Date: 2009-06-08 14:39 Subject: Burning Rubber, But Not Gas Security: Public Tags: motorcyle, race, tt, ttxgp

The Isle of Man Tourist Trophy, or “TT”, is one of the Worlds most famous and iconic motor races, where the public roads of the island are turned into a motorcycle race track.  A 38 mile (61km) course takes bikes around the island at speeds of up to 200mph (320kmh), with the fastest bikes averaging around 130mph (209kmh) over the lap.

This Friday, an important new page will open in the history of electric vehicles: the TTXGP.   The aim of the TTXGP is to build and race a zero-carbon superbike around the standard course, for two laps.  Although any zero-carbon technology is allowed, the entrants are all electric, powered by batteries; 76 miles is a long way, so clockwork or rubber-band powered is not going to be an option, and there are certain public safety issues associated with nuclear powered motorbikes, even supposing you could find a rider willing to sit on one.

Visually, the bikes look very much like petrol bikes, and in fact usually a standard road bike is the starting point for constructing the electric version.  Brakes, suspension, frame, controls are all fairly standard, but what is usually the petrol tank is now generally full of batteries.  The motors are electric, with no gearbox, and of course these vehicles are pretty much noiseless.

The electric technology looks somewhat puny in comparison with the petrol bikes, but the electric vehicles are expected to be able to reach top speeds of around 70mph.  Of course it is hoped that if this kind of racing becomes a regular fixture, then this will drive innovation in battery and motor technology.  As any engineer will tell you, you can have a hundred ideas on paper about how to build something, but the execution of building something is where the really great innovation comes from.

I’m looking forward to seeing what these bikes can do on Friday, and also hoping that this does create practical road bikes in the not-too-distant future.  An electric bike with a range of, say, 200 miles at speeds of up to 70mph seems to me like a useful vehicle for commuting.

Date: 2009-05-07 07:22 Subject: Letter to the DVD Industry Security: Public Tags: dvd, industry, movies

The DVD format is a big advance over the VHS tape, but in some ways the technology tail is being allowed to wag the entertainment dog.  Can I point out a few things to you studios and DVD producers?

1. Having different navigation on every DVD is a pain in the arse.  I know you want to make it look nice (and unique), but fundamentally I just want to select something from the menu. Mostly I just want the movie to play.  So, here are some don's for you:

- Don't redesign the cursor.  I need to know what I'm, pointing at.  Don't just use colours.  I don't know that  you think that 'red' is the cursor and 'yellow' is non-selected.
- Don't spatter the selectable icons all over the screen like a swarm of jellyfish.  Line the icons up so I know how to jump from one to the other.
- Don't play a 15 second video clip every time I come back to the menu.  I've seen it now.  The first time was enough.
- Don't add visually confusing backgrounds so that it's hard to see which is part of the menu and which not.
- Don't add extra levels of menus just because you want to make it look lke a "spaceship control panel" or some such.  Annoying.  Time-wasting.

2. Don't show me warning videos (or screens full of text) about piracy or from the FBI. I know your point of view, and I don't care.  I don't know who you think is interested in this message because:
- The real pirates have already decided to set up their duplication factories in Asia.  They will not watch you piracy video.  If we're lucky, they'll strip it off in the pirate version, and make our lives better.
- Normal home users like me are not engaged in piracy.  We don't need to be told (every time) that piracy is bad, and we don't want to watch your poxy infomercial.
- I don't believe that even if I was on the horns of the dilemma of "shall I copy and sell this DVD", that watching your trailer or reading what the FBI have to say would make any difference to me whatsoever.

Producers please note: making these parts of the disc non-skippable is not making anyone happy.  Please stop it.  Actually, this is an incitement to rip the DVD and watch it in another format: at least then we don't have to sit through unwanted rubbish.

3.  Don't show me your logos and idents.  Especially don't make these bits non-skippable.
- I don't care that you're called Warner or Sony, and I won't remember that you're asociated with this movie.
- I don't care who provided the audio technology, and I don't want to watch your promo/ident
- I don't want any of this non-skippable crap from slowing down watching the movie.

4.  Don't show me any trailers.
I realise that if I get a rental disc that it will have film trailers.  I don't want it, but I'm resigned to it.  Please note that I will skip them evey single time.  But if I buy a disc, a definitely don't want any trailers.  I bought the disc for a specific movie, and that is what I will watch repeatedly, not your ageing trailers.

Especially don't insert ads (e.g. for chocolate bars) in there too.  I do not (will not) watch commercials ona DVD disc.  If you insult me like this, then I will retaliate by not buying your confectionery.  Once again, if you fill the disc with unwanted crap, then you're playing into the hands of DVD rippers and possibly also pirates.  A format that offers the movie without all of that unwanted noise is a product that people desire.

5.  Don't show me any multi-lingual warnings after the movie has finished.  I still don't care.  Also, you know now that I speak English, because I selected that from the menu to start with.  Don't show me irrelevant rubbish when the technology allows you not to.

If you can do these simple things for me, we're going to get on fine.  Otherwise you're just making enemies and it's you that suffers in the end.  Transmission ends.

Date: 2009-04-09 12:02 Subject: Calculating Easter Day Security: Public Tags: algorithm, easter day

 With Easter approaching, I was thinking about the calculation for Easter day.  Back in the 1970s I had one of the first affordable programmable calculators, the Sinclair Cambridge Programmable, and this came with a book of algorithms for calculating all kinds of interesting things, mainly science and engineering related.   It even had a rudimentary version of the Lunar Lander game, although with only the altitude and speed shown on the display, you had to use your imagination.

One of the sample algorithms offered with the calculator was a routine to work out Easter day for any given year.  Easter Day is a moving feast, based on the movements of the moon.  Specifically you have to work out the date of the Paschal Full Moon, then Easter day falls on the following Sunday.  As usual Wikipedia has extraordinary levels of detail on the available algorithm, and as far as I remember the steps for the Sinclair calculator looked like those listed under Anonymous Gregorian algorithm:

a = Y mod 19

b = floor (Y / 100)

c = Y mod 100

d = floor (b / 4)

e = b mod 4

f = floor ((b + 8) / 25)

g = floor ((b − f + 1) / 3)

h = (19a + b − d − g + 15) mod 30

i = floor (c / 4)

k = c mod 4

L = (32 + 2e + 2i − h − k) mod 7

m = floor ((a + 11h + 22L) / 451)

month = floor ((h + L − 7m + 114) / 31)

day = ((h + L − 7m + 114) mod 31) + 1

So in other words in a series of quite simple fixed point calculations you can go from the year number to a month (March or April) and a day number.  Quite simple and elegant, and ideal for my calculator, which only had a 36 steps (operations) in its memory.