Radschool

Newsletter

Vol 9

Page 4

Computers and stuff

Sam Houliston.

CD's

This article appeared in a recent C-NET newsletter. We thought it very informative, so we’ve reproduced it here.

To understand why variations in CD-R compatibility and reliability exist (i.e.-  why you end up with so many coasters), it helps to know a bit about the makeup of the media. CD-R media has four layers: an upper label/protective layer, a reflective layer, a photo reactive-dye layer, and a transparent plastic (polycarbonate) bottom layer, which protects the two middle layers. Your CD-R/RW drive writes data to these discs by firing a laser in a short burst to burn a hole in the dye layer. This hole is filled in by the metal in the reflective layer above it, which creates a bright spot that's read like a pit in a commercial CD (commercial CDs are pressed much like LPs used to be).

Silver and gold

The reflective and dye layers are the most important layers in the equation. The reflective layer can be gold, silver, or a combination of both. Gold is generally thought of as the most stable in the long run since it's the least reactive with dyes and, therefore, less prone to corrosion. However, there's also a good argument for silver, which was specified in the original standard because it's more reflective and, therefore, more easily read by players. Manufacturers also claim that dye formulas have been improved to the point where reactions with the reflective layer are no longer an issue.

Fool's gold

Buying a disc with real gold in it can be a challenge because you can't go simply on product labelling or even the colour of the disc. The packaging on some generic discs may use the word gold strictly as an advertising ploy. And disc colours can be deceptive. The upper layer can be any colour of the rainbow, and manufacturers have also recently taken to colouring the transparent bottom layer. Some discs, for instance, have a gold-coloured upper protective layer, yet they actually use a silver reflective layer.

How can you tell fool's gold from the real thing? If store personnel cannot confirm the truth for you, ask them if you can open a package and look at the disc. If you look very closely at the bottom layer, even through a colour, you should be able to see a warm glow to the disc that signals true gold inside. Comparing a gold disc to a silver disc makes it easier to see the difference. If you cannot perform any of these checks, your best bet is to research company Web sites for the specification, or you can just learn from experience by buying different brands and comparing them.

To dye for.

The photo reactive-dye layer comes in more variations than the reflective layer does. The original official CD standard called for TDK's Azo dye, which is dark blue. However, a number of other dyes, such as the lighter blue cyanine, have been developed and employed since--basically so that vendors don't have to pay each other royalties. Some dyes, such as phthalocyanine, are lighter than others and don't produce as distinct a variation in colour between burn marks and the unburned areas. This has been the traditional knock on common reflective/dye combinations such as gold/phthalocyanine. By and large, however, CD-ROM-drive manufacturers have learned to compensate for the differences in dyes. Some recorders do have more trouble recording on phthalocyanine, but the discs do have a reputation for lasting longer than cyanine ones.

Next issue—how to care for your CD’s

A number of DVD formats are vying for consumers' attention. Here’s what the codes mean.

DVDs can hold 4.7GB of data, seven times as much as recordable CDs.

The road to video nirvana, though, is paved with potholes. There are three competing standards, DVD+RW, DVD-RW and DVD-RAM, all vying for market supremacy, confusing compatibility issues and keeping prices high. Good luck

Adrian Heinrich finishes his recollections of his time at 10Sqn with the old Neppy, he says another experience not forgotten was encountered when refuelling. You filled the main tanks and while waiting for the fuel to settle in the outer main the tip tank was filled up, out at the end of the wing with nothing to hang onto except the earth plug and the fuel hose. As the tip tank got near full the extra weight would cause the landing gear strut on that side to suddenly compress a few inches but this translated to about two feet at the wing tip and even though you expected it, it always scared the hell out of you. I never fell off or dropped the fuel hose but I'm sure it must have happened.

The Neppie was also well known for the amount of oil each of the main piston engines used, anybody who has watched a Neppie start up would never forget the billowing clouds of smoke which belched out for about five minutes. After a long flight I remember topping up each engine oil tank of 75 gallons with 15 gallons of oil each side."

RAAF 80th Anniversary.

The recent reunion coincided with the RAAF’s 80th anniversary, which was held on Sunday the 1 April, 2001.  Most blokes and blokettes, though obviously suffering severely from the previous night’s activities, made the effort and joined the march through the streets of Brisbane to the RAAF memorial. The ceremony was arranged by the RAAF Association, and we thank them for inviting us to march and thanks also to the young blokes who carried and looked after our banner for the march and the ceremony. After the official part of the show ended, it was over the road for the unofficial bit and a dog’s hair to get well again.

During the march it was a little disappointing to see the best the RAAF could do to mark the occasion was to send one solitary old Caribou to do a fly over. The poor old thing did one east/west run over George St, over the heads of the marchers, then a run from South Brisbane, over the river, and away towards the Story Bridge. It was a pretty poor show to mark what was a well attended celebration (the Chief of Air Force officiated) and was all over in the blink of an eye. The least they could have done was to fly it in a stol configuration, with flap, gear and ramp door down, all making one helluva racket, but instead it was cleaned up and flying at cruise speed. Perhaps there were airspace restrictions, but we feel it could have been done a lot better. We did hear someone suggest that they probably had to pre-flight 10 to find a serviceable one….but we wouldn't repeat that….