Early Computing: Crash Course Computer Science #1

0:03 Hello world, I’m Carrie Anne, and welcome to CrashCourse Computer Science!

0:06 Over the course of this series, we’re going to go from bits, bytes,

0:09 transistors and logic gates,

0:11 all the way to Operating Systems, Virtual Reality and Robots!

0:14 We’re going to cover a lot,

0:15 but just to clear things up- we ARE NOT going to teach you how to program.

0:18 Instead, we’re going to explore a range

0:20 of computing topics as a discipline and a technology.

0:23 Computers are the lifeblood of today’s world.

0:25 If they were to suddenly turn off, all at once,

0:27 the power grid would shut down, cars would crash, planes would fall,

0:30 water treatment plants would stop, stock markets would freeze,

0:33 trucks with food wouldn’t know where to deliver,

0:35 and employees wouldn’t get paid.

0:37 Even many non-computer objects- like DFTBA shirts and the chair

0:40 I’m sitting on– are made in factories run by computers.

0:44 Computing really has transformed nearly every aspect of our lives.

0:47 And this isn’t the first time we’ve

0:48 seen this sort of technology-driven global change.

0:50 Advances in manufacturing during the Industrial Revolution brought

0:53 a new scale to human civilization- in agriculture, industry and domestic life.

0:57 Mechanization meant superior harvests and more food, mass produced goods,

1:01 cheaper and faster travel and communication,

1:03 and usually a better quality of life.

1:05 And computing technology is doing the same

1:07 right now– from automated farming and medical equipment,

1:10 to global telecommunications and educational opportunities,

1:12 and new frontiers like Virtual Reality and Self Driving Cars.

1:16 We are living in a time likely to be remembered as the Electronic Age.

1:21 With billions of transistors in just your smartphones,

1:23 computers can seem pretty complicated,

1:25 but really, they’re just simple machines that perform

1:28 complex actions through many layers of abstraction.

1:31 So in this series, we’re going break down those layers,

1:34 and build up from simple 1’s and 0’s,

1:36 to logic units, CPUs, operating systems, the entire internet and beyond.

1:42 And don’t worry, in the same way someone buying t-shirts

1:44 on a webpage doesn’t need to know how that webpage was programmed,

1:47 or the web designer doesn’t need to know how all the packets are routed,

1:51 or router engineers don’t need to know about transistor logic,

1:54 this series will build on previous episodes but not be dependent on them.

1:58 By the end of this series, I hope that you can better contextualize computing’s

2:01 role both in your own life and society,

2:04 and how humanity's (arguably) greatest invention is just in its infancy,

2:08 with its biggest impacts yet to come.

2:10 But before we get into all that, we should start at computing’s origins,

2:14 because although electronic computers are relatively new,

2:19 the need for computation is not.

2:24 INTRO The earliest recognized device for computing was the abacus,

2:31 invented in Mesopotamia around 2500 BCE.

2:34 It’s essentially a hand operated calculator,

2:36 that helps add and subtract many numbers.

2:39 It also stores the current state of the computation,

2:41 much like your hard drive does today.

2:43 The abacus was created because,

2:44 the scale of society had become greater than what

2:46 a single person could keep and manipulate in their mind.

2:49 There might be thousands of people in a village or tens of thousands of cattle.

2:53 There are many variants of the abacus, but let’s look at a really basic version

2:57 with each row representing a different power of ten.

2:59 So each bead on the bottom row represents a single unit,

3:02 in the next row they represent 10, the row above 100, and so on.

3:06 Let’s say we have 3 heads of cattle represented

3:08 by 3 beads on the bottom row on the right side.

3:11 If we were to buy 4 more cattle we would just

3:14 slide 4 more beads to the right for a total of 7.

3:17 But if we were to add 5 more after the first 3 we would run out of beads,

3:21 so we would slide everything back to the left,

3:23 slide one bead on the second row to the right, representing ten,

3:27 and then add the final 2 beads on the bottom row for a total of 12.

3:30 This is particularly useful with large numbers.

3:33 So if we were to add 1,251 we would just add 1 to the bottom row,

3:38 5 to the second row, 2 to the third row,

3:40 and 1 to the fourth row- we don’t have to add

3:43 in our head and the abacus stores the total for us.

3:46 Over the next 4000 years,

3:47 humans developed all sorts of clever computing devices,

3:50 like the astrolabe, which enabled ships to calculate their latitude at sea.

3:53 Or the slide rule, for assisting with multiplication and division.

3:56 And there are literally hundred of types of clocks

3:59 created that could be used to calculate sunrise,

4:01 tides, positions of celestial bodies, and even just the time.

4:05 Each one of these devices made something

4:07 that was previously laborious to calculate much faster,

4:09 easier, and often more accurate–– it lowered the barrier to entry,

4:13 and at the same time, amplified our mental abilities–– take note,

4:16 this is a theme we’re going to touch on a lot in this series.

4:19 As early computer pioneer Charles Babbage said: “At each increase of knowledge,

4:23 as well as on the contrivance of every new tool,

4:27 human labour becomes abridged.” However,

4:29 none of these devices were called “computers”.

4:31 The earliest documented use of the word “computer” is from 1613,

4:34 in a book by Richard Braithwait.

4:36 And it wasn’t a machine at all- it was a job title.

4:38 Braithwait said, “I have read the truest computer of times,

4:41 and the best arithmetician that ever breathed,

4:43 and he reduceth thy dayes into a short number”.

4:46 In those days, computer was a person who did calculations,

4:49 sometimes with the help of machines, but often not.

4:52 This job title persisted until the late 1800s,

4:54 when the meaning of computer started shifting to refer to devices.

4:57 Notable among these devices was the Step Reckoner,

5:00 built by German polymath Gottfried Leibniz in 1694.

5:03 Leibniz said“...

5:04 it is beneath the dignity of excellent men to waste

5:07 their time in calculation when any peasant could do

5:09 the work just as accurately with the aid of a machine.”

5:11 It worked kind of like the odometer in your car,

5:13 which is really just a machine for adding

5:15 up the number of miles your car has driven.

5:17 The device had a series of gears that turned;

5:19 each gear had ten teeth, to represent the digits from 0 to 9.

5:22 Whenever a gear bypassed nine,

5:24 it rotated back to 0 and advanced the adjacent gear by one tooth.

5:27 Kind of like when hitting 10 on that basic abacus.

5:31 This worked in reverse when doing subtraction, too.

5:33 With some clever mechanical tricks,

5:34 the Step Reckoner was also able to multiply and divide numbers.

5:38 Multiplications and divisions are really just many additions and subtractions.

5:42 For example, if we want to divide 17 by 5,

5:45 we just subtract 5, then 5, then 5 again,

5:47 and then we can’t subtract any more 5’s… so we

5:50 know 5 goes into 17 three times, with 2 left over.

5:53 The Step Reckoner was able to do this in an automated way,

5:56 and was the first machine that could do all four of these operations.

6:00 And this design was so successful it was

6:02 used for the next three centuries of calculator design.

6:04 Unfortunately, even with mechanical calculators,

6:06 most real world problems required many steps

6:09 of computation before an answer was determined.

6:11 It could take hours or days to generate a single result.

6:14 Also, these hand-crafted machines were expensive,

6:15 and not accessible to most of the population.

6:17 So, before 20th century,

6:19 most people experienced computing through pre-computed tables assembled

6:23 by those amazing “human computers” we talked about.

6:26 So if you needed to know the square root of 8

6:28 million 6 hundred and 75 thousand 3 hundred and 9,

6:31 instead of spending all day hand-cranking your step reckoner,

6:33 you could look it up in a huge book

6:35 full of square root tables in a minute or so.

6:37 Speed and accuracy is particularly important on the battlefield,

6:40 and so militaries were among the first to apply computing to complex problems.

6:44 A particularly difficult problem is accurately firing artillery shells,

6:46 which by the 1800s could travel well over

6:49 a kilometer (or a bit more than half a mile).

6:51 Add to this varying wind conditions, temperature, and atmospheric pressure,

6:54 and even hitting something as large as a ship was difficult.

6:58 Range Tables were created that allowed gunners to look

7:00 up environmental conditions and the distance they wanted to fire,

7:03 and the table would tell them the angle to set the canon.

7:05 These Range Tables worked so well, they were used well into World War Two.

7:09 The problem was, if you changed the design of the cannon or of the shell,

7:12 a whole new table had to be computed,

7:15 which was massively time consuming and inevitably led to errors.

7:18 Charles Babbage acknowledged this problem in 1822

7:20 in a paper to the Royal Astronomical Society entitled:

7:23 “Note on the application of machinery

7:25 to the computation of astronomical and mathematical tables".

7:29 Let’s go to the thought bubble.

7:30 Charles Babbage proposed a new mechanical device called the Difference Engine,

7:34 a much more complex machine that could approximate polynomials.

7:38 Polynomials describe the relationship between several

7:40 variables- like range and air pressure,

7:43 or amount of pizza Carrie Anne eats and happiness.

7:45 Polynomials could also be used

7:47 to approximate logarithmic and trigonometric functions,

7:49 which are a real hassle to calculate by hand.

7:52 Babbage started construction in 1823, and over the next two decades,

7:55 tried to fabricate and assemble the 25,000 components,

7:58 collectively weighing around 15 tons.

8:01 Unfortunately, the project was ultimately abandoned.

8:03 But, in 1991, historians finished constructing a Difference Engine

8:07 based on Babbage's drawings and writings- and it worked!

8:10 But more importantly, during construction of the Difference Engine,

8:13 Babbage imagined an even more complex machine- the Analytical Engine.

8:17 Unlike the Difference Engine,

8:18 Step Reckoner and all other computational devices before

8:21 it- the Analytical Engine was a “general purpose computer”.

8:24 It could be used for many things, not just one particular computation;

8:27 it could be given data and run operations in sequence;

8:30 it had memory and even a primitive printer.

8:32 Like the Difference Engine, it was ahead of its time,

8:35 and was never fully constructed.

8:36 However, the idea of an “automatic computer”– one

8:39 that could guide itself through a series of operations automatically,

8:42 was a huge deal, and would foreshadow computer programs.

8:45 English mathematician Ada Lovelace wrote

8:47 hypothetical programs for the Analytical Engine, saying, “A new, a vast,

8:51 and a powerful language is developed

8:53 for the future use of analysis.” For her work,

8:56 Ada is often considered the world’s first programmer.

8:58 The Analytical Engine would inspire, arguably,

9:01 the first generation of computer scientists,

9:03 who incorporated many of Babbage’s ideas in their machines.

9:06 This is why Babbage is often considered the "father of computing".

9:09 Thanks Thought Bubble!

9:10 So by the end of the 19th century, computing devices were used for special

9:14 purpose tasks in the sciences and engineering,

9:16 but rarely seen in business, government or domestic life.

9:18 However, the US government faced a serious problem for its 1890

9:22 census that demanded the kind of efficiency that only computers could provide.

9:25 The US Constitution requires that a census be conducted every ten years,

9:29 for the purposes of distributing federal funds,

9:31 representation in congress, and good stuff like that.

9:33 And by 1880, the US population was booming, mostly due to immigration.

9:38 That census took seven years to manually

9:39 compile and by the time it was completed,

9:41 it was already out of date– and it was predicted

9:45 that the 1890 census would take 13 years to compute.

9:48 That’s a little problematic when it’s required every decade!

9:50 The Census bureau turned to Herman Hollerith,

9:52 who had built a tabulating machine.

9:54 His machine was “electro-mechanical”– it used

9:56 traditional mechanical systems for keeping count, like Leibniz’s Step Reckoner––

10:00 but coupled them with electrically-powered components.

10:02 Hollerith’s machine used punch cards which were paper cards with a grid

10:06 of locations that can be punched out to represent data.

10:08 For example, there was a series of holes for marital status.

10:11 If you were married, you would punch out the married spot,

10:14 then when the card was inserted into Hollerith’s machine,

10:16 little metal pins would come down over the card– if a spot was punched out,

10:20 the pin would pass through the hole

10:21 in the paper and into a little vial of mercury, which completed the circuit.

10:25 This now completed circuit powered an electric motor,

10:28 which turned a gear to add one, in this case, to the “married” total.

10:32 Hollerith’s machine was roughly 10x faster than manual tabulations,

10:34 and the Census was completed in just two

10:37 and a half years- saving the census office millions of dollars.

10:41 Businesses began recognizing the value of computing,

10:42 and saw its potential to boost

10:44 profits by improving labor- and data-intensive tasks,

10:47 like accounting, insurance appraisals, and inventory management.

10:50 To meet this demand, Hollerith founded The Tabulating Machine Company,

10:54 which later merged with other machine makers in 1924 to become

10:58 The International Business Machines Corporation

11:00 or IBM- which you’ve probably heard of.

11:02 These electro-mechanical “business machines” were a huge success,

11:06 transforming commerce and government, and by the mid-1900s,

11:09 the explosion in world population and the rise of globalized

11:12 trade demanded even faster and more flexible tools for processing data,

11:16 setting the stage for digital computers, which we’ll talk about next week.