Ask Rick Maybury 2014

  

 

Ask Rick 335 15/11/14

 

Building Rapport

I have now started using my Windows 7 laptop for Internet banking, and some online purchases. On the recommendation of my bank I have installed Trusteer Rapport. Does this provide adequate security, or would you recommend additional software?

Robert C Mawdsley, by email

 

Trusteer Rapport, now provided free by several major banks and financial institutions, is not a complete answer and you should continue to use your common sense, and conventional anti-virus and malware applications, but it does provide an extra layer of protection. It is particularly effective against Man In The Middle and phishing attacks – which attempt to intercept your login credentials -- and it detects, removes and keeps a running check on new malware strains. It is not without problems, though, and it can affect the performance of older and slower PCs and some Mac OS X users have reported difficulties but in general, anything that makes online banking safer has to be a good thing.

 

 

Upgrade Downside

I have a Samsung Galaxy Tab 2 10.1 tablet with Wi-Fi and 3g. It is not tied to any phone network and I have never received an update. I would like to upgrade to the newer version of Android and researching the Samsung mobile website shows that both O2 and Vodafone have released updates. I have an O2 Monthly contract SIM card; would it be possible to download and apply the O2 upgrade? Is there anything I should watch out for?

Roger Lane, by email

 

Installing a major operating system upgrade from an alternative source, which may be a customised version and not suitable for your particular device, is never a good idea, nor is installing it over a mobile broadband connection. Apart from anything else it could fail horribly if the battery gives out at a crucial point, and expensive, depending on your tariff and data allowance. The recommended method is to use your home broadband connection, and download and install the upgrade via your PC (or MAC), using Samsung’s Kies utility. This also takes care of the all-important backup, which you should carry out first, and recovery, just in case something goes wrong. There is a link to the free Kies download and a simple to follow tutorial on upgrades on the Samsung Support website at: http://goo.gl/AlGfkN.

 

 

LED Astray

I recently replaced over half of the light bulbs in my home with low power LED types. Mostly they work okay and the light they produce is vastly better than fluorescent bulbs plus the power savings, if true, seem impressive but some of them emit a dull glow when switched off. Is the glow cancelling the power savings and adding to my electricity bill? 

Peter Reeves, by email

 

The performance of LED light bulbs has improved exponentially in the past couple of years and given their long life expectancy, very low power consumption and rapidly falling prices, they are a cost effective alternative to tungsten and compact fluorescent (CFL) bulbs with payback times measured in months rather then years. I expect that we will be hearing more about them in future, particularly with regard to interference, but we will deal first with that mystery glow. This is due to induction and/or capacitance effects, with tiny currents leaking through and across cables in the lighting circuit. It is probably too small an amount to be registered by your meter but even if it is, it is unlikely to be costing you more than a few pence per year. Some makes and types of LED bulb appear to be more susceptible than others so swapping them around or changing brands may cure it. However, unless they are in a bedroom you might even argue that it is a useful feature, acting as a free, or very cheap night-light.

 

 

Laser Faze

I know how records and cassette tapes record and reproduce sound but I cannot understand how a coating of dye on a recordable CD can do the same. Presumably the laser changes the colour of the dye according to the signal received, but the range of possible colours seems unlikely to be able to record music accurately. Also, in the case of reusable CDs, how is the original coating restored accurately enough for the whole cycle to be repeated?

Keith Parsons, by email

 

It has nothing to do with changing colours; optical disc systems such as CD, DVD, Blu Ray etc, pre-recorded and recordable, are entirely digital in nature. Data on the disc is stored as a sequence of pulses or binary digits (bits), usually described as ones and zeros. The bits on a CD are actually billions of microscopic mirrors or ‘pits’, arranged in a continuous spiral pattern and during playback they are read by a low-power laser. Incidentally, to reduce the effects of errors during manufacture and recording the pits, and the gaps between them (called ‘lands’) do not represent individual bits of data; to cut a very long and complicated story short, binary one is indicated by the change from a pit to a land (or land to pit), and no change means binary zero.    

 

In a recordable CD (CD-R) the reflective spiral data track is covered by a transparent dye layer that becomes opaque when struck by a second, more powerful, laser in the CD deck’s read/write head. By switching the beam on and off at a fantastically high rate it creates the sequence of pits and lands that can be read just like a normal CD. Rewritable CDs work on a similar principle, except that there is no dye layer. Instead the reflective spiral is a polycrystalline material (an alloy of antimony, indium, silver and tellurium). When it is zapped by a powerful laser the exposed area heats up to a temperature of around 500 degrees centigrade whereupon it liquefies and changes to a non-reflective amorphous state. All this happens in a tiny fraction of a second, creating the pits and lands. To erase or reuse the disc the reflective layer is returned to its polycrystalline state by the laser, this time by heating it to 200 degrees C.     

 

---end---

© R. Maybury 2014 2710

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