Showing posts with label how things work. Show all posts
Showing posts with label how things work. Show all posts

Friday, 12 June 2020

How Teletext Worked

The following post was originally made in 2015 to accompany what was originally called "informative strips," now called Snacking Otaku.

To prevent readers from over-analysing this, some of the names in this 
graphic are completely made up.

How many of you remember teletext systems? I suspect many Europeans do (They didn't take off in America).

For those who have no idea what I'm talking about, a teletext system was a means of transmitting computer-generated pages of information to a wide population though TVs with special decoders via the analogue TV picture signals. It was an analogue internet (without the hyper-links, gifs, jpegs, and video streams).
They were first developed in the early-1970s and became widely-available across the globe by the 1980s, particularly in Europe. These systems were known under many names, such as Ceefax and ORACLE in the UK, Antiope in France, Televideo in Italy, Austext in Australia, and (after the demise of ORACLE) .... Teletext.
As they were carried by the picture signals, different TV channels can carry different teletext services from one another, which was truly the case in the UK. The BBC carried Ceefax while the independent channels of ITV, Channel 4 and (later) 5 carried ORACLE (which later became Teletext).
These systems were used a lot (as much people use the web services today). My dad regularly used it during the 1990s and early-2000s to check sports results. I did my self as a teen to check cinema listings. Many people did at the same time for various reasons, from checking the weather forecast to noting down recipes.
These systems only really came to an end in the last decade or so, with the transition to digital TV broadcasting. Ceefax ended in October 2012 (at the same time the last analogue TV transmitter in the UK was shut down).

The reason for this post was not to be nostalgic about teletext (mostly). The reason for this post is to celebrate a personal piece of investigatory achievement - I had finally found/worked out how teletext worked.

I bet many of you who have used such services in the past wondered how they actually worked. How did these pages of information got into your TV and where did they come from (and why you had to wait about ten seconds for your desired page to appear on screen). But when it came to finding out how it worked, most of you found only sources like this one....

(taken form my collection of old reference books)

From Reader's Digest How Is It Done? (1992 edition, p219)

It doesn't tell you much, does it. And with this level of information in regular reference books, you'll imagine that you had to study electrical engineering journals to find out more detail. Fortunately, the internet has made this of an issue, and thanks to this it was in 2013 that I finally found out how teletext worked... and discovered how neat an idea teletext was. How they actually worked is very clever. But its hard to understand using text alone. It'll help if we had pictures. That is why the subject of my next "informative strip" is teletext.


Snacking Otaku - Teletext

The following snack was originally made to accompany this post penned in 2015 that was only published now.


References and Further info

A lot of info came form this website, that I recommended seeing.

YouTube Channel Technology Connections has made a video about a related technology - Closed Captioning (and said in it about a future video about Teletext).

There are a number of software online that allows you to create your own teletext pages. A list of some are here.

The one I used is edit.tf (I suggest seeing the tutorial video on the link above before you use it. Making teletext art is very fiddly. The final result (I admit) isn't that good, so I might change it in the future.

Sunday, 21 August 2016

My New Project - What Makes Computers Tick

During the lock-out I began work on a project I had in my mind for a few years - a book about how computers work aimed at everyone.

I started sketches for this illustrated book back in May and by now (August) I have done a lot of sketches and research in the intricate inner workings of computers. I have even designed a cover for it...

Prototype cover of What Makes Computers Tick

The idea of this cover came from a memory of seeing a book cover like this back in High School. It was an old book, I admit, but I wanted to make my book feel that it could have been made some time ago. I wanted to give it a sort of timelessness. (An near-impossible fete, considering the nature of the computer industry.) A timelessness achieved through nostalgia. 

So why am I doing this?

My answer can found in the introduction I have already written for it.

Introduction 
The Miracles and Our Alarming Ignorance About Them

At the time of this book’s publication (the first half of the 21st century) we happen to live in a world full of incredible technology. If someone from centuries ago would somehow see our time (and see all our wonderful abilities in action) that person would think we all become sorcerers. We have been able to build artificial organisms and sent them to other planets. We also made them take us across the Earth and make things for us. We have become able to capture light and sound and send it across vast distances, to allow others to experience the same things we have. We have the means to gather and bring up any piece of our vast collective knowledge wherever we are and at any time, and no matter how obscure it is, it can be found before you can say “googolplex.” And with these means we have been able to map more planets outside our solar system and other things, including our genes. Also, we have been able to make more accurate predictions with things like the weather and the state of the marketplace (with increasing success over time). And, if we find the real world boring, we can create new exciting worlds to play in … or test ideas out before implementing them for real. And thanks to such “simulations” we have been able to build things that would have been considered impossible just decades earlier.

Worded like this, it sounds like we’re living in a world full of magic. But this is our world in the 21st century. None of this is an exaggeration. Between the time of that ancestor and now we have developed a lot of new tools and technology that has made this world possible. Technology you would have trouble describing to that ancestor (If you happen to end up in the ancestor’s time with no examples to demonstrate. It could happen someday.). You could probably list ten of them right now in an instant.

Trains, cars, aeroplanes, telephones, cameras, microwaves, record players, plastic, TV, fridges, you can go on….

But, I bet when it comes to one particular one, many of you may not think of it instantly. You may have thought of it after thinking of others first. It’s not a surprise that is case, because most of the time we don’t think about them… mostly because many of them are invisible in daily life (except the very obvious ones you probably use at work or leisure). I know that some of you will have thought of this thing first, as you may be very aware of how many they are and what they do. As you are reading this many of these things are tracking stock in stores, transferring money from bank account to bank account, sending bills and statements to customers, spotting suspects in CCTV, making things to a design with very high precision, predicting the weather tomorrow, generating alternate worlds for pleasure, mapping the genes of individuals to detect “defects,” and giving life to and guiding those artificial organisms I talked about earlier (you know them better as “robots”).

It can be easily argued that of all the “miracles” we have developed since the days people were burnt to the stake as “witches,” this particular one has made the biggest impact. Without it, we will be back to life before World War II. A time when thousands of people were employed just to crunch numbers for various reasons, from managing a company’s finances to calculating the stress forces on Zeppelins.

These people were once given a name. A name that was later adopted to name the “miracles” that replaced them. A name that became so linked to these machines that soon people forgot it was once used to describe people – computers.

From large machines used in academia and data centres containing “the cloud” to devices on your desk or in your pocket (or inside you), computers are everywhere and come in many forms. They have even embedded themselves in other things, such as cars and kitchen appliances. So even if you try to go “offline” you will interact with at least one computer without knowing it.

But here’s a thought…. How many of us know how they work? I don’t mean stuff like you need to press control+alt+delete to get the menu that allows to get Task Manager or to change your password on your Windows PC. I mean their nuts and bolts. What makes them tick. I’m sure a lot of you have at least once thought about this question. With them everywhere and you using them almost every day it would be odd not to have thought of asking “how computers work?” But how many of us managed to find a satisfactory answer to that question?

This is what has been bugging me (and made me make this book) – attempts to explain how computers work to people (children and adults) with almost no scientific or technical knowledge to begin with have been …. terrible. In many attempts to explain how computers work the writers have been too simplistic or wrote too long a passage and filled it with jargon, causing confusion and alienation. A lot just point out the parts of a computer and say this does this and that does that. This is what I experienced for years. It wasn’t until I was in higher education (studying multimedia in college and computer animation in university) that I finally worked out how computers really work. Thanks to some hands-on experience making interactive media and learning how computers model virtual worlds, I gained my mental picture of how all the components of a computer interact with each other. And in doing so learned why I didn’t get “it” until then. I have been an avid reader on the subject of how things work and got high grades for physics. Surely I could have worked it out before then, but I didn’t. All the text I have read didn’t do a good job explaining it. Why?

They are two basic problems that come to finding out how computers work for yourself (and writing about it). First off, if you get hold of a computer and open it up to take a look inside you are confronted with a selection of wires, chips and circuit boards. Unlike a mechanical clock, they are no gears or wheels to see moving. No single tangible indicator to help build up a picture of how it ticks. Second of, computers are no all-in-one boxes. They are made of several component systems that work together. It’s like a car. Cars are made up of several systems that work together – transmission, brake, steering, suspension, electrics and so on. It would be ridiculous (in trying to explain how cars work) to sum them all up in a single paragraph. But many have done just that when trying to work out or explain how computers work. With no obvious moving parts (except disk drives and cooling fans – or robot limbs) and a multisystem construction, it’s no wonder many have failed the task of explaining how computers work to non-nerds. It’s no wonder (like cars) computers entered the domain of nerds.*

*I don’t see a difference between guys who talk about the differences between Fords and Chevys for hours and guys who talk about the differences between Android and Apple devices for the same amount of time. It’s the same mentality all fans have. If you love something so passionately to bother to learn everything about them (from football to that singer everyone’s talking about now) you are (technically) a nerd of that subject.

So what? Some of you ask? I don’t need to know how it works. As long as it does what I want it to do, I’m happy. Okay, continue been ignorant. But what if your computer (or any computer) does something you didn’t want it to do? What if it crashes and you loss all your data you worked hard creating? What if your processor or internet connection begins to slow down? What if someone stole your password and messed about your accounts? What if your bank sent you something not meant for you because you shared a name and date-of-birth of someone else? What if your sat-nav directs you the wrong way up a one-way street? Surely when incidents like these happen to you or in the news you want to know how such faults are possible. This is when (I think) you need to be taught how computers work. If you have this knowledge you may be able to understand how such errors happen and be able avoid such problems yourself in the future.

As more computers come into existence and more of us actively login I think there is a need for this book more than ever before. Without an accurate easy-to-understand description to work with, many people have gained a lot of wrong ideas about computers and what they are able to do. This happens to all new technology. When a new gizmo appears, the average Joe has no idea what makes it tick. And when some people get some experience with them they spread rumours and misconceptions about them due to their lack of understanding of the science behind them or false correlations between it and something unrelated (usually something medical). This is how we get ideas like, cameras taking people’s souls, people on TV been able to see you as you watch them, putting metal cutlery in a microwave will make it explode, or that high use of cellphones cause brain tumors.

Computers are no different. You may have heard (and believe) some misconceptions about them, such as the idea that they are some form of artificial brain that becoming increasingly intelligent. An increasing intelligence that might one day surpass the collective intelligence of all humans … and when that moment comes they’ll think that they don’t need us anymore and kill us off by activating the world’s nuclear missiles by playing tune down a phone line. That last bit is based on a lie a law enforcement officer may have said to convince American federal judge Marianna Pfaelzer to convict high-profile computer hacker Kevin Mitnick in 1999 …. which she believed, making her rule that after serving 46 months in jail he was banned from touching a single computer or dial-tone telephone for three years.
The fact that a judge (a presumingly highly-educated person) bought such a lie highlights how far this ignorance has become. And with computers doing a lot of things in society that is a worry. We have had false ideas that computers are “brains” and that a robot uprising is coming to cloud our judgements about everything related to computers. These are ideas that first came about when computers were new to the world and only the guys in white coats operating these early colossuses knew the truth about them – computers are stupid. They are not “brains,” they are just piles of wired up switches designed to do math very quickly. They are like trained animals following master’s commands. But that image was dull, so journalists and science-fiction writers filled our ignorance gap with metaphors and B-movie plot devices to make them sound interesting.
Although computers have changed shape and have been made of different stuff since those early “monsters,” the way they tick is exactly the same. And no matter what they do, from composing music to identifying species of moth, what they all doing is the same thing – mathematics done very quickly.

It’s no surprise if you take a look at their history and origins. When science historians write about the history of computers they also tend to link it with the history of calculators, because they have the same origins – devices designed to aid the adding up of numbers. Devices we began to need after we began to count beyond our ten fingers and toes.

To begin to understand what makes computers tick this is a good starting point – how do you make a machine add up? Curious? Want to know more? Don’t want to feel alienated by a selection of microchips in a box …. again?

Let’s us begin with their heart ….. the processor
(and find out how you make a machine add up).

[Enough Said]

Monday, 29 June 2015

How Motion Pictures Work

Back in February (as a duty of editor of the NAS Times newsletter) I took part in a group that visited various places in Glasgow.
On our first trip that month we went to the Mitchell Library. At the time of our visit, it was holding an exhibition about cinemas in the city. Glasgow had a lot of cinemas. In fact, in the 1930s Glasgow had more cinemas per head of population than any other city in the world.

It was after seeing this exhibition (which showed a few old projectors and various other pieces of cinema paraphernalia) that I thought about making another informative strip (like the one I did back in November).

I didn't chase this idea until just a few weeks ago when I was in the mist of making this animation.

The subject of this strip is motions pictures. As someone who loves animation, I'm fascinated how it is possible for drawings, models or photographs to become "alive" on screen. Its a very interesting thing to investigate. It involves biology as well as technology. Reading about how movies were invented is a very interesting story, involving many characters, especially Eadweard Muybridge, and mysteries, like the disappearance of Louis Le Prince. I might one day do something about this, but for now here's how motion pictures work....

Featuring The Masked Pidgeotto.


Took a bit longer than expected to make.

UPDATE: June 2017

Last night I wrote this paragraph. I think its does a better job than this strip...

“The Illusion of Life”
Human vision has the sense rate of about one tenth of a second. This means that if an object travelling across a human’s field of vision takes less than one tenth of a second to do so the eye won’t see it. If an invisible person moved an object in small intervals in that field of vision, if those movements happened in a rate more than ten times a second, it’ll appear to the eye that the moving object is “alive.” The same thing happens with still images. If you flash still images into someone’s field of vision at least 12 times a second (with some mechanism to block the image briefly as it changes to the next one) they will appear to move. But the more images you flash a second the smoother the movement appears to the eye, as the blank spaces between images become less noticeable. According to Thomas Edison, the ideal minimum rate for “flicker-free” movies is 46 images per second - "Anything less will strain the eye." 

It demonstrates what I am trying to do with my computer book.