The author

Moore's Switch: Programming, We're Doing it Wrong!

Steven Pemberton, CWI, Amsterdam



About me

Researcher at CWI in Amsterdam (first non-military internet site in Europe - 1988, whole of Europe connected to USA with 64kb link!)

Co-designed the programming language ABC, that was later used as the basis for Python.

Wrote part of GCC.

One if the first handful of people on the open Internet in Europe.

At the end of the 80's built a system that you would now call a browser.

Organised 2 workshops at the first Web conference in 1994.

Chaired HTML WG for the best part of a decade.

Co-author of HTML4, CSS, XHTML, XForms, RDFa, etc.

1957: The first municipal computer (Norwich, UK)

The First Computer in Norwich

Just one of 21 cabinets making up the computer.

2015: The Raspberry Pi Zero

Raspberry Pi in Norwich

Which is faster?

Want to guess which of the two computers is the faster, and by how much?

Which is faster?

The Raspberry Pi is about one million times faster...

If they had run the Elliot 24 hours a day for 10 years, it would have done the amount of computing you can do on a Raspberry Pi Zero in about 5 minutes!


Elliott 405 Raspberry Pi Zero Factor
Year 1957 2015 58
Price £85,000 (1957)
(£2M-7M in 2015 money)
£4 ½M-2M
Instruction cycle time 10.71-0.918 ms (93-1089 Hz) 1 ns (1 GHz clock) 1M
Main memory 1280 bytes 512 MB ½M
Secondary memory 16 kB drum store 8 GB (typical SD flash card - not included) ½M
Tertiary memory 1.2MB (300 kword magnetic film) 1TB (Typical - not included) 1M
Output bandwidth 25 characters/s 373 MB/s (HDMI) 60MB/s (USB) 2M-10M
Weight 3-6 tons 9 g ½M
Size 21 cabinets, each 2m x 77cm x 77cm 65 x 30 x 5.4mm 2.3M
Median UK wage Around £250 (men), £125 (women) Around £30000 (men), £25000 (women) 120-200

(Updated version of this original)


So the Raspberry Pi is:

A factor of a million million (billioen in Dutch, trillion in English).

A terabyte is a million million bytes: nowadays we talk in terms of very large numbers.

Want to guess how long a million million seconds is?

A million million seconds

Is 30,000 years...

In other words, a really big number...

Moore's Law

Funnily enough, a million million is almost exactly what Moore's Law would have us expect for that length of time (even though 1957 is before Moore's Law was thought of, and predates integrated circuits).

Happy Birthday Moore's Law!

Moore's original graph

In 2015 Moore's Law turned 50 years old.

Or less prosaically: Moore's Law was 33⅓ iterations of itself old.

The reports of Moore's Law's death have been greatly exaggerated

The first time I head that Moore's Law was nearly at an end was in 1977. From no less than Grace Hopper, at Manchester University.

Since then I have heard many times that it was close to its end, or even has already ended. There was a burst of such claims in 2015, which caused a wag to tweet

"The number of press articles speculating the end of Moore's Law doubles every eighteen months."

A data point: The Raspberry Pi

Two Raspberry Pi's, both alike in dignityAs an excellent example, in February 2015, almost exactly three years after the announcement of the first version, version 2 of the Raspberry Pi computer was announced.

Raspberry Pi

Since three years is exactly two cycles of Moore's Law, does the new Raspberry Pi deliver a four-fold improvement?

Moore's Law

Computer speeds 1988-2016So Moore's Law has been doing its work, and computers have been getting exponentially faster.

In 1988 my laptop had a power of 800. My present one has a power of nearly 30M. That is 15 doublings!

Exponential change

This is November 2006:

November 2006

Six years later, the cheapest 4GB stick cost €2.99.

What exponential growth really means to you and me

Often people don't understand the true effects of exponential growth.

A BBC reporter: "Your current PC is more powerful than the computer they had on board the first flight to the moon". True, but oh so wrong.

Take a piece of paper, divide it in two, and write this year's date in one half:



Now divide the other half in two vertically, and write the date 18 months ago in one half:



Now divide the remaining space in half, and write the date 18 months earlier (or in other words 3 years ago) in one half:



Repeat until your pen is thicker than the space you have to divide in two:



This demonstrates that your current computer is more powerful than all other computers you have ever had put together (and way more powerful than the computer they had on board the first moonshot).

In other words

Since the 50's, computers have become incredibly cheap and powerful, and yet we are still programming them with programming languages that were designed to save the computer work.

In fact most computers spend most of their time idle. Here is my computer as I write these slides. The bump at the end is caused by taking the screen shot.

A computer idling

What we need to do is take the load off the programmer, and put more of it on the computer. Use some of that spare power!

Let's go back to 1957

In the 50's, computers cost in the millions. Nearly no one bought them, nearly everyone leased them.

To rent time on a computer then would cost you of the order of $1000 per hour: several times the annual salary of a programmer!

When you leased a computer in those days, you would get programmers for free to go with it.

Compared to the cost of a computer, a programmer was almost free.

The design of programming languages

TypingIn the 50's the computer's time was expensive.

So a programmer would write the program, copy it to special paper, give it to a typist, who would type it out, then give the result to another typist who would then type it out again to verify that it had been typed correctly the first time.

Why all this extra work? Because it was much cheaper to let 3 people do this work, than to let the computer discover the errors for you.

The design of programming languages

And so programming languages were designed around the needs of the computer, not the programmer. It was much cheaper to let the programmer spend lots of time producing a program than to let the computer do some of the work for you.

Programming languages were designed so that you tell the computer exactly what to do, in its terms, not what you want to achieve in yours.

Back to 2016

It happened slowly, almost unnoticed, but nowadays we have the exact opposite position:

Compared to the cost of a programmer, a computer is almost free.

I call this Moore's Switch.

Moore's Switch

Moore's Switch illustrated
Relative costs of computers and programmers, 1957-2016

But, we are still programming in programming languages that are direct descendants of the languages designed in the 1950's!

We are still telling the computers what to do.


1960: Algol60

procedure bottles(n); value n; integer n;
    if n < 1 
    then outstring(1, "no more ")
    else outinteger(1, n);
    if n = 1
    then outstring(1, "bottle")
    else outstring(1, "bottles");
    outstring(1, " of beer");

integer i;

for i := 99 step -1 until 1 do begin
   bottles(i); outstring(1, " on the wall, ");
   bottles(i); outstring(1, "\n");
   outstring(1, "take one down and pass it around, ");
   bottles(i - 1); outstring(1, " on the wall.\n");

Now: Python

for quant in range(99, 0, -1):
   if quant > 1:
      print quant, "bottles of beer on the wall,", quant, "bottles of beer."
      if quant > 2:
         suffix = str(quant - 1) + " bottles of beer on the wall."
         suffix = "1 bottle of beer on the wall."
   elif quant == 1:
      print "1 bottle of beer on the wall, 1 bottle of beer."
      suffix = "no more beer on the wall!"
   print "Take one down, pass it around,", suffix
   print "--"

Declarative programming

A new way of programming: declarative programming.

This describes what you want to achieve, but not how to achieve it.

Let me give some examples.

The first declarative definition

Declarative approaches describe the solution space.

A classic example is when you learn in school that

The square root of a number n is the number r such that r × r = n

This doesn't tell you how to calculate the square root; but no problem, because we have machines to do that for us.

Procedural code

function f a: {
    x ← a
    x' ← (a + 1) ÷ 2
    epsilon ← 1.19209290e-07
    while abs(x − x') > epsilon × x: {
        x ← x'
        x' ← ((a ÷ x') + x') ÷ 2
    return x'

What does 'Declarative programming' mean?

A Procedural Clock

A clock in C, 1000+ lines

1000 lines, almost all of it administrative. Only 2 or 3 lines have anything to do with telling the time.

And this was the smallest example I could find. The largest was more than 4000 lines.

A Declarative Clock

type clock = (h, m, s)
displayed as 
   circled(combined(hhand; mhand; shand; decor))
   shand = line(slength) rotated (s × 6)
   mhand = line(mlength) rotated (m × 6)
   hhand = line(hlength) rotated (h × 30 + m ÷ 2)
   decor = ...
   slength = ...
clock c
c.s = system:seconds mod 60
c.m = (system:seconds div 60) mod 60
c.h = (system:seconds div 3600) mod 24

A Running Declarative Clock

The Views System


XForms is a declarative system that lets you define applications.

It is a W3C standard, and in worldwide use.

Example: 150 person years becomes 10!

A certain company makes BIG machines (walk in): user interface is very demanding — traditionally needed 5 years, 30 people.

With XForms this became: 1 year, 10 people.

Do the sums. Assume one person costs 100k a year. Then this has gone from a 15M cost to a 1M cost. They have saved 14 million! (And 4 years)

Example: Insurance Industry

Manager: I want you to come back to me in 2 days with estimates of how long it will take your teams to make the application.

(Two days later)

Programming man: I'll need 30 days to work out how long it will take to program it.

XForms man: I've already programmed it!

Example: NHS

The British National Health Service started a project for a health records system.

One person then created a system using XForms.

(Some) Implementations

CM Pro (Netherlands)

Inventive Designers (Belgium)

BetterForm* (Germany)

XSLTForms* (France)

Jadu (UK)

Orbeon* (USA)

XForms is also part of OpenOffice* and LibreOffice*

*=open source


For historical reasons, present programming languages are at the wrong level of abstraction: they don't describe the problem, but only one particular solution to the problem.

Once project managers realise they can save 90% on programming costs, they will switch to declarative programming.

I believe that eventually everyone will be programming declaratively: less errors, more time, more productivity.

Declarative programming allows programmers to be ten times more productive: what you now write in a week, would take a morning; what now takes a month would take a couple of days.

Advert: XForms Day at CWI planned (watch my homepage).

Slides are online.