Eunoia

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Stu Savory School report for Stu Savory
Eunoia, who is a grumpy, overeducated, facetious, multilingual ex-pat Scot, blatantly opinionated, old (1944-vintage), amateur cryptologist, computer consultant, atheist, flying instructor, bulldog-lover, Beetle-driver, textbook-writer, long-distance biker, geocacher and blogger living in the foothills south of the northern German plains. Not too shy to reveal his true name or even whereabouts, he blogs his opinions, and humour and rants irregularly. Stubbornly he clings to his beliefs, e.g. that Faith does not give answers, it only prevents you doing any goddamn questioning. You are as atheist as he is. When you understand why you don't believe in all the other gods, you will know why he does not believe in yours.

Oh, and after the death of his old dog, Kosmo, he also has a new bulldog puppy, Clara, since September 2018 :-)


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Thursday, February 13, 2020

My 60's Coding history

Last sunday, CopCar started a meme, asking What was your first coding language?.

So that was a memory test (for me), as I started coding over 55 years ago. Let's see what I can reconstruct, trying to put my coding languages into a semblance of the chronological order I used them in the sixties.

My first encounter with a computer was using a huge military R&D analog computer to program the differential equations involved in guidance systems for ship-to-ship guided missiles, ship-to-air interceptor missiles and torpedoes. So the programs consisted of wiring lists between amplifiers and feedback factors for each amplifier.

But my first experience with coding for digital computers was a (cross)- assembler. We typed code into a teletypewriter, storing it onto paper-tape. This was later read into a big (for those days) computer which assembled the code, emitting another paper tape of object code which would (when correct) be uploaded - again via a teletypewriter - into the target hardware aka a tiny missile guidance electronics. You learned to write tight, fast, code to fit into a minimal amount of memory.

The first stand-alone computer that I got to use all by myself was the Ferranti Pegasus, one of which still survives to this day in the Science Museum in London, UK. The next one, used in batch mode, was a Ferranti Mercury. It was a huge machine (weighed over a ton) with about 2000 tubes (=valves) and even a floating point unit. So I learned to program it in Autocode, a UK forerunner of BASIC I suppose. My first experience with a (batch) compiler and interpreter.

Next up, I wrote my own interpreter which took the wiring lists etc from the aforementioned analog computer and stepped through a Runge-Kutta integration loop to simulate the analog machine. Turned out to be slower! I also ran up against stability problems (differential equations for missile guidance are usually stiff enough for a Runge-Kutta method to be stable) which decades later I recognised to be fractal issues, but Mandelbrot had not written about fractals at that time.

The first real compiler and high-level language I learned was GPSS, a batch oriented simulation language. Next up were Algol 60 which I preferred for its elegance to FORTRAN which followed. All these were in batch mode on the Ferranti Atlas, at the time the fastest supercomputer in the world. They claimed that when it went offline, the computing capacity of the UK was halved;-) Then came the mind-blowing APL.

Next up was COBOL because a team of us wrote an 18-pass COBOL compiler for the AEG TR86. I also used JOVIAL for a MIL project, this was WAY before ADA became a requirement for MIL projects (around 1980). And so, the 1960s came to a close before I got a chance to learn all the exciting languages which followed :-)

I hope this answers CopCar's question :-)

Comments (4)
Cop Car wrote " So many things I never used and never accomplished. Very, very good, Stu. Thank you. Ah, yes, Runge-Kutta methods. I doubt that I've explicitly used them since completing my thesis (Investigation Concerning Non-Uniform Beam Vibrations). As I recall, I did indeed run into numerical instability - even when using double precision mode. Boeing had been kind enough to let me use their IBM mainframe (1974 - I no longer recall the machine designation). As you mentioned, our (USA) military was in love with ADA for a number of years. Interesting posting." Thankyou.
Ivan (RU) grinned "So much obscure stuff : APL, GPSS, Jovial etc. And such obscure HW!" Ferranti was big in the sixties in the UK, later it was ICL that was big in the UK.
Schorsch (D) asks "What about BASIC and C?" I didn't encounter them until the nineteenseventies.
Brian (UK) asks "So you probably knew some of the pioneers?" Well, 'knew' is too strong a verb. Remember, I was very much a junior nerd then. But I did get to meet some of them : Bauer (ALGOL), Hopper (COBOL), Schwartz (JOVIAL), Strachey (GPM) spring to mind :-)


Tuesday, February 11, 2020

Stormy Monday Blues

Starting on sunday in the north of Germany and going south on the monday, we just had the first hurricane of the year here. The whole country was on red alert. Winds over 120 mph in places; in our valley we had just 75 mph though, with slightly less damage than the Kyrill storm in 2007.

The winds came from the northwest, pushing water from the North Sea into coastal areas. People who parked on the seafront promenade road - despite widely televised warnings - almost lost their cars! Some even went windsurfing!

On the autobahn some lightly loaded but high sided trucks got blown over, thus blocking the road for everybody else, so several autobahns had to be closed :-( The national rail system closed down completely on sunday evening and most flights were cancelled too. Only now are things getting back to normal.

The storm was named Sabine here (Ciara everywhere else), because in Germany you can pay €200 to have a low (or high) pressure zone named after yourself/your girlfriend etc. What the government won't do to collect a bit of extra money! FWIW, wind turbines in Sabine generated a record 47.3 GWatt!

In Berlin the scaffolding was blown off a building site and locally trees crashed into parked (and also moving) cars. A local cyclist was also hit by a tree. Personally we stayed in the house - to comfort our dog - while the wind howled even louder outside. No tiles lost this time, but several branches from our trees.

My good friend Frank has a carpentry and roofing business, so has been very busy, even with a waiting list of people who lost roof tiles. Helping has priority!

Now, for those of you who came for the music, here's Stormy Monday Blues, recorded during Alexis Korner's 50th birthday party/all-star-blues-jam in 1978 :-)

Comments (1)
Schorsch (D) warns "Another hurricane brewing south of Iceland, 952 hectopascals and 220 km/h winds. Expect it here by sunday :-(" Let's hope it weakens off before it gets here!


Sunday, February 9, 2020

Moscow's magnificent Metro

Most big cities around the world have an infrastructure for getting commuters in and out of and around in their city. This is often an undergound railway, variously known as the subway, metro, U-bahn, or tube. These have varying quality standards from country to country, from squalid and filthy through dangerous to magnificent. I have personal experience of several of them, so here's my little summary.

New Yorkers are by a short margin the filthiest, with no respect for the otherwise quite good subway their city provides for them.

New Yorkers just throw their garbage onto the subway tracks. Starbuck's beakers, McJunk burger wrappings, drug needles, cigarette stubs and empty packs. All inflammable, so absolute disregard for the danger of a fire.

Apropos fire danger, some years ago (1987) there was a huge fire on the London (UK) tube system. Wooden escalators, gunged grease had collected under them, one spark and the inferno was there. 31 dead and 100 injured. No wonder, the London Tube system dates back to 1863.

The London Tube system is regarded as the dirtiest place in the city (and that's saying something!), inadequately ventilated, with hot fetid air being forced into your lungs with filth over 10 times the WHO recommended limit.

Escalators in general are dangerous. In Istanbul (Turkey) recently (in 2018), an escalator on their subway opened up a hole during the rush hour and swallowed a man beneath it for over an hour until he was rescued :-(

In Tokio they have stocky, burly, men - albeit in white gloves - to jam you aboard the metro cars during the rush hour :-(

At the other (upper) end of the attractiveness spectrum - to be recommended to Americans and Brits alike - is the Metro system in Moscow (Russia). It is the busiest metro system in Europe (trains every 90 seconds), and is considered a tourist attraction in itself. Beautiful stations, like being in palaces.


About 35,000 employees; train drivers' health is checked before every shift, clean platforms and tunnels. Punctual. Their own safety record is very good except for Islamic terrorist bombings every couple of years or so :-(

A single ticket to get you from A to B is valid for 1½ hours irrespective of distance travelled and costs about 70 cents. Cheap! I used an all-day tourist ticket and visited a lot of the beautiful stations shown by Google. Google has a great collection of photos of magnificent Moscow Metro stations.

If you are ever in Moscow, be sure to see the Metro system, well worth it :-)


Friday, February 7, 2020

Telescope resolution revisited

Last month I ranted about stupidly bad astronomy Inter alia, I wrote that "Back in 1969 we didn't have telescopes powerful enough to even see the moon landing from Earth. And the Moon is only 1¼ light-seconds away from the Earth. We didn't have them by 1991 and we don't even have them today!"

Several of you have since asked "Why not?" and "What can our best telescopes see?" and "What about space-based telescopes like Hubble?"

The resolution of a telescope is proportional to the size of the main mirror. The Hubble telescope's mirror is only 2.4 meters across (because it had to fit into the Space Shuttle's bay to get into orbit). Hubble is in a close Earth orbit and so 1¼ light seconds away from the Moon. This means that a single pixel of visible light as seen by Hubble's camera is 90 metres across on the Moon. But the 1969 Eagle lander is only 5 meters across, so Hubble can't resolve it.

The biggest Earth-based telescope is the GTC on the Canary Islands. It has a 10.4 meter mirror. So the smallest object it can resolve on the Moon would be 20 meters across. Still not enough. It would need a mirror 80 meters across to see Eagle as two pixels; that's Why not :-)

So, if we want to see Eagle, the other option is to get closer than 1¼ light seconds. NASA did this by putting the LRO (Lunar Reconnaissance Orbiter) into close orbit around the Moon (12 to 100 miles altitude). Sure, the LRO camera is smaller but really close in. So it can resolve items only 18 inches across into one pixel. So here's the LRO photo of Tranquillity Base :-)

The white blob is the Tranquillity Base lander. You can even see the tracks where the astronauts Armstrong and Aldwin walked over to the crater called West and down to set up the scientific instruments, so YES, you doubters, Nasa was there in 1969 :-)

Next conspiracy theory? Perhaps NASA is not humans, but aliens (guys from Area 51 ?) trying to get back home using our very primitive technology? ;-)


Monday, February 3, 2020

Domino puzzle

Can you rearrage the dominoes shown below so that both vertical columns and both horizontal rows all add up to the same number?

Hint : it's an Illuminati puzzle, so the four sums are each twentythree.

Update 7/2/2020 : Oh come on, no takers? It's not THAT hard.

Comments(1)
Jan (D) wrote " The hint made it easy. The total of the rows and columns would be 4 x 23 = 92 while the pips on the pieces add up to 69, leaving a difference of, too, 23 which must be the sum of the four corners. So the corners must be 6, 6, 6 and 5, making the (4,4) the only piece that can not be in a corner. This narrows it down enough to find a solution:"

Correct. Well done Jan! :-)


Link to the previous month's blog.
Recent Writings
My 60's Coding history
Stormy Monday Blues
Moscow's Metro
Telescope resolution
Domino puzzle
Brexit tonight :-)
Scud Running kills
Pizza my arse!
Astronomically Stupid
Megxit
U.S. Aircraft Carriers
No memory lockout :-(
Factorial fun
Going to Mars
Holiday avian dining
Valid_Dated
Good Omens & Puckoon
Khoroshevskoye Shosse
Winter solstice
Torn ligament :-(
Paraskevidekatriaphobia
Custom Bike Show
PISA results worsen
Hundertwasser brewery
Free Lunch :-)
In Germany's oldest Inn

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Blog Dewey Decimal Classification : 153
FWIW, 153 is a triangular number, meaning that you can arrange 153 items into an equilateral triangle (with 17 items on a side). It is also one of the six known truncated triangular numbers, because 1 and 15 are triangular numbers as well. It is a hexagonal number, meaning that you can distribute 153 points evenly at the corners and along the sides of a hexagon. It is the smallest 3-narcissistic number. This means it?s the sum of the cubes of its digits. It is the sum of the first five positive factorials. Yup, this is a 153-type blog. QED ;-)
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