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>> [THEME MUSIC PLAYING]

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DAVID J MALAN: Hello world.

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This is CS50Live.

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So it's been brought to my attention
that over the past few episodes

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I may have said a few
things that are incorrect.

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Well, among the first for instance,
was that this popular website

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we've been using for
the courses discussions

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is not in fact called Redder.

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It's apparently called Reddit.

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>> Meanwhile, it is the case that for quite
some time the United States was using

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00000000 to protect its missiles.

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However those missiles were nuclear,
and not apparently, "nuke-you-ler."

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>> Meanwhile.

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I love you.

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This is indeed currently,
supposedly, the most popular password

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right now for people to be using.

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But this-- if we zoom in-- is
not in fact how you make a heart.

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>> Lastly, CS50's own Shelley Westover,
whom you may remember from such films

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as this one, noted
that she is not in fact

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a camera "operater"
but a camera operator.

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Now speaking of camera
operators, the team

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has graciously allowed me
to borrow this camera today,

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so that we can take a
look at what's actually

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going on all this time
behind the scenes.

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So if you will, shall we go ahead
and take a tour of the studio?

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We're here in beautiful Hauser
Studio, in Widener Library.

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Against the backdrop here is this
green screen, otherwise known

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as a chroma-key, or cyc wall physically.

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And in fact, if I walk
up closely to this,

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notice how the ball has a slight curve
to it rather than a normal sharp angle.

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That allows us to keep
shadows off of the edges,

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and it also allows us to make
sure that we can superimpose

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almost anything we
want nice and cleanly.

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>> Now up here is a whole
bunch of lights controlled

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by a main panel of switches which
we'll see in just a little bit.

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Up here is an LED light with
so-called Barn Doors on it.

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This is what casts very directed light.

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Really gives me my glow during the show.

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And then over here we have a fluorescent
light, which casts softer light.

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Now both of these are
cheaper to operate,

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and a lot cooler to operate than
more traditional incandescent bulbs

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that a lot of folks still
tend to have in their homes.

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Now if we turn around here,
you'll see what I see.

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So we have a couple of our
cameras over here, one of which

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has a teleprompter on it.

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>> We actually don't really use
a teleprompter in CS50Live,

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but for the shorts, against those
white backdrops that you may recall,

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we actually use them quite a bit.

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Spending quite a bit of time in
advance scripting the material so as

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to get it just right.

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>> Now over here, you'll actually
see a camera up on the ceiling.

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Let's zoom in on that.

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That's the so-called bump
cam that gets those shots

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that you see at the very beginning
or the very end of CS50Live.

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And it's hard to see in
the lighting up there,

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but it's actually hung
upside down, and we're

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able to fix in software after the
fact by flipping it vertically.

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>> Now-- hi [? Andrea-- ?] over here,
let's head over to that light panel

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that I mentioned earlier.

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This light panel has a
whole bunch of switches,

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and they hate it when
I actually do this,

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but we can actually throw
some lights up and down here.

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I can't quite see the effect, but we're
kind of wreaking havoc on our cameras

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right now.

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But let's fix this.

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Oh boy, let's move on.

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>> So in here is the closet in
which all of the studios wires

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are ultimately routed.

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And this is sort of the
brains behind the operation,

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behind the scenes, huge fans in here.

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In fact, if I lean in you can
hear quite a bit of noise.

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So there's actually quite a
bit of insulation on these wall

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so as to keep that noise out when
we do in fact shut the doors.

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But way up there you can see all the
cables coming in and out of the closet.

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And over here you can see
a copy of the teleprompter

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that we saw just a moment ago.

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>> Alright, let's head into
the so-called control room.

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So over here, I still don't
quite understand this one,

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this is where we keep our
flammables apparently.

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But over here we have a
whole bunch of workstations

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where the CS50's team and
other HarvardX teams work.

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And over here we have our audio station.

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Let's take a look.

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Hey Patrick.

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So here we again have
a whole bunch of dials

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we can move up and down to
actually change the levels.

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This time for audio.

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And in fact, if I do this here-- I'm
going to slowly bring down this audio

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level, and I'm going to keep talking in
this usual voice of mine here in Hauser

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Studio for CS50 live, and at some
point you're not going to be--

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>> [VOLUME LOWERS UNTIL VOICE IS
 INAUDIBLE.]

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>> Now if I raise it back up you'll
start to hear my voice again.

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Now, you don't have to
do everything manually.

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In fact we have some presets.

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So if I go over here to the Layer
menu, I can actually toggle between 1

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in 16 and 7 in 32, and
you'll see this happen.

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Actually pretty neat.

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I do this quite a bit
as well-- watching.

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>> Anyhow, let's move over here and
you'll see a whole bank of hard drives,

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really.

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These are all SSD's that you might
have in today's laptops, and even

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some in today's desktops.

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And they store things like
this-- which is actually

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just a hard drive, which
is about 500 gigs in SSD.

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And you can see the
interface there via which

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it connects to the innards of that.

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This is where all of our
footage is ultimately stored,

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from one or more cameras that we
might be using for a particular shoot.

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>> Now over here-- Oh, Hey Ramon.

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Thanks.

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Ramon's never really given
me much attention there,

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but we'll just move on.

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If Ramon-- if I could take a look over
here, we have a whole bunch of buttons

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that we can play with as well.

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And meanwhile there's a whole
bunch of displays up here

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on two massive, big screens.

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And this is really like the
innards of a television studio.

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All of the video signals
come in here, and what

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we're able to do by touching the
switches and dials is actually

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produce a show in real time.

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So for instance, we have
this little throttle here,

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like you might see in a plane.

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If I start to gain this back, notice
what happens on the two images

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up there.

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Fading between the two, and so
we've gone from one to the other.

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And if I push that back up, now
we've got back the original images.

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>> Meanwhile this joystick over
here, like an old arcade console,

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allows us to do this with that bump cam.

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And there we go, there
we go, there we go.

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And now we have fixed that--
pretty much good enough

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for the purposes of the show.

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>> Now finally-- sorry Ramon-- we
also have some buttons here.

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DDR2, of my favorite games perhaps, and
if I hit this, we now get this effect.

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You might recall that from
episode two of CS50Live.

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If we push on title, this is what we
can hit if anything actually goes wrong,

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we're getting that screen there.

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And now lastly, I think it's
time for 60 seconds of Rob.

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Oh, son of a--

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>> [BASS GUITAR PLAYS]

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ROB: Oh, come on!

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Just use some animal video!

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>> [MUSIC PLAYS]

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>> [WOMAN SPEAKING JAPANESE]

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>> Recently in the news was
an article about CS50

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in a popular website
known as Life Hacker.

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Now one of your classmates, Annabel
from Australia, came across that article

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and in turn CS50 itself.

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She's now enrolled in the class
and she would like to say hello.

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ANNABEL: Hello world.

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My name is Annabel, and I'm
from Queensland, Australia.

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The reason I'm taking this class is
because I saw a post on Life Hacker,

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and knew that this was the key to
bridge the gap between being a newbie,

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and a future in CS.

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Taking this course will also be a bridge
in many directions for my autistic son

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who loves IT.

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I'm also hoping that
by the end to create

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programs to assist my dyslexic daughter.

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Currently I am an accountant,
with a heavy interest

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in technology, real estate,
gardening, and instrumental music.

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My name is Annabel, and this is CS50.

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>> SPEAKER: Allow me next
to introduce Betty,

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who would also like to say hello.

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BETTY: Hello, world.

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My name is Betty, and I'm
from southern California.

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I'm taking this course
because our society today

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seems to be geared towards programming.

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Programming is becoming
essential for our lives.

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And actually, I think it's
already essentially now,

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because a lot of the things that we
use have to incorporate programming

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in order for them to be created.

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Basically, we are going to be
geared towards a future filled

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with technology, and
programming is going

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to be an essential part of that future.

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So I think it's something
that's really cool,

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and that I should probably
get to learning it.

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So yeah, my name is
Betty, and this is CS50.

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DAVID J MALAN: Pictured
here meanwhile, is

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Raja from India, who has
gotten so immersed in CS50

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that he apparently had
it tattooed on his skin.

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>> And now, a tweet.

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This one from Carter in Virginia, who
wrote us with this-- "Consentino and I

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are making good use of my snow day
watching week one of Harvard's CS50

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on TV via Chromecast and YouTube."

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Who is Consentino?

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Well, apparently he's his cat,
but indeed, pictured here along

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with Carter's feet, is a big
screen TV in the background.

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And apparently there are
indeed using a Chromecast

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to project CS50's week one onto
that big screen TV wirelessly.

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Now Chromecast, if you're not familiar,
is actually kind of a neat device.

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It's a fairly inexpensive plug that you
can put into the back of your computer

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into an HDMI port.

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It has Wi-Fi access, and essentially
allows you to stream wireless

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content from your laptop onto
your TV, or even control your TV

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and download content like
videos directly to it.

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And now a note from Mohamed, one
of your classmates in Pakistan,

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who recently discovered
this curiosity-- apparently

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if you go to google.com
on occasion and search

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for me, David J. Malan, apparently
this guy comes up once in awhile.

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David H. Malan, who's apparently
a British psychotherapist who

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looks an awful lot like me.

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Now it turns out if you
click this feedback link

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in the bottom corner you can
actually report a problem,

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as things being wrong to Google.

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And let me-- since we
are on the internet

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here-- if you can help a guy out, and
actually click that wrong link up top,

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and just mention that David H.
Malan is not in fact David J. Malan.

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>> Now to be fair, there
probably is a David H. Malan,

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and he probably is a
British psychotherapist,

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so let's not report
anything else as wrong,

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but just that photo has probably
been chosen algorithmically

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incorrectly by Google's servers.

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>> And now a hello from CS50's
friend, Professor Harry Lewis.

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Professor Harry Lewis was actually
my own professor years ago

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when I took an intensive course
in Theory of Computation.

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A theory course in which you explore
the fundamental limits of computation,

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and exactly what computers
can and cannot do.

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We recently visited
Professor Lewis in his office

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to take a look at some
technologies past.

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PROFESSOR HARRY LEWIS: I'm Harry Lewis,
I'm a professor of Computer Science

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here at Harvard.

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I came to Harvard in 1964 as a
freshman, and except for three years

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off during the Vietnam War
I've been here ever since.

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So I now head the undergraduate
program in computer science,

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and I've taught lots of
different courses over the years.

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And I'd like to tell you
a little bit about some

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of the interesting things that
have gone on a Harvard, of which I

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have had some contact over the years.

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>> Her's my undergraduate
thesis, in 1968, which

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I wrote a two dimensional
programming language.

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This is a core memory plane, those
are a little magnetic doughnuts

236
00:11:36,555 --> 00:11:39,080
that are strung on the
intersections of wires.

237
00:11:39,080 --> 00:11:44,320
And this was the way memory
was done before semiconductors

238
00:11:44,320 --> 00:11:47,560
became a viable technology.

239
00:11:47,560 --> 00:11:52,900
This is a early 15 gigabyte
iPod, which I keep around

240
00:11:52,900 --> 00:11:56,200
not because anyone's impressed
with having a 15 gigabyte iPod,

241
00:11:56,200 --> 00:12:00,740
but because this is a 70
megabyte drive, and they

242
00:12:00,740 --> 00:12:05,820
went in disk drives that were
about the size of washing machines.

243
00:12:05,820 --> 00:12:07,820
So that was only 70
megabytes of memory, that

244
00:12:07,820 --> 00:12:10,359
gives you some sense of
how things have scaled.

245
00:12:10,359 --> 00:12:11,900
DAVID J MALAN: And now another tweet.

246
00:12:11,900 --> 00:12:13,820
This one from William
in the United Kingdom

247
00:12:13,820 --> 00:12:17,750
who wrote, "David J. Malan, after a bit
of Google stalking, it turns out Rob

248
00:12:17,750 --> 00:12:19,060
has a twin brother.

249
00:12:19,060 --> 00:12:21,830
Can we put him in CS50Live
and play spot the difference?"

250
00:12:21,830 --> 00:12:23,690
So William, this is indeed the case.

251
00:12:23,690 --> 00:12:26,660
CS50's own Rob Bowden
does have a twin brother.

252
00:12:26,660 --> 00:12:31,620
In fact, here is Rob and Paul--
or Paul and-- pictured here

253
00:12:31,620 --> 00:12:35,280
are two Bowdens, both of whom have
actually TFed for CS50 in the past,

254
00:12:35,280 --> 00:12:38,050
and indeed Rob is now on
CS50's full time team.

255
00:12:38,050 --> 00:12:40,510
>> Now, we too did bit of Google
stalking, and it turns out

256
00:12:40,510 --> 00:12:43,310
that twin brother Paul
has his own YouTube

257
00:12:43,310 --> 00:12:46,410
channel in which he fancies
himself a bit of a comedian.

258
00:12:46,410 --> 00:12:47,548
Let's take a look.

259
00:12:47,548 --> 00:12:49,940
>> PAUL BOWDEN: Hey guys.

260
00:12:49,940 --> 00:12:51,460
Paul Bowden here again.

261
00:12:51,460 --> 00:12:54,900
I'm back with my second try at stand up.

262
00:12:54,900 --> 00:12:58,910
Yes, I do know that I'm sitting down.

263
00:12:58,910 --> 00:13:02,810
The first time didn't go
as well as I had hoped for,

264
00:13:02,810 --> 00:13:05,840
but I took the advice
that you guys offered,

265
00:13:05,840 --> 00:13:10,290
and this time I'm going to be a little
less awkward, and a little better

266
00:13:10,290 --> 00:13:13,326
on the joke front.

267
00:13:13,326 --> 00:13:16,450
DAVID J MALAN: Now if you'd like to
subscribe to Paul's channel on YouTube,

268
00:13:16,450 --> 00:13:20,070
and you should, head to this URL here.

269
00:13:20,070 --> 00:13:23,390
Now brother Rob is of course
very proud of his twin brother.

270
00:13:23,390 --> 00:13:27,980
In fact, pictured here is Rob as
an animated GIF doing a fist pump.

271
00:13:27,980 --> 00:13:31,360
Now this has actually been circulated
on the internet quite a bit.

272
00:13:31,360 --> 00:13:33,240
So if you Google around
for this image here,

273
00:13:33,240 --> 00:13:36,110
you can even make this your
wallpaper if you would like.

274
00:13:36,110 --> 00:13:37,130
And you should.

275
00:13:37,130 --> 00:13:41,390
>> Now Rob here was cheering his
brother on in a popular American game

276
00:13:41,390 --> 00:13:43,232
show in which Paul was a participant.

277
00:13:43,232 --> 00:13:44,440
Now, what game show was that?

278
00:13:44,440 --> 00:13:46,148
Well we'll leave it
to you, the internet,

279
00:13:46,148 --> 00:13:49,210
to figure out exactly what game
show Paul Bowden participated on,

280
00:13:49,210 --> 00:13:53,140
and if you can find that out, let us
know at Facebook, Reddit, or Twitter,

281
00:13:53,140 --> 00:13:57,510
and we'll see if we can't show a
little clip in the next CS50Live.

282
00:13:57,510 --> 00:13:59,330
>> And now a piece of hardware.

283
00:13:59,330 --> 00:14:02,080
As you may have heard, CS50 in
some of it's on campus sections

284
00:14:02,080 --> 00:14:04,060
uses a piece of hardware
known as the Arduino.

285
00:14:04,060 --> 00:14:06,194
Pictured here for instance,
is the Arduino Uno,

286
00:14:06,194 --> 00:14:08,610
a little circuit board that
you can connect to a computer,

287
00:14:08,610 --> 00:14:11,010
and then actually program
it by writing C+ code,

288
00:14:11,010 --> 00:14:14,710
and then burning it into the hardware so
that it can actually execute programs.

289
00:14:14,710 --> 00:14:17,140
Now one of your classmates
here, Areor, decided

290
00:14:17,140 --> 00:14:20,110
to wire up an Arduino
Uno to his computer

291
00:14:20,110 --> 00:14:24,350
and then implement, if you can
believe it, Problem Set 2's Caesar.

292
00:14:24,350 --> 00:14:27,030
>> Now we don't have any audio in
this video, but let's zoom in

293
00:14:27,030 --> 00:14:28,755
and take a look at the end result.

294
00:14:28,755 --> 00:14:43,112

295
00:14:43,112 --> 00:14:45,570
Now if you are a Redditer, you
might have noticed this post

296
00:14:45,570 --> 00:14:49,290
a couple of weeks ago advertising
episode two of CS50Live.

297
00:14:49,290 --> 00:14:52,900
Now one of your classmates, Louis from
Montreal, Canada, after that episode

298
00:14:52,900 --> 00:14:55,556
kindly posted, "Wow,
that one was historical."

299
00:14:55,556 --> 00:15:00,600
Only to correct himself a few minutes
later with edit-- "hysterical, HA HA."

300
00:15:00,600 --> 00:15:02,410
So we'll take it either
way, but what was

301
00:15:02,410 --> 00:15:05,130
funnier than that, is that
Chris from Toronto, Canada

302
00:15:05,130 --> 00:15:08,290
then followed up with as
follows, "It would be hysterical

303
00:15:08,290 --> 00:15:12,670
if the next episode was historical as
a result of the production staff seeing

304
00:15:12,670 --> 00:15:13,490
this comment."

305
00:15:13,490 --> 00:15:16,800
Well indeed we did, and
now some more history.

306
00:15:16,800 --> 00:15:18,360
>> We pulled this up from the archives.

307
00:15:18,360 --> 00:15:22,700
This is in a magazine, Popular
Electronics, an issue from 1975,

308
00:15:22,700 --> 00:15:25,850
which bore this headline,
World's First Minicomputer Kit

309
00:15:25,850 --> 00:15:27,440
to Rival Commercial Models.

310
00:15:27,440 --> 00:15:29,050
The Altair 8800.

311
00:15:29,050 --> 00:15:31,940
Now at the time there wasn't
really a programming language

312
00:15:31,940 --> 00:15:35,110
with which you could make this
machine solve problems very easily,

313
00:15:35,110 --> 00:15:36,930
and so a young Harvard
student at the time

314
00:15:36,930 --> 00:15:39,810
named Bill Gates decided
with some friends of his

315
00:15:39,810 --> 00:15:43,700
to write the first interpreter for
programming language, known as basic,

316
00:15:43,700 --> 00:15:45,900
with which to drive
this piece of hardware.

317
00:15:45,900 --> 00:15:48,220
We took a stroll recently
with Professor Harry Lewis

318
00:15:48,220 --> 00:15:51,040
to Maxwell Dworkin, Harvard's
computer science building, where

319
00:15:51,040 --> 00:15:55,170
the source code for that original
BASIC interpreter still hangs.

320
00:15:55,170 --> 00:15:57,162
And we ask him if he
could give us a tour.

321
00:15:57,162 --> 00:15:58,870
PROFESSOR HARRY LEWIS:
What you have here

322
00:15:58,870 --> 00:16:03,780
is a listing of an
early piece of software

323
00:16:03,780 --> 00:16:08,470
written by Bill Gates and Paul
Allen, the founders of Microsoft.

324
00:16:08,470 --> 00:16:10,790
So the code is interesting
for two reasons.

325
00:16:10,790 --> 00:16:13,720
First of all it became
Microsoft's first product,

326
00:16:13,720 --> 00:16:20,080
which was an interpreter for
the basic programming language.

327
00:16:20,080 --> 00:16:23,190
And secondly, this was
one of the first attempts

328
00:16:23,190 --> 00:16:28,840
to create an interpreter so ordinary
people could use personal computers.

329
00:16:28,840 --> 00:16:30,900
So Bill Gates was an
undergraduate at Harvard.

330
00:16:30,900 --> 00:16:33,070
I started teaching at Harvard in 1974.

331
00:16:33,070 --> 00:16:38,390
This was done in 1975, so it was early
in his career and early in my career.

332
00:16:38,390 --> 00:16:42,040
I actually taught Bill in
a course around this time.

333
00:16:42,040 --> 00:16:45,380
Paul Allen was not a
Harvard student, but he

334
00:16:45,380 --> 00:16:49,200
had been a high school
classmate of Bill Gates.

335
00:16:49,200 --> 00:16:51,990
>> If you come and look
at the listing, you'll

336
00:16:51,990 --> 00:16:56,600
actually find a third name, Monte
Davidoff, who was Gates' classmate here

337
00:16:56,600 --> 00:16:57,500
at Harvard.

338
00:16:57,500 --> 00:16:59,600
OK, so here's an
interesting comment up here.

339
00:16:59,600 --> 00:17:05,400
It says, "In 4k can delete square
root but for loops should still work."

340
00:17:05,400 --> 00:17:11,310
OK, so what that means is that there
was two ways to compile this program.

341
00:17:11,310 --> 00:17:16,140
One was to run on a version
of this Altair computer

342
00:17:16,140 --> 00:17:19,339
that only had 4K words of memory.

343
00:17:19,339 --> 00:17:22,430
4,096 words of memory.

344
00:17:22,430 --> 00:17:28,020
But the big version had 8 K, and so
what this says is that in the 4K version

345
00:17:28,020 --> 00:17:31,030
you had to delete some
code to make it fit.

346
00:17:31,030 --> 00:17:33,050
And one of the things
that would be deleted

347
00:17:33,050 --> 00:17:37,960
would be the square root routine,
but apparently the for loops

348
00:17:37,960 --> 00:17:41,220
should still work, even
when you're compiling down

349
00:17:41,220 --> 00:17:46,150
for just the 4K version
of the kit computer.

350
00:17:46,150 --> 00:17:49,750
>> Now if you zoom in on that source code
you may have noticed a familiar name.

351
00:17:49,750 --> 00:17:52,280
Indeed, User Holloway
was the individual who

352
00:17:52,280 --> 00:17:56,282
printed this source
code in April of 1975.

353
00:17:56,282 --> 00:17:59,240
Now those of you who've asked questions,
perhaps on Reddit or elsewhere

354
00:17:59,240 --> 00:18:03,274
for CS50, might have come across Glenn
Holloway, one of CS50's team members

355
00:18:03,274 --> 00:18:05,440
who has actually been with
the course for some time,

356
00:18:05,440 --> 00:18:09,160
and very graciously offers quite often
to help students via the internet

357
00:18:09,160 --> 00:18:11,140
with any problems that they might solve.

358
00:18:11,140 --> 00:18:13,770
And indeed, it seems he was
doing that even in yesteryear

359
00:18:13,770 --> 00:18:16,320
when this source code
needed to be printed out.

360
00:18:16,320 --> 00:18:20,240
>> Now let's fast to present day, in
fact this is truly breaking news.

361
00:18:20,240 --> 00:18:23,577
Recently revealed was this project
tango, an initiative by Google

362
00:18:23,577 --> 00:18:25,660
and a number of other
companies to actually create

363
00:18:25,660 --> 00:18:28,830
software with which you can use a
phone or similar wireless device

364
00:18:28,830 --> 00:18:31,150
and walk around your
physical environment

365
00:18:31,150 --> 00:18:34,960
and actually make a 3D model of it--
which typically is incredibly time

366
00:18:34,960 --> 00:18:36,340
consuming and/or expensive.

367
00:18:36,340 --> 00:18:40,350
And yet, with today's technology you
might soon be doing this yourself,

368
00:18:40,350 --> 00:18:43,150
and you might soon be writing
software yourself with which

369
00:18:43,150 --> 00:18:44,930
to leverage this new technique.

370
00:18:44,930 --> 00:18:45,680
Let's take a look.

371
00:18:45,680 --> 00:18:49,530

372
00:18:49,530 --> 00:18:52,540
>> JOHNNY LEE: My name is Johnny Lee,
and I work in the advanced technology

373
00:18:52,540 --> 00:18:54,560
and projects group at Google.

374
00:18:54,560 --> 00:18:56,690
Our small team here,
based in California,

375
00:18:56,690 --> 00:19:01,200
has been working with universities,
research labs, and industrial partners

376
00:19:01,200 --> 00:19:05,220
to harvest the last 10 years of
research in robotics and computer vision

377
00:19:05,220 --> 00:19:09,260
to concentrate that technology
into a very unique mobile phone.

378
00:19:09,260 --> 00:19:14,100
We are physical beings
that live in a 3D world,

379
00:19:14,100 --> 00:19:17,690
yet mobile devices today
assume that the physical world

380
00:19:17,690 --> 00:19:19,820
ends at the boundaries of the screen.

381
00:19:19,820 --> 00:19:23,010
Our goal is to give mobile
devices a human scale

382
00:19:23,010 --> 00:19:24,665
understanding of space and motion.

383
00:19:24,665 --> 00:19:26,540
EITAN MARDER-EPPSTEIN:
This is going to allow

384
00:19:26,540 --> 00:19:28,480
people to interact
with their environment

385
00:19:28,480 --> 00:19:30,360
in just a fundamentally different way.

386
00:19:30,360 --> 00:19:33,330
We can prototype in a
couple hours something that

387
00:19:33,330 --> 00:19:36,070
would take us months
or even years before,

388
00:19:36,070 --> 00:19:38,670
because we didn't have this
technology readily available.

389
00:19:38,670 --> 00:19:41,760
>> TED LARSON: What happens if you
have all of these pieces in a phone?

390
00:19:41,760 --> 00:19:46,280
How does that change what a phone is?

391
00:19:46,280 --> 00:19:48,460
>> JOHNNY LEE: We have
created a prototype phone

392
00:19:48,460 --> 00:19:52,150
containing highly customized
hardware and software, designed

393
00:19:52,150 --> 00:19:56,600
to allow the phone to track it's
motion in full 3D, in real time

394
00:19:56,600 --> 00:19:58,120
as you hold it.

395
00:19:58,120 --> 00:20:01,840
These sensors make over a
quarter million 3D measurements

396
00:20:01,840 --> 00:20:05,980
every single second, updating the
position and rotation of the phone,

397
00:20:05,980 --> 00:20:09,760
fusing this information into a
single 3D model of the environment.

398
00:20:09,760 --> 00:20:12,625
>> CHRIS ANDERSON: We have a problem
called navigation indoors.

399
00:20:12,625 --> 00:20:14,300
And it's a solution to that problem.

400
00:20:14,300 --> 00:20:17,383
>> EITAN MARDER-EPPSTEIN: It tracks your
position as you go around the world.

401
00:20:17,383 --> 00:20:19,070
And it also makes a map of that.

402
00:20:19,070 --> 00:20:23,114
>> CHASE COBB: Imagine that you scan a
small section of your living room.

403
00:20:23,114 --> 00:20:27,250
And then are able to generate
a little game world in it.

404
00:20:27,250 --> 00:20:29,900
I don't know of any other
controller or gaming

405
00:20:29,900 --> 00:20:31,660
device that can do that at the moment.

406
00:20:31,660 --> 00:20:33,250
>> TULLY FOOTE: Putting
all this together, they

407
00:20:33,250 --> 00:20:35,041
pulled in experts from
all around the world

408
00:20:35,041 --> 00:20:37,360
and got them all working
on the same project.

409
00:20:37,360 --> 00:20:40,366
>> REMI EL-QUAZZANE: Those are
very high caliber of people.

410
00:20:40,366 --> 00:20:40,865
Why?

411
00:20:40,865 --> 00:20:42,302
It's very simple.

412
00:20:42,302 --> 00:20:44,782
I think, actually, people
that believe in the vision.

413
00:20:44,782 --> 00:20:47,240
JOHNNY LEE: Localization of
mapping is there on your phone,

414
00:20:47,240 --> 00:20:49,000
and you just use it.

415
00:20:49,000 --> 00:20:51,750
It's this ability to follow
in other people's footsteps.

416
00:20:51,750 --> 00:20:55,070
>> DIRK THOMAS: And we can also benefit
from what we do for the project

417
00:20:55,070 --> 00:20:57,258
back for the open source community.

418
00:20:57,258 --> 00:20:59,350
>> CHASE COBB: Use it for
the visually impaired,

419
00:20:59,350 --> 00:21:01,880
and give them auditory view
of where they're going.

420
00:21:01,880 --> 00:21:04,205
>> VINCE PASCUAL: Being
able to map your home,

421
00:21:04,205 --> 00:21:07,030
turn it around, let me see how
this furniture works in the room.

422
00:21:07,030 --> 00:21:09,580
>> EITAN MARDER-EPPSTEIN: Virtual
windows to different worlds,

423
00:21:09,580 --> 00:21:11,413
I mean the possibilities
are really endless.

424
00:21:11,413 --> 00:21:14,015

425
00:21:14,015 --> 00:21:16,890
JOHNNY LEE: Over the next few months
we will be distributing dev kits

426
00:21:16,890 --> 00:21:20,566
to software developers to develop
applications and algorithms on top

427
00:21:20,566 --> 00:21:22,572
of this platform.

428
00:21:22,572 --> 00:21:27,240
And we are just in the beginning, and
we know there's a lot more work to do.

429
00:21:27,240 --> 00:21:30,541
But we are excited about
where it is going to go.

430
00:21:30,541 --> 00:21:35,180
The future is awesome, and we believe
we can build it faster together.

431
00:21:35,180 --> 00:21:41,137

432
00:21:41,137 --> 00:21:43,970
DAVID J. MALAN: And now the moment
you've probably been waiting for.

433
00:21:43,970 --> 00:21:45,990
You may recall that
in the last episode we

434
00:21:45,990 --> 00:21:49,970
shared this tweet from CS50's own Andrew
Hill, who a few months back wrote us

435
00:21:49,970 --> 00:21:52,650
this, "David J Malan, where's my lamp?"

436
00:21:52,650 --> 00:21:55,690
Now since then a number of you have
submitted videos making your case

437
00:21:55,690 --> 00:21:59,120
as to why you should be the next
recipient of a CS50 desk lamp.

438
00:21:59,120 --> 00:22:02,650
We thought we'd share at first
one from Mohamed in Morocco.

439
00:22:02,650 --> 00:22:05,800
It turns out that Mohammed's birthday
was this past week, so allow me also

440
00:22:05,800 --> 00:22:10,050
on behalf of CS50 to say happy
19th birthday to Mohamed.

441
00:22:10,050 --> 00:22:11,996
Let's take a look.

442
00:22:11,996 --> 00:22:15,080
>> MOHAMMED: Hello, I am
Mohamed from Morocco.

443
00:22:15,080 --> 00:22:20,510
I am studying in another city-- which
is a little far from my original city

444
00:22:20,510 --> 00:22:25,390
where I am living with my family--
where I left my desk lamp.

445
00:22:25,390 --> 00:22:28,940
So I'm living in a dormitory
and this is my room.

446
00:22:28,940 --> 00:22:32,810

447
00:22:32,810 --> 00:22:37,440
You can see here that light is
yellow, and I don't really like it.

448
00:22:37,440 --> 00:22:39,250
I prefer the white one.

449
00:22:39,250 --> 00:22:43,350
That's why I want a CS50 desk lamp.

450
00:22:43,350 --> 00:22:47,109
You can imagine me sitting
there and working with it.

451
00:22:47,109 --> 00:22:48,900
DAVID J. MALAN: And
now another submission.

452
00:22:48,900 --> 00:22:52,700
This one Emad, a student
in his dorm room.

453
00:22:52,700 --> 00:22:54,680
>> EMAD: I'm Emad from [INAUDIBLE].

454
00:22:54,680 --> 00:22:56,605
So why do I want a desk lamp?

455
00:22:56,605 --> 00:22:59,760
First of all, it will act as
a moderate source of light

456
00:22:59,760 --> 00:23:03,380
for my studies of high school,
as I've just started fourth year.

457
00:23:03,380 --> 00:23:06,730
And as well as well as the
online courses, especially CS50.

458
00:23:06,730 --> 00:23:09,130
The most important
reason is that it will

459
00:23:09,130 --> 00:23:11,190
act as software for the course CS50.

460
00:23:11,190 --> 00:23:13,550
For example, if someone
comes in my home and asks

461
00:23:13,550 --> 00:23:17,720
how did you get that beautiful lamp, I
will tell them that CS50 class sent it.

462
00:23:17,720 --> 00:23:21,290
And so I spread the word of
CS50, and most importantly, I

463
00:23:21,290 --> 00:23:23,970
remember if for my life.

464
00:23:23,970 --> 00:23:27,460
I am Emad, and this is CS50.

465
00:23:27,460 --> 00:23:30,510
>> DAVID J. MALAN: And now Tim from
Malaysia, pictured here in the dark.

466
00:23:30,510 --> 00:23:31,220
Listen closely.

467
00:23:31,220 --> 00:24:19,030

468
00:24:19,030 --> 00:24:21,640
DAVID J. MALAN: And now a
family friendly film from Zevin

469
00:24:21,640 --> 00:24:24,336
in Vancouver, British Columbia.

470
00:24:24,336 --> 00:24:25,080
>> ZEVIN: Hi there.

471
00:24:25,080 --> 00:24:26,250
I'm Zevin Lennick.

472
00:24:26,250 --> 00:24:30,925
I'm doing EDX for CS50,
and we can't find our lamp.

473
00:24:30,925 --> 00:24:31,675
The house is dark.

474
00:24:31,675 --> 00:24:32,610
What do you think?

475
00:24:32,610 --> 00:24:34,530
>> SPEAKER 1: Maybe it's over there?

476
00:24:34,530 --> 00:24:35,385
>> ZEVIN: Are you sure?

477
00:24:35,385 --> 00:24:35,670
>> SPEAKER 1: Maybe.

478
00:24:35,670 --> 00:24:36,910
>> ZEVIN: Should we go find out?

479
00:24:36,910 --> 00:24:37,620
>> SPEAKER 1: Let's go.

480
00:24:37,620 --> 00:24:38,245
>> ZEVIN: Alright.

481
00:24:38,245 --> 00:24:42,030

482
00:24:42,030 --> 00:24:43,530
>> SPEAKER 1: Whoa, look at that light.

483
00:24:43,530 --> 00:24:45,540
>> ZEVIN: Maybe there's a lamp in there.

484
00:24:45,540 --> 00:24:47,129
>> SPEAKER 1: Let's check it out.

485
00:24:47,129 --> 00:24:48,420
ZEVIN: Do you want me to do it?

486
00:24:48,420 --> 00:24:49,535
SPEAKER 1: No, I'll do it.

487
00:24:49,535 --> 00:24:51,365
ZEVIN: OK.

488
00:24:51,365 --> 00:24:52,805
SPEAKER 1: Stay away from my lamp!

489
00:24:52,805 --> 00:24:53,305
Oh no!

490
00:24:53,305 --> 00:24:55,634

491
00:24:55,634 --> 00:24:58,050
DAVID J. MALAN: And now a
submission from Eggers in Latvia

492
00:24:58,050 --> 00:25:03,360
who really took things up
a notch with this film.

493
00:25:03,360 --> 00:25:05,180
>> EGGERS: (AS LAMP 1) Well, how you doing?

494
00:25:05,180 --> 00:25:07,250
>> WOMAN: (AS LAMP 2) Mmm.

495
00:25:07,250 --> 00:25:07,750
Hello.

496
00:25:07,750 --> 00:25:20,440

497
00:25:20,440 --> 00:25:22,170
>> EGGERS: (AS LIGHTBULB
1) This is awesome.

498
00:25:22,170 --> 00:25:25,260
>> WOMAN: (AS LIGHTBULB 2) Yes.

499
00:25:25,260 --> 00:25:26,782
Ooh!

500
00:25:26,782 --> 00:25:27,990
EGGERS: (AS LIGHTBULB 1) Ooh!

501
00:25:27,990 --> 00:25:30,323
EGGERS: (AS BABY LIGHTBULB)
[LAUGHTER] Where is my lamp?

502
00:25:30,323 --> 00:25:32,450

503
00:25:32,450 --> 00:25:33,920
>> EGGERS: Hi, my name is Eggers.

504
00:25:33,920 --> 00:25:35,927
And I am from Latvia.

505
00:25:35,927 --> 00:25:37,214
And this is--

506
00:25:37,214 --> 00:25:38,089
SPEAKER 2: Our study.

507
00:25:38,089 --> 00:25:39,466
Stay tuned.

508
00:25:39,466 --> 00:25:42,220
>> EGGERS: No, this is CS50.

509
00:25:42,220 --> 00:25:44,370
>> DAVID J. MALAN: And now,
last but not least, a

510
00:25:44,370 --> 00:25:48,520
submission from Phillip in Germany.

511
00:25:48,520 --> 00:25:50,436
>> PHILLIP: Hey there David, I'm Phil.

512
00:25:50,436 --> 00:25:52,635
I'm a student of cognitive
science from Germany.

513
00:25:52,635 --> 00:25:56,050
Cognitive science is a field
that studies the human mind

514
00:25:56,050 --> 00:26:01,410
and brain, joined from disciplines like
neuroscience, psychology, linguistics,

515
00:26:01,410 --> 00:26:03,270
and even computer science.

516
00:26:03,270 --> 00:26:07,120
Now last semester, I spent a
semester abroad at Harvard.

517
00:26:07,120 --> 00:26:10,030
And I also attended your course, CS50.

518
00:26:10,030 --> 00:26:13,850
>> Now while I loved CS50, I
never got my own desk lamp.

519
00:26:13,850 --> 00:26:18,340
Now I raised my hand in almost
every lecture in a desperate attempt

520
00:26:18,340 --> 00:26:21,405
to get me on stage and
receive my own CS50 desk

521
00:26:21,405 --> 00:26:25,510
lamp-- or even just a
fricking stress ball.

522
00:26:25,510 --> 00:26:29,530
Now I finally got my stress
ball at the CS50 fair,

523
00:26:29,530 --> 00:26:36,970
but I'm still suffering deeply from that
lack of a CS50 desk lamp in my life.

524
00:26:36,970 --> 00:26:41,930
So Mr. David Malan, my question
to you is quite simple.

525
00:26:41,930 --> 00:26:45,650
Where's my [BLEEP] desk lamp?

526
00:26:45,650 --> 00:26:47,540
>> DAVID J. MALAN: And
now a bit more history.

527
00:26:47,540 --> 00:26:50,270
You may recall the following
film from week one of CS50.

528
00:26:50,270 --> 00:26:56,450
>> [MUSIC PLAYS]

529
00:26:56,450 --> 00:26:59,320
>> SPEAKER 3 : A triumph of
mathematical and mechanical skill,

530
00:26:59,320 --> 00:27:03,170
as this great new automatic
calculator at Harvard University.

531
00:27:03,170 --> 00:27:07,050
Intricate problems in mathematics
put through the machine in coded form

532
00:27:07,050 --> 00:27:10,270
on tape are accurately
solved in a minute fraction

533
00:27:10,270 --> 00:27:12,790
of the time required
for human calculation.

534
00:27:12,790 --> 00:27:24,170

535
00:27:24,170 --> 00:27:28,485
Designed to expedite all forms of
mathematical and scientific research,

536
00:27:28,485 --> 00:27:33,610
the giant mechanical brain will work for
the United States Navy until war's end.

537
00:27:33,610 --> 00:27:42,745

538
00:27:42,745 --> 00:27:44,870
DAVID J. MALAN: Now the
Mark I is no longer in use,

539
00:27:44,870 --> 00:27:46,910
but it does still live here on campus.

540
00:27:46,910 --> 00:27:49,840
We decided to take one final
stroll with Professor Harry Lewis

541
00:27:49,840 --> 00:27:53,080
to take a closer look at Harvard's
science center-- new home

542
00:27:53,080 --> 00:27:54,350
to the Harvard Mark I.

543
00:27:54,350 --> 00:27:56,600
PROFESSOR HARRY LEWIS: So
we're in the Harvard Science

544
00:27:56,600 --> 00:27:59,950
Center, which is the crossroads
of the Harvard campus.

545
00:27:59,950 --> 00:28:04,180
A lot of the science departments have
their classrooms and offices in here.

546
00:28:04,180 --> 00:28:07,190
What's behind us here
is the Mark I computer,

547
00:28:07,190 --> 00:28:09,820
which was early
electromechanical computer.

548
00:28:09,820 --> 00:28:12,190
>> So the Mark I computer
is here at Harvard

549
00:28:12,190 --> 00:28:17,580
because Howard Hathaway Aiken, who was
the person who conceived and designed

550
00:28:17,580 --> 00:28:21,350
the machine in collaboration
with IBM engineers,

551
00:28:21,350 --> 00:28:26,220
was a Harvard professor
of applied mathematics.

552
00:28:26,220 --> 00:28:32,590
And he wanted to relieve the labor
of solving numerical equations

553
00:28:32,590 --> 00:28:36,820
by mechanical calculation that
was done on pencil and paper.

554
00:28:36,820 --> 00:28:39,930
>> What we have here is
actually only a chunk of it.

555
00:28:39,930 --> 00:28:43,820
It was 51 feet long and when
it was all in one piece.

556
00:28:43,820 --> 00:28:49,730
It could do three additions per second,
a multiplication took six seconds,

557
00:28:49,730 --> 00:28:53,110
and a division took 15 seconds.

558
00:28:53,110 --> 00:28:57,870
So this was a huge advance over
doing things with pencil and paper,

559
00:28:57,870 --> 00:29:02,870
but it was slow work, and keeping
the machine going all the time

560
00:29:02,870 --> 00:29:08,670
was a major feat of electromechanical
engineering expertise.

561
00:29:08,670 --> 00:29:12,100
>> It was used for ballistics
calculations, for calculating

562
00:29:12,100 --> 00:29:15,120
the trajectory of missiles.

563
00:29:15,120 --> 00:29:19,050
And it was also used for a little bit
of the calculation in the Manhattan

564
00:29:19,050 --> 00:29:25,470
Project for determining the right
parameters for the atomic bomb.

565
00:29:25,470 --> 00:29:29,230
>> So what you see here
are paper tape drives,

566
00:29:29,230 --> 00:29:33,550
so the program was punched in
paper tape and was on a loop.

567
00:29:33,550 --> 00:29:36,820
What you see there are
registers that would

568
00:29:36,820 --> 00:29:42,060
correspond to the stored memory of the
machine, which was only used for data.

569
00:29:42,060 --> 00:29:44,480
The program itself was fixed.

570
00:29:44,480 --> 00:29:47,460
These electric typewriters
were used to print the output.

571
00:29:47,460 --> 00:29:51,220
These dials, which
have 10 positions, are

572
00:29:51,220 --> 00:29:53,120
where you would insert the constants.

573
00:29:53,120 --> 00:29:57,990
So the program was fixed on paper
tape, and if you had a constant,

574
00:29:57,990 --> 00:30:03,360
like you have in C+ code-- you set some
variable equal to 47 at the beginning

575
00:30:03,360 --> 00:30:05,950
of your program-- this
is the equivalent here.

576
00:30:05,950 --> 00:30:10,910
You would dial in the number
47 using these registers.

577
00:30:10,910 --> 00:30:14,460
>> The computational equivalent
of this is much less

578
00:30:14,460 --> 00:30:22,055
than the smallest wrist watch
computer that is now being produced.

579
00:30:22,055 --> 00:30:23,680
DAVID J. MALAN: That's it for CS50Live.

580
00:30:23,680 --> 00:30:25,471
Thanks so much to this
week's contributors,

581
00:30:25,471 --> 00:30:27,550
as well as to this week's
team behind the camera.

582
00:30:27,550 --> 00:30:30,050
Let's close the show with
a look at a scratch project

583
00:30:30,050 --> 00:30:32,040
from Lisa Chung in Boston,

584
00:30:32,040 --> 00:31:41,227
>> [MUSIC- YLVIS, "THE FOX"]