Here Is Probably The Ultimate "No-brainer"...

Sunday 21st February 2010

The Government is even running a poster campaign to publicise it, but just for once they are right!

Everyone remembers learning in school physics lessons how heat rises. As a result, a large proportion of that expensive heating we use in our homes during the winter rises upwards through the house, into the loft - and straight out through the roof.  Great for the pigeons, but certainly not for our wallets.

Until the 1973 Middle East Yom Kippur War, also known as the "Six-Day War", energy was relatively cheap and loft insulation was not generally considered worthwhile.  Afterwards, crude oil prices soared and a 25mm (1") layer was recommended. As energy costs continued to rise, so did the recommended thickness.  Currently, it stands at 200mm (8"). Fortunately, the cost of loft insulation has tunbled, almost beyond belief.  This is partly due to Government subsidy, but also to the ready availability of a cheap raw material from which to make it.

The best loft insulation has always been glass-fibre.  Since glass bottles and jars etc. are now collected for recycling, rather than being dumped in landfill, there is a vast amount of scrap glass available.  However, most of it is a mixture of different colours and is thus of little use where clear glass is required, which unfortunately accounts for most packaging applications.  For loft insulation, on the other hand, all that matters is its thermal insulation properties and its visual appearance is entirely irrelevant.

At one time, glass fibre loft insulation had a well-deserved reputation as "bulk itching powder".  A facemask, goggles, gloves and old clothes were essential when installing it.  Indeed, it was usually necessary to throw the clothes away afterwards.  Modern technology, in addition to producing amuch cheaper product, has also made it much more user-friendly.

It is still sensible to wear a facemask, goggle and gloves, but the clothes can now be washed and the insulation can be handled without itching-related problems.  A shower or hot bath is still necessary afterwards, of course!

The "No-brainer"?  B&Q are selling triple packs of 200mm own-brand loft insulation for £5.  That's right, £5 for three rolls, not £5 each.  A typical loft will need about 8 triple packs, costing £40 in all.  Adding on £10 for a facemask, goggles and gloves gives a total cost of £50.  The annual saving at today's enegry costs is reckoned to be over £150!  It is a well-known saying that there are two certainties in life - death and
taxation.  Perhaps a third should be added - energy costs will continue to rise and rise!

The Numbers Game, As Applied To IT

Sunday 14th February 2010

Be prepared - there are some very large numbers coming along in the not-too-distant future

Manufacturers' marketing departments always like to parade numbers in front of would-be customers.  It may be a boast that their new laptop is "only" 20mm thick or that its battery lasts for 6 hours.  Sometimes, they will claim to have the largest/smallest/fastest/slowest/etc "whatsit" and wheel on a few numbers to justify the claim.  For really large numbers, however, 64-bit operating systems take some beating.

The universally-popular search engine Google derives its name from a rather bad pun on "Googolhedron", a 3-dimensional mathematical shape (or polyhedron) with 10^100 facets.  Were it possible to make such an object, it would look like a sphere with an apparently smooth surface, because each facet would be so small.

Although the googolhedron is the clear winner in the numbers game, a 64-bit operating system can at least finish a distant second.  The maximum amount of memory any operating system can address directly is govderned by the number of bits of data it can manipulate concurrently.  In the case of MS-DOS, this was 2^16, or about 640KB.  Developers, of course, used various tricks to overcome this limit, with varying degrees of success.  When 32-bit operating systems came along, the limit became 2^32, or about 4GB, roughly 4 x 10^9 bits.  This is for many current situations, but with the rise in popularity of virtualisation, as well as the ever-increasing demands of new applications, it is gradually becoming as restrictive as the old 640KB limit was in its day.

Fortunately, 64-bit computing has come to the rescue.  A full-64-bit operating system, running on 64-bit hardware, can address about 16 Exabits or 16 x 10^18 bits of memory.  At present, it seems inconceivable that any computer could possibly use such a vast amount of memory, or even that it could be manufactured in a realistic timescale.  However, it is pertinent to remember Bill Gates' famous assertion during the 1980's that "640K should be enough for anyone".

Encryption - Coming Soon To A PC Near You....

Sunday 7th February 2010

"Secrecy" is almost the same as "Confidentiality", but it is a great deal easier to say!

Ciphers, more commonly known as "Secret Codes", have been around for a very long time.  Even Julius Caesar used them.  In his day, most people could not read and write, so simple ciphers wer perfectly adequate.  As the standard of literacy has improved over the centuries, so has the standard of ciphers.  One of the most famous is that used by the Nazis for their Enigma machines.  In its day, this cipher was so advanced that it required the considerable expertise of Alan Turing and his team at Bletchley Park to break it.

Although it used to be said that "Any code that man can make, man can break", this is no longer true.  Modern AES encryption techniques, which are based on calculations involving massive prime numbers, are able to generate ciphers so secure as to be unbreakable within any realistic timescale.  Although they are difficult to break, these ciphers are easy to make.  Indeed, they are well within the capabilities of any modern PC, being used with those "secure" websites which have the prefix "https://" in the browser's address bar and the little padlock symbol in the bottom right corner of the screen.

Since unauthorised access to information on a PC is potentially such a serious matter when a Ministry of Defence laptop is left in a taxi or on a train, park bench, etc., it will not be long before all operating systems will automatically encrypt everything on the hard disk.

There is still one form of cipher which will always be unbreakable.  This is the technique of "Word Substitution".  On 6 June 1944, the Allies landed on "Omaha Beach" - the codename for an area of the French coast near Sainte-Honorine-des-Pertes.  Nearby was another landing area, "Utah Beach".  The important point is that neither codename gives any clue to its real location.  Omaha is actually the largest city in the state of Nebraska, in the US Midwest.  Like Nebraska, the US state of Utah is entirely landlocked.  Indeed, Utah is over 500 miles from the Pacific Ocean, while Nebraska is over 1500 miles away!

How To Win On EBay - For Less!

Sunday 31st January 2010

There really is no need to pay "over the odds", especially on an online auction site like eBay

Almost everyone has heard of eBay, even if they have never used or even visited it.  The sheer variety and range of articles offered for sale is almost unimaginable, so it is indeed fortunate that its internal search facilities are so easy-to-use.

One technique for success relies on the fact that many people did not bother paying proper attention to their English teachers at school, especially where spelling was concerned.  As a result, listings may well contain mis-spellings - for example, "e" before "i" rather than the other way round, or a single "s" where there should have been "ss".  Searching only for the correct spelling will often not turn up such items, thus reducing the number of bids they attract and therefore the price paid by the successful bidder.  Searching for a deliberate mis-spelling can often be worthwhile.  If a particular string of characters, such as a model number or specification is required, using only part of the string together with the "*" wildcard can be very useful for locating items where the seller has mistyped the information.  This is usually easier than the "brute force" approach of manually browsing whole categories.

Having found an interesting item, the next step is to bid for it.  In the same way as the experienced bidder at a live auction will not bid until he thinks everyone else has finished and the auctioneer is about to bring down his gavel, there is a well-established practice of "sniping" on eBay.  The principle is simple - place your bid as late as possible, preferably only a few seconds before the closing time.  The other biders will then have no time to outbid you.  There are a number of web-based services which offer this service, although most of them require a regular subscription.  One of the free ones, however, is also one of the best - Hammersnipe.  Being web-based, there is no need to leave a PC switched on.  Just set a bid and leave Hammersnipe to get on with it.  Easy!  It provides three free snipes each week, with unlimited snipes available by subscription.  For details, visit http://www.auctionstealer.com, then sit back and start winning!