDs, which of the many types of DVD can you use? Look for these Logos to Discover Which Disks Your PC Can Use The trick to finding out which types of disk you can use in your CD/DVD drive is fairly straightforward: have a look at the front of the drive (usually just below the slide-out tray) and you ll see one or more logos, as indicated in the screenshot below. These logos denote the different types of disk that can be used in the drive. These logos indicate the types of disk you can use Unfortunately, these logos don t spell things out as clearly as they should. Worse still, they don t match what you ll see on the packaging when you go into your computer store to buy disks! Nevertheless, these logos are your starting point. Compare the logos you see on your drive 24
C 200 / 5 with the logos pictured and explained in the next section of this article, and you ll know exactly what disks to look for when you go shopping and how you can use the different types of disk. Understanding the Logos Shown on Your Drive You can use the pages that follow in two ways. First, you can look at the logos to find the ones that appear on your CD/DVD drive. Second, if you ve turned to this article to find out what a DVD+RW or a DVD-R DL is, you ll find details here. We ll run through them in a logical way, starting with CDs, following with the general types of DVD, and then the very recent and more advanced types of DVD. Audio CD and CD-ROM The drive can read compact disks, but you cannot use blank CDs or any type of DVD. This means that you can play audio CDs and use CDs containing computer software (known as CD-ROMs). CD-R As well as reading audio CDs and CD-ROMs, this drive lets you store data on a blank recordable CD, but you can t erase the disk to use it again. Look for disks marked as CD-R (not to be confused with CD-RW ). This type of disk can hold at least 650 MB of files but most blank CDs can now hold 700 MB and there are a few brands that can hold Find out what disks your drive can use Play CDs and read CD-ROMs Recordable CDs 25
C 200 / 6 more still: this will be marked on their packaging. Spoken out loud, you d refer to this by the three letters CDR. Rewritable CDs Play DVDs and read DVD-ROMs CD-RW This drive can use any type of CD. It can read audio CDs and CD-ROMs, it can use CD-R disks described above, and it can use rewritable CDs which will have CD-RW on their packaging. Unless your drive is more than about 8 years old, it should have this logo rather than either of the two above (and possibly has one or more DVD logos too). You d refer to this disk out loud as a CDRW. Basic DVD and DVD-ROM This is the basic DVD logo indicating that your drive can play at least some types of DVD. If nothing is written under this logo, you can assume that the drive will play films bought on DVD as well as DVDs containing computer files (known as DVD-ROMs), but it can t be used with any type of blank DVD. However you may see combinations of R, RW and RAM beneath this logo signifying that one or more of the recordable/rewritable types of DVD can also be used. For example, if you see R/RAM written 26
C 200 / 7 below the logo, you can use DVD- R and DVD-RAM disks with it too (explained below). DVD-R As well as reading basic DVDs and DVD-ROMs, this drive lets you store data on a blank recordable disk marked as a DVD-R, but this type of disk cannot be erased and reused. A disk can hold 4.7 GB. When buying disks, make sure the disks are marked DVD-R and not DVD+R (unless your drive also works with DVD+R disks). You d refer to this disk as a DVD minus R when asking for one. DVD-RW This drive can read ordinary DVDs and you can use blank recordable DVD-R disks. You can also use rewritable disks marked DVD-RW which can be erased and reused. A disk can hold 4.7 GB. Again, make sure you re not buying DVD+RW disks (unless your drive also works with DVD+RWs). To refer to this disk out loud you d say DVD minus RW. DVD-RAM As well as reading basic DVDs and DVD-ROMs, this drive can use blank disks marked as DVD-RAM. Recordable DVDs using the minus format Rewritable DVDs using the minus format Rewritable DVDs using the RAM format 27
C 200 / 8 A drive that supports the minus and RAM formats Recordable DVDs using the plus format These are rewritable disks which can hold up to 4.7 GB. You d refer to this type of disk out loud as a DVD ram. DVD Multi You may see this logo on your drive, but it doesn t relate to one particular type of disk. Instead, it means the drive can read basic DVD-ROM disks, and can also read DVD-R, DVD-RW and DVD-RAM disks. If you see the word Recorder below this logo, the drive can be used to store data on to those types of disk as well. If the word Recorder doesn t appear, it s likely that the drive won t let you store data on the disk, but can only read disks that have had data stored on them by another drive. DVD+R As well as reading basic DVDs and DVD-ROMs, this drive lets you store data on a blank recordable disk marked as a DVD+R, but this type of disk cannot be erased and reused. A disk can hold 4.7 GB. When buying disks, make sure the disks are marked DVD+R and not DVD-R (unless your drive also works with DVD-R disks). Spoken out loud, you d refer to this as a DVD plus R. 28
C 200 / 9 DVD+RW This drive can read ordinary DVDs and you can use blank recordable DVD+R disks. You can also use rewritable disks marked DVD+RW which can be erased and reused. A disk can hold 4.7 GB. Again, make sure you re not buying DVD-RW disks (unless your drive also works with DVD-RWs). You d refer to this disk as a DVD plus RW when asking for one. DVD+R DL and DVD+RW DL If your drive is fairly new you may see the letters DL included alongside the reference to +R or +RW, and they stand for Dual Layer or Double Layer. With this drive, you can use the same disks as you would with a DVD+RW drive (mentioned above). You can alternatively buy special Dual Layer disks to use in this drive: they cost more, but they can hold up to 8.5 GB. If the logo says DVD+R DL, look for disks marked the same way and bear in mind that these are recordable disks which can only be used once. If the logo says DVD+RW DL, look for disks that say the same on their packaging, and you ll also be able to erase and reuse these disks. Rewritable DVDs using the plus format The letters DL mean you can use dual layer disks for extra storage capacity 29
C 200 / 10 Two new types of disk and drive In general, DVDs can hold 4.7 GB BD-R and BD-RE Blu-ray Disc is a very new type of disk which can hold up to 25 GB (about 6 times the capacity of an ordinary DVD). The BD-R disks are recordable, and BD- RE disks are rewritable. The drives and disks are still rare, and most of the current Blu-ray drives can only read the disks. HD DVD-R and HD DVD-RAM HD DVD is another new and rare type of disk. The HD DVD-R disks are recordable and can hold 30 GB; the HD DVD-RAM disks are rewritable and can hold 20 GB. You probably don t have a drive that can play Blu-ray or HD DVD disks, but these two are fighting between themselves to take over from DVD. It s rather like the battle for supremacy between VHS and Betamax in the early days of video recorders, and everyone hopes there will be one clear winner. Unfortunately, it seems at the moment that both might become popular, so that the confusion about what we should use carries on for another few years! Squeeze Even More Data onto a DVD: Double-sided and Dual Layer Disks There are three basic types of DVD which are DVD-R, DVD+R and DVD-RAM. In addition there are DVD-RW and DVD+RW which are rewritable versions of the first two types. Any of these will hold about 4.7 GB of data, which is an awful lot: it s enough to hold over 1000 ultrahigh-quality digital photos, or 1 1 2 million pages of 30
C 200 / 11 text. If that s not enough, buying another disk is an easy and cheap option. However, there are two other options. One is to buy double-sided DVDs. These work rather like cassette tapes, in that when one side is full you turn the disk over and store more data on the other side. This lets you store a total of just under 9 GB on a single disk. The more recent option, mentioned in the section above, is the Dual Layer disk. If your drive can work with Dual Layer (or DL ) disks, you can store about 8 1 2 GB and you don t turn the disk over: instead, the drive stores the data on two separate layers, one deeper into the disk than the other. Simple Answers to Common CD and DVD Questions It s important to know which types of disk you can use in your drive, for the obvious reason that you won t buy the wrong type. However, that will still leave you with some choices to make. To start with, you may be able to choose between using a CD or a DVD; you can choose between using a recordable ( R ) disk or a rewritable ( RW ) disk; and you may be able to choose between the three different types of DVD (+R, -R and RAM). Let s try to sort out some of those choices: Should I use a CD or a DVD? It largely depends on how much data you want to store. If you re putting a large number of files on a disk and they won t all fit on a CD, you might choose to use a DVD in order to keep them all together, but you could also use several CDs. If the disk is just to be used in your own PC, this decision is no more complicated than that. Double-sided DVDs give twice as much storage Dual Layer disks are a neater option Your drive may support various different types of disk You can fit much more on one DVD 31
C 200 / 12 If you want to give the disk to someone else so that they can use it in their PC, you must consider whether they have a DVD drive. If they don t, use CDs. If they do, make sure their drive can read the type of DVD you re planning to use (I ll explain that a little later). Should I use a recordable or a rewritable disk? Rewritable disks are usually best Most drives support two or more types of DVD As a rule of thumb, rewritable disks are better because you can erase them and use them for something else when you no longer need the original data you stored on them. There are a few cases in which a recordable disk is the better choice though: To store files you want to keep permanently without risk of accidentally erasing the disk. To make a music CD that you can play in a home or car stereo, because these can t usually read rewritable disks. To give files to another computer user, because their CD/DVD drive may not be able to read the rewritable disks you create, but it will usually read recordable disks. One of the great things about CDs is that the only choice you have to make is whether to use a recordable (CD-R) disk or a rewritable (CD-RW) disk. With CDs you don t have the three different plus, minus and RAM types that make DVDs so confusing, and there are no such things as doublesided CDs or dual layer CDs. Which type of DVD should I use? If your drive can work with DVDs at all, it isn t unusual to find that you can use several different types of recordable or rewritable DVD. Your drive may be able to cope with DVD-R and DVD+R, and 32
C 200 / 13 perhaps DVD-RAM as well. If you can choose between two or even all three of these, which do you pick? If the disk is just to be used in your own PC, it really doesn t matter. DVD-RAM is said to be the most reliable of the three, but it s quite reasonable to make this decision based on the prices of the disks. If you want to give the disk to someone else, so that they can use it in their own PC, you need to pick a type you have in common. For example, if your drive can record data on to a DVD+R and their drive can read a DVD+R, that s a suitable choice. Similarly, if your drive can record on to dual layer disks, make sure your friend s drive can read dual layer disks before using them. Otherwise, use the ordinary (and cheaper) single layer disks. Pick a type that suits everyone who will use the disk Rewritable disks don t always travel well between one device and another, so it s best to avoid using them to share files with someone else. There s no risk to the disks or the data on them, but you may just find that the other machine won t read them. Even if your drive and your friend s drive both claim to support DVD+RW disks, for example, it s best to use the recordable DVD+R disks. The same is true if you want to use the disk in a portable DVD player or a home-entertainment DVD player. This player should have similar logos to tell you which types of DVD it can read, and you need to find a type that both devices have in common. Using the Correct Types of Disk in Windows Vista and XP CDs and DVDs are different from most other types of disk in one important respect: you must Special software is needed to put files on CDs or DVDs 33
C 200 / 14 These programs provide all the features you need...... but Vista/XP can do a certain amount for you use special software to copy files to a CD or a DVD. If you re writing a document or making adjustments to a photo and you decide to save the result, you can save it immediately to your hard disk, a floppy disk or almost anything else, but not to a CD or DVD. Instead you have to save the file to your hard disk, and then use the special software to copy it to CD/DVD. There are a great many programs available for this. They are referred to as CD burning or DVD burning programs, and well-known examples are Roxio Easy Media Creator and Nero. Most of these are fully-fledged, professional programs which can cope with any type of CD or DVD that your drive can work with, and they provide features to do almost anything you can imagine with a CD or a DVD. If you use Windows Vista or XP, you may be able to avoid buying one of these programs. Both Vista and, to a lesser extent, XP have the ability to copy files to your CD/DVD drive, but they provide only the most basic features: Windows XP can copy files to a CD-R or a CD-RW disk, and it can also erase a CD-RW disk you want to use again. It can t copy files to any type of DVD, so you would need to use a special program in XP to make DVDs. Windows Vista is much more capable: as well as CD-R and CD-RW disks, you can use DVD-R, DVD-RW, DVD+R, DVD+RW and DVD-RAM disks without resorting to a separate program, and it can even cope with Dual Layer disks. 34