OK you might ask why I have just offered you a sweet and asked if you want to see my little cat. I hope your parents warned you about accepting lifts, sweets and invites to see cute animals from weirdos, strangers and random passersby.
I have noticed that a lot of people accept things from the internet in the same way as an over trusting person might accept a sweet, lift or a trip to see a cute animal from some random stranger. Out on the internet there seem to be a lot of people who are offering free goodies, they are offering information (just like I do), free games, software gadgets and advice on all manner of subjects. Some of this advice is very good advice such as the advice given by the RSGB for any person who wants to get involved in radio electronics as a hobby. But some of the advice is rather bad, I have seen some bits of advice which are very badly written. For example I have seen recipes for chemicals which are dangerous. Some of these cookbooks use methods which are dangerous or fail to include reasonable warnings about some of the menaces posed by the materials or methods used. Such bad chemistry is sad, but the saddest thing I have ever seen on the internet is a hate site which claims to be a truthful site devoted to history.
Another bad thing I have seen are the array of sites offering something for nothing, these are the sites which offer free goodies such as software and gadgets. The problem is that unless you know the person who wrote it or can trace it back to a good trustworthy company such as Microsoft then be very careful. While I do not like everything that Microsoft do, I view them as more trustworthy than some random person with a website. The reason is that Microsoft need to keep a company going, and if Microsoft release a product which is going to steal money or data from the user then Microsoft fear the reaction of the courts and the general public.
So the next time you see some software which offers to make it more easy to play WoW or do something else for you, then think long and hard. How do you know it does not contain something nasty such as code intended to steal you WoW gold or worse still your credit card number ?
Also some honest person who writes free software might with honest intentions write something, it might work on their machine but there is a danger that it might not work on your machine in the same way, or worse still when something else is updated then it might contribute to some nasty failure. I am a great fan of the swiss cheese model of accidents. If you look at the Chernobyl, many air / road crashes then you will see how some defects can appear in a system and stay there dormant for a long time. When a special combination of defects exists then the accident will occur.
At Chernobyl a vast list of problems existed.
1. The basic reactor design caused it to have a positive void effect
2. The control rods had a design fault
3. The operators were not under good supervision, they were allowed to try out experiments or break the rules of the plant
4. The operators were badly trained, they were unaware of some of the failings of the reactor design
5. Due to downward adjustments in the reactivity of the core the core was partly poisoned with xenon
6. The operators were able to withdraw more control rods than the operational rules for the plant allowed
7. The operators were zonked out from too little sleep
8. No one person in the control room was in charge of the whole plant, such a person if they had existed might have spotted the fact that things were getting out of control and stopped the experiment at a more early stage.
9. The experiment was badly designed, it was intended as a test of the hypothesis that the kinetic energy in the turbine could provide electrical power to run vital systems (water pumps) if the reactor SCRAMed and lost its diesel sets and the electricity connection from the outside world. Why then did the planner of the experiment start by adding to the switch yard connections to a load of the same size as the safety critical systems of the power station, get the station pumps running on diesel power (or import electric power from the grid) and then SCRAM the reactor (which would be running at 3000 MWt) at the same time as opening the high voltage switch to the outside world ? This might not be a perfectly designed experiment but I suspect that the method of getting the same data which I worked out over five minutes would have had a series of safety advantages over the method used in April 1986.
OK we have enough of my thoughts about Chernobyl, but what may happen from your free gizmo which you down load from Mr Random and install on your PC is that you might introduce a latent defect into your computer, this latent defect is like a precancerous cell. It can lurk in your computer for years before evolving into something very nasty when it aligns with several other latent defects to create an active monster of a problem.
Also on the web I have to warn you about “nothing for something”, there are lots of nasty money making schemes which are designed to get money or other things from you. In return you will get nothing.
Do not have nightmares or get into a total panic, just please be careful. I would suggest that all of you reading should visit one web site which is all about how to use the web in a good, safe and legal way. There is a tutorial there that I hope will wither teach or remind you about an important series of things.
NB The main reasons why I think that my alternative experiment plan for the ill-fated nuclear safety experiment is better is that at a higher power the positive void effect is cancelled out by other effects which relate to the temperature of the fuel and moderator. Also the reactor running at a steady 3000 MWt will have some control rods already inside, by pushing these and other rods into the core the graphite tip effect would not hve caused a spike in the reactivity (heat output). Also the core would have been well fed with cold water which would lower the chance of the coolant flashing to steam. If the turbine + alternator had been unable to make electricity for the pumps then a load (such as laundry irons [http://www.neimagazine.com/graphic.asp?sc=2037503&seq=5] or the streetlights of the town) would either go off or suffer damage if the voltage spiked if the regulation failed which is a less dangerous outcome than wrecking the electrical systems in a nuclear plant.