>> Sean: We have had some questions in from some
of the fans, some of the viewers of Computerphile
And we thought it would be a be nice idea to have a
chat and you tell us what you think. So, I've
picked a few [questions] that maybe hopefully will
go together and and we may well do some
others at another time. We're going to kick
off with this one here from Patrick Orton,
who I think you may actually ...
>> DFB: Yes! Hi Patrick! He was one of my project
students a year or two ago. Yeah! Hi Patrick!
>> Sean: He's asked four questions. So we'll whip
through these before getting on to some others.
So: what is your favourite area of
computer science ?
>> DFB: my favorite area of
computer science? Well, it's 
split into two really. Although it's very
very applied computer science I really
do like everything to do with digital
documents - right through from the sort of
XML structural stuff right down to the
nitty gritty typesetting, fonts and
PostScript stuff. I love that. But if you
were to say is there an area I like
doing videos on which fascinates me
- although it's not really my specialist
area - the answer is, what we're doing at
the moment, which is Regular Expressions.
I think they're fascinating! They're so
easy but so difficult. You get Regular
Expression wars between commenters.
They're wonderfu!lThere's a way to go
yet on REs before we finally say
"That's enough!" Yeah, 
>> Sean: well, it's interesting
because you kind of roll these first two
questions together, so we'd ask the favourite
area to work in and the area you're most
interested in. What's the area of computer
science that you'rer best at?
>> DFB: Do you know that's a very good question 
Patrick. I can tell you are one of the
students that I supervised. How well you 
know me! The answer, truthfully, is that I
don't consider myself an outstanding
computer scientist in any of the areas.
I suppose you could say, insofar as I have
some expertise, the whole digital
documents / electronic publishing,
low-level, PostScript/PDF stuff, yes.
But actually what am I really best at? It
finally dawned on me, and thanks to you
and Brady, you have given me the ability
to exploit this. I'm best at explaining
things to people and, as I've often said,
I, when I was younger, had to teach myself
and there's [potentially] a whole extra episode on why, 
to be competent in a wide range of things.
And being forced to teach something is the
best way to learn it. So I think I am
good at that. The problem I had was if I
was like Brian Kernighan and had the
tenacity to write lots of books, that
would have been a way to propagate my
expertise. I don't really have the
patience to write books. What I wanted
was somebody to come and just talk to me
and make videos from my waffle! And you
and Brady - honestly I remember that first
visit, and it's been solidly downhill for
seven years ever since then, hasn't it?
2013?  something like that yeah?! 
>> Sean: Patrick also had a question, which connects 
to a couple of other questions, so I'm going to roll
these together if that's all right with you.
What is the area of computer science
that looks to be most important in the
near future?  which connects to one
Richard Denton's asked about " ... your
extensive history in the new field of
computer science, what direction is it
heading in and Gregor who said: " ... which
area of CS will in the near future be
used the most and which do you think
there's no future to?
>> DFB: I'm not very good at futurology! 
I could list all of the
things which I've come across in
computing and have said " ... that will *never*
catch on!"  But then, six months later, it's 
the lead
topic in the whole field! Now I think, all
right, let's just say recently the thing
this has quite taken my breath away has
been the whole stuff about Neural Nets
Deep AI and so on. And now it's fascinating 
because ... I'll tell you what is the
most fascinating thing. You had Deep Blue
playing chess basically by brute force
methods [looking mny moves ahead] and back in 
the 80s -- I don't play chess by the way but I 
do find it fascinating -- 
it was Deep Blue, IBM's Deep
Blue, I think, that defeated Kasparov for
the first time, Wow! you know. And I felt: "Well
it's just brute force and ignorance that [is]"
But on the other hand the moment you
start doing neural networks, which 
learn and adapt and once you start
feeding in the fact that you can play
yourself in a computer rendering of the
game. You know what they've done on GO
and chess and all that, now, is to say we
don't just hard-code the rules and
look thirty moves ahead. We'd get it
to find out what unlikely things have
come up, in me playing myself, where it
just went berserk and went off on a tangent
And I thought " ... that's a lost game" But it
wasn't! It found a back-door way in and
triumphed. And I think that's what took the
GO guy - was it Lee Sedol -  apart.
He just thought:" ...  that's ridiculous I'm gonna
win this one!" Then, about 20 moves later
he hadn't! And I think he found that
shattering, and I can well imagine that.
And I think my understanding is very
limited of this - is that the Deep Mind
people have now started applying all
that they did to GO to apply it back to
chess. And don't use brute force just
build up millions of games and let it
learn what's a good thing to do. And I
think I'm right in saying that that
piece of software, using the neural net
statistical whatever, is now more
successful than the original Deep
Blue was, but I'm not sure. So what you
can say is [that] taming big data via AI 
is a tremendous area. It's I mean Big
Data is important and the degree to
which you can tame it with so-called
AI is fine but the big question still is [this].
You go to the authors of these 
"highly intelligent" programs but they're not - 
and you say: "Can it do 'common sense' ? "
"No! not a hope! it's brilliant at go
because it's still a narrow and
well-defined field but don't ask it to
pontificate on the state of politics in
the Western Hemisphere". It hasn't a clue! So,
there we are, right, something that I know
I'm interested in. I know very little
about but does seem to me to be a real
marker for the future.
>> Sean: Maybe onto a different subject. 
We had a question from
Erik Stens and he said: "As engineers we
all have our pet project. What have been
some of your hobby projects - computer 
related - that you're most proud of.
And would you tell us a bit about them all?
>> DFB: Right! Well, I suppose I should say at the
start that one of the advantages I've
got being the ripe old age I am, is that
I've been what's called an Emeritus
Professor for well over ten
years now and that this does give me the
ability to pursue lunatic things that
would never ever have got me promoted
to Professor but I was there already.
>> Sean: can you tell people what 'emeritus' means 
For those who don't know those who aren't in academia?
>> DFB: What happens with Emeritus Professors is that
it's basically a way of pension ah--you
off but in a gentle way. The idea of an
Emeritus Professor - the Latin of course
means 'E' = 'out of 'merit. i.e. "because of merit"
You are given this honorary position. It
varies very much as to which university
are in as how active an Emeritus you
want to be, but for me, back in 2005,
I came off the regular payroll
as a professor and 'cut a deal', as it were,
where I will be brought back on a
renewable yearly contract to do fill-in
teaching on stuff I likeds but the good
thing was: " ... with no major administrative
responsibilities". So I took my pension I
got some extra top-up from the School of
Computer Science and really, I think, the
last actual taught course I did, given 
that I formerly 'went Emeritus' in 2005,
I was still teaching classes
through to 2013. And why did I change
tack then? Well, once upon a time, two hirsute
guys came into my office and said:
"Hello, we're Brady and Sean. We're going
to reshape your future" you've wanted to
find somebody idiotic enough to record
your waffle?
That's us!  Well, it's true isn't it ?
I always love the teaching but to be able
to teach in a way like this - which would
never have got me promotion to anything
had I tried to do it as a 30-year-old,
you know. Which is why, in many ways, I'm
so glad that Steve {bagley] and Mike {Pound] are 
still happy to do it because it can be part of
what you do but it can't be the totality
of what you do. And yet, for me now, it
really is almost a totality of what I do.
You've given me an avenue to spread the
gospel or something. Yeah! so that's what
it means to be an Emeritus Professor
It's given me complete freedom to do, for
example, the stuff we did rescuing the
banned paper [memorandum] about the Linotype 
202 typesetter. Now, it was such a good
project because it was Brian Kernighan's 
work - [he's] virtually a Computerphile
regular now although the [corona]virus has
confined him to the States for the moment -
but yes it was his work way back in the
late 1970s
which had been banned from publication. 
A mutual friend of both of us, Chuck
Bigelow who's the co-designer of the Lucida typefaces.
[He] basically said, to both of us, we know him
well. He said: "You two you should be
telling the story now - it's not sensitive
any more". So we did all those videos on it.
But in order to get the story total I
said to Brian: "What we have to do is
not just resurrect this memo, which was
on yellowing paper that had been
photocopied in 1978. We've got to
recreate it using modern PostScript/PDF
fonts technology at the quality that was
innately there off the virgin-fresh
bromide that came out of the 202. And
it's got to be really good and Postscript's
up to the job, you know, that is the the
glue that binds it all together we can
we can do it but I wanted it to be a
perfect resuscitation as it were. And
getting that last few percent right was
just very rewarding, but very frustrating.
I mean we had it published. It's had very
good reception. People love it when 
they find it. But could I seriously have
beem on the end of a yearly [personal] review
having to say this 'caper' that we did: does
that count towards making me a Professor ?!
I I think my previous heads of department 
would have said: "No! it's frivolous!"
>> Sean: It's interesting because it kind of leads
on too many other questions which is
from Jonathan Lystrom, I hope I'm
saying that right: "Ask Professor
Brailsford how he learned to be so
pedagogic well-versed and an absolute
joy to listen to". That's going to be nice
to hear. I assume I'm saying 'pedagogic' right? 
>> DFB: I think you are. Well, thank you for
the implied flattery - is it Jonathan?
Thank you. The thing is, of course, that my
style doesn't appeal to everybody.
Some people find it too waffly, too 'hand 
wavy', and although I love explaining
things to people I just love it when I
get real experts come at me - just the odd
one - and it's always: "David, you did a
good job. But you were on thin ice! You
very nearly started telling things that
were all flatly untrue. And I thought, I
thought, this is it! He's gonna fall down
into the ice-pit ...  at the
last minute, Oh! you know you rescued
yourself! You didn't tell an untruth but
it's not the way to explain it!" 
To which my retort is: "If I get people saying 'I
didn't remotely understand it until  [you]
explained it [your] way' ", then I rest my case
I was new I enjoyed teaching but the
answer is very simple when we were
turning from a Computer Science Group in
a Maths Department, this was in 1986, to
being a full-fledged Computer Science
department eventually, it didn't dawn on
me - because I was leading the charge on
this - that we'd actually have to teach
across the whole range of Computer
Science. So we took a first few Single
Honours computer science students in
1986 and then it suddenly hit me that, by
1989, we'd got to give them a full-blown
Computer Science experience. And how many
people did I have? Six  and that includes one technician 
and a pet cat [joke]. "Oh my lord, how are we gonna
do this?" And I said to people, I remember,
[at] one of the first departmental meetings,
I remember saying: "Look, we are very very
short-staffed. I think that the University
will help us out with one or two [extra academics] but it
won't be as many as we need: Sorry folks
we've all got to be prepared to teach
well outside our comfort zone!" 
And that is the answer to the real question [which] is:
"Why can you teach over such a broad range?"
I had to! I had to learn about
Chomsky, Regular Expressions, Turing
Machines and all that because at the
time I didn't have specialists to teach it
But it comes back to the main thing: I enjoy
teaching difficult things just by saying:
"I found it [this topic] difficult, here's how I got to
grips with it" And if that style of
explanation suits you then it's a
win-win situation.
>> Sean: We've had a question from a very
familiar name here, Graham Hutton. Have
you heard of this character?
>> DFB: Well, yes,you know it 'rings a bell' (!)
>> Sean: If you could have invented one idea in computing what
would it be?" 
>> DFB: Again first obvious answer is :
... would it have been invention or would it
have been 'discovery'. Was it in some sense
'there already'? I have often thought about
this but the the stuff I would love to
have been more involved in, I would love
to have been at the right place to be
heavily involved in it: In the early
60s to late 70s - it was over a long span
is the whole area of Chomsky Types 3 anbd 2
which covers, really regularexpressions, 
[plus a single stack]  when do they run out of steam?
What theorems can you prove about them?
Now it's an area that we're
still coming back at, but the one person
- sorry to be boring; everybody venerates
him for different reasons, still with us
and I reserve the right to come back and
do a biography of him, in some sense, from
my knowledge of him: Ken Thompson.  I mean
there were Regular Expressions invented
by Stephen Kleene and, yes, they were
fine but not a lot of people understood
them. But one of the people who really
understood them was not a sort of avowed,
declared, theoretician but .... Ken Thompson -
the world's ultimate super-duper
computer [system] programming practitione.
He just understood in a very very deep way
what a Regular Expression could do,
and couldn't do. And, more to the point.
there was a very important theoretical
paper by Dana Scott and Michael Rabin which
basically said: "These Regular Expressions
give rise to automata diagrams, which
we've done [on Computerphile] but of course, a lot 
of these automata diagrams basically say:
"Well, what's the next character in your input
stream? A  letter 'a' ? Oh! I can go in three
possible directions [in this automaton] on an 'a' 
Which one do you want me to take?" And the trouble is,
if you guess wrong, you end up down a
blind-alley. And you have to backtrack
out and you have to re-do and put back
again every variable you set in trying
to analyze it. You've got a reset and
that's massively expensive you see.
So, what Scott and Rabin did was to prove
that everything that was
non-deterministic could - by an
algorithmic process be turned into
a deterministic [one]. Except it might have a lot
of extra states and it might have a lot
of extra escape chutes labelled 'empty'
that took you down to a false ending.  and
you had to build to cope with that . Ken kind of
instinctively understood that, you know.
the idea that you could make it
deterministic. This is what Lex does for
those of you who are into using UNIX
tools. And I was just appalled and amazed
that that was possible. I thought I'd
love to have done that but I would have
loved [also] to have had Ken's sure-footedness.
In his favourite editor, QED,
he built in the whole deterministic/
non-deterministic thing. In ordinary UNIX
'ed' he decided that the labour involved
wasn't worth the candle, you know, and he
quite happily a- nd what better programmer
to do it - said [that] at times, although
recursive backtrack is deprecated, a
little bit of it - so long as you don't do
too much - I know how to do it.
And he was just such a master programmer
he could make it work either way.
