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Once the domain of the dedicated computer nerd, Compact Disc writers have finally fallen in price to a level that makes this remarkable bulk data storage technology affordable to anyone requiring safe and secure long-term data storage. Fitting neatly into a PC, in the same sized slot as a standard CD ROM drive, we put two market leading CD writers, Yamaha CDR100 quad speed, and the Hewlett Packard double speed to the test.
CD writers use a laser to burn data onto a photosensitive layer on special CD Recordable media. This emulates the pattern of tiny pits and bumps on a conventionally manufactured CD ROM. CD writers will also read CD ROM, although both the devices we tested displayed a reluctance to read their own CD's!
CD Recordable is a write once, read many times medium holding a staggering 650MB data, known in computing parlance as a WORM device. It is possible to record data in several sessions - but you loose 28 MB data space each time, and some early CD ROM drives can't handle multi-session CD's. However, single session CD's may be read on virtually any standard CD ROM drive.
With suitable software, CD Recordables will also record audio and video, and like their manufactured cousins, play from the inside to the outside. Since you really only have one shot at making the CD, you need to plan your CD in advance. Seasoned CD Recordable users suggest you reserve 650MB hard disk space to organise copies of your original files in a logical and meaningful order, before committing them to CD.
The importance of planning before cutting became apparent when we deployed CD Recordable to place three years worth of word-processed business letters, documents, photographs, slides and articles on a single disc. We found that a well-organised CD subsequently allows any reasonably computer-literate individual to replicate and retrieve huge pools of data on any reasonable quality PC, whereas a badly organised disc is almost useless.
Cutting a CD ROM is not a matter of simply transferring files from one disk drive to another. CD was originally designed as continuous data format - used for storing digital audio and video. Consequently, using a CD to store data files involves a certain amount of electronic trickery. A data CD holds all the files you want to store in one big file often called a raw data file. This tricks the CD into thinking it is holding a continuous digital audio track.
Usually CD writing software will create the raw file at the same time as the writer burns data to the CD. The trouble is that raw data has to be trickled slowly and continuously onto the CD Recordable. If the data flow is interrupted, if only for a few milliseconds, the CD Recordable is ruined.
To minimise this problem, CD writing software gives you the option of creating the raw file before you make the CD. This makes CD production much more reliable, but the temporary raw file can demand a further 650MB spare hard disk space.
Contrary to the impression one gets from various manufacturers' promotional literature, CD Recordables should be handled very carefully. They don't like strong sunlight. We placed two data-laden CD Recordables the south-facing window. After a week, just one was barely readable. After two weeks, data on both CD Recordables had been totally destroyed.
Physically, data is well protected from the playing surface by a millimetre of clear plastic. However, on the other side, the label sits directly on top of the data, and any damage to the label can result in a permanently damaged CD.
Writing CD's is a slow process, taking well over an hour for a full CD - if you cut at single speed. Both the devices we tested were unreliable when cutting at their maximum speeds. The Yamaha would work OK at double speed, whilst the Hewlett Packard would only perform properly at single speed.
A wide variety of devices boasting cutting speeds from single to quadruple are available for upwards of £270.00. Blank CDs cost upwards of £2.50 each and store 650MB data, or 74 minutes of high quality digital audio.
Make sure your supplier provides you with the correct CD writing software for your operating system. Some software will not work on Windows NT. Setting up CD writers can be tricky, and often it proves simpler to get your supplier to install and test it for you. To take maximum advantage of Recordable CD, you need a powerful dedicated Windows-based PC, fitted with a hard disk with at least 1.3GB free space and at least 32MB RAM.
A final word of caution: software manufacturers are becoming increasingly concerned about illegal copies of their programs being distributed on CD Recordable. Most CD Recordable media has embossed serial or batch numbers usually visible near the centre of the disc. In addition, CD writing software often encodes identification data on the disc. Consequently, perpetrators of dodgy CD's can usually be traced by sufficiently determined law enforcement agencies.
