CD/DVD disc formats

Your desktop or laptop PC obviously must have a CD/DVD writer/drive in order to be able to write data to recordable discs.

Each of the following is a different CD or DVD standard/format: CD-ROM, CD-R, CD-RW, DVD-ROM, DVD+R, DVD+R DL, DVD+RW DL, DVD-R DL, DVD-R, DVD+RW, DVD-RW and DVD-RAM. Only the CD-ROM and DVD-ROM standards are not recordable. -R and +R mean that the disc can be recorded to only once, and -RW and +RW mean that the disc is rewritable (can be written to hundreds or thousands of times). The DL stands for Dual Layer, which means that the disc has two recordable layers on the same side that doubles its capacity. If you need to know the capacity of a particular format immediately, enter a suitable search query in a search engine, such as: capacity dvd+r dl. The first link probably goes to a Wikipedia page devoted to that format.

DVD RAM discs are of a different type to the other DVD types of recordable disc, the structure of which is similar to hard-disk and floppy-disk technology, because the data is held in concentric sectors instead of a long spiral as is the case with an analog recording or any other type of DVD disc. DVD-RAM discs are accessed like a hard or floppy disks and usually without any special software, which the other types of DVD disc require. This makes them popular as a storage medium because if a disc is damaged the data is less likely to be lost.

A double-sided one layer disc has a capacity of 9.4GB –  the maximum capacity of a DVD-RAM disc. Data can be read, written to and erased repeatedly. The discs can be reused around 100,000 times, ten times more than any other type of re-writable disc. Programs can also be run from a disc not just copied, as is the case with the other CD/DVD formats that require programs to be copied to a computer’s hard disk or SSD before they can be run. To be used, a DVD writer must support the DVD-RAM format, which not the case with all DVD writers.

DVD RAM – http://en.wikipedia.org/wiki/DVD-RAM

CD/DVD drives allow software/data to be installed/copied from CD/DVD discs, or allow software/data to be written to and read from recordable CD/DVD discs. A CD/DVD writer can write data to the recordable disc formats that it supports and read data from the disc formats that it supports.

CD-ROM and DVD-ROM discs are not written (burned), they are pressed in the same way as vinyl records are. The ROM stands for Read-Only Memory, which means that the discs can only be read, not written to.

There are several recordable CD and DVD disc formats – CD-R, CD-RW, DVD-R, DVD+R, DVD-RW, DVD+RW, and DVD-RAM.

Note that a CD drive cannot read DVD discs, but most DVD drives can read both CD and DVD discs. CD-ROM and DVD-ROM drives can only read CDs or DVDs respectively. A CD-ROM drive cannot read DVD-ROM discs; a DVD-ROM drive is required. There are DVD writers (recorders) that can read from and write to all of the disc formats, but a CD writer can only write data to CD-R (record-once) discs, and CD-RW (recorded to many times) discs.

Whichever type of disc you choose to use (the write-once CD-R, DVD-R and DVD+R are are far more popular than the rewritable discs (CD-RW, DVD-RW, DVD+RW, and DVD-RAM), you should always buy brand-named discs that the manufacturer of the drive recommends for your PC’s CD/DVD writer/drive.

I have used write-once DVD-R discs since the standard’s early days. At first I bought cheap no-brand discs and paid the price for that – discs that I could not read only a few weeks after burning them. Then I switched to using brand-name discs – Verbatim, Maxell, Sony, TDK, Imation, Memorex, etc. – which I have been using for many years with very few problems. Verbatim is my preferred brand. I always use the record-once DVD-R discs not the re-recordable ones because the latter type tends not to work on a wide variety of computers and the DVD-R disc work on every computer that I have used them on. It’s also a good idea to keep a permanent record of what you burn. It is quite easy to format a disc containing data that you wanted to keep.

The difference in price between different makes of DVD writer is due to the build quality, although it is difficult to buy a bad a DVD-RW drive these days. Unless you are only looking at Blu-ray drives, then any optical DVD burner you buy is likely to be of good quality. However, if you want the best quality, you should be looking at drives made by Pioneer or Plextor. Drives of mid-range quality are Samsung, Sony, NEC. All of the makes of DVD writer have risen to a certain level of features and reasonable quality, probably due to the arrival of the Blu-ray optical-drive standard. That is, there is no innovation in DVD burners anymore, so they all are competing on pretty equal terms.

Quality, brand-name optical CDs and DVD discs (including Blu-ray discs) are probably still the best option for long-term storage of data. If the discs don’t have labels glued on to them and are stored in a dark place at normal residential heat and humidity levels, most estimates give them a minimum lifespan of 5 to 10 years. I have tested some 10-year-old CDs that worked 100%.

If the discs are kept in carefully controlled data-center or museum-quality storage conditions (in dark, dry, low-temperature conditions) the lifespan of recordable optical discs can be very much longer — from 30 to 100 years.

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