Even with all the time given up to me now by lockdown
there still isn't enough time. it takes for ever... !
And it's a good job i'm semi-retired from
being a part ofthe School of Computer Science at [University of] Nottingham because
honestly, as a regular employee, I could not justify
the hours i've spent on my latest ultra-fascinating project.
I refer you, my dear Watson, to the strange case
of Dennis Ritchie's missing thesis. We all know who Dennis is. UNIX was
invented by Ken and Dennis: Ken Thompson and Dennis Ritchie.
If you want to simplify things Ken was sort of in charge of UNIX the
operating system. [But] anything to do with creating C language
facilities and C compilers because, remember, UNIX was one of the
very first operating systems to be written in a specially invented
high-level language called C. And Dennis was an absolute whiz
with the C compiler, And it needed both of them to do this,
So, again, many of you will know Dennis because
one of the best-selling computer programming textbooks of all time
is "The C Programming Language" by Dennis Ritchie
and our good Computerphile colleague and friend
Brian Kernighan. There's some big gaps in our knowledge about
Dennis and I should remind you, I think, sadly, he died in 2010 [Correction: October 2011]
and he has been must much missed in the 10 years or so since that.
But recently the Computer History Museum (CHM) in the USA
came up with a story which just amazed everybody. People who knew him said:
"Yeah! Yeah! he went to Harvard and we think he did an
Applied Mathematics degree. So of course he was Dr
Ritchie wasn't he? He did a PhD ? Well the answer is he
studied for a PhD but it never properly got submitted.
The Examination Panel was appointed; they never met.
And the CHM story, basically, says "We don't totally
feel happy about this story... " The cover story is that
there was a standoff and that there was a need
to submit bound library copies of his thesis.
Dennis objected to having to pay to have this done. He thought he
made enough sacrifices already (presumably) in keeping himself alive
while he did his PhD thesis. It's worth saying his PhD was a very
theoretical one. In coming out of the Maths department,
perhaps not too surprising. But he regarded his thesis as something to be
got out of the way. But he was far more
interested in playing Space Wars and writing
real (prototype) C programs that were useful to help out Ken
his new-found friend, you see. I know you'll all say: "You [seem to] know everybody,
Don't name-drop !" [But], yes, i have to confess I did meet Dennis
Ritchie once. It was in 1986. Brian had been over to see me in the
early 80s. I paid a return visit to Bell Labs
i had a very enjoyable lunch: Dennis Ken, Brian and me, in which Ken regaled
us with his story about [how], if you were a qualified pilot
you could get to fly a MIG in Russia, if you played your cards right. They [in Russia] were so
short of foreign currency, foreign exchange, at
that time. [So] any gimmick that brought in tons of dollars, you see, was
absolutely fine. So, yes, i did meet Dennis just that once
and ... totally charming guy. It takes one to spot one [but] he was a computer scientist!
And so was Ken. They were so similar to each other but
so different, you know. They had this wicked way of answering
exactly what you'd asked not what you wish you'd asked.
Ken didn't get a PhD but he did enroll for a Masters [degree], Ii think,
at Berkeley and got that. So he was known about.
But everybody just assumed that Dennis must have got his PhD from Harvard
There were no hitches? Turns out there were!
And Bell Labs were not pleased to find that this person they'd
appointed, who they knew was good. They chased
after him as solidly as they chased after Ken.
I think they were tipped off how good he was but
to find suddenly ... I think it was somebody from Bell Labs who wrote to Harvard and said:
"What is going on ?" When will Mr Ritchie get his PhD.
And they got back the frostiest reply you will ever see,
effectively saying: "We have no plans - nor are we likely to have any plans -
to give Mr Ritchie a PhD ... " He had upset somebody mightily
and neither I, nor Brian nor his [Dennis's] brother Bill,
still we don't know the true story. Maybe we never will.
1967 was a long time ago, even for me. Just think of that - I was only 23 !
It's like back in the Jurassic, you know.
And just to put things absolutely clear, What would have been available to Dennis
for his output medium for his thesis? Really something like a clattery
Model 37 Teletype were becoming available [at that time].
They had a fixed character set; you couldn't
sort of extend it in any way. But they were very good [for medium quality]. i mean, you could have a
Teletype plugged in [to your computer] They were used in Stock Exchanges
so they were a common currency [computer peripheral]. So, you could plug a Teletype into your computer.
>> Sean: So, this thesis does exist then - it did exist?
>> DFB: It did exist, you see. His sister Lynn, who I think died
two or three years ago, was very fond of her brother and
looked after him carefully. She had a copy of his finally submitted thesis.
One of his fellow PhD students also from Harvard,
Albert Meyer, quite a name in theoretical computer science but of course,
again now, he'll have retired. He had one and
the other one, if you like, was Dennis's own working copy.
which eventually got submitted - or was about to be submitted. Normally, at this
period, what you would do was handwrite all your great thoughts and hand it to a
[technically trained] typist. The idea of being able to do it on a
computer and with computer assistance was at its very very infancy.
We have a copy here of what it was like. It could have been submitted [but] it didn't get
submitted. But Dennis decided, quite rightly, that
a Teletype terminal wasn't powerful enough because it didn't have enough
characters. So if you're going to either hand type it,
or typeset it from a peripheral stuck into
a computer, what were your options? Well, your options
were either an ultra-expensive, very early,
photo-typesetter [with] font characters as photos on a
film strip. So, your a - z were 26 different little
bits of film, probably wrapped around a drum that you
could illuminate from behind. Massively, massively, expensive. Even Bell
Labs hadn't invested in one of those at the time.
Although a few years later they did so. If you come back from those
rarified heights you could type it by hand
and if it was an old-fashioned typewriter you had special characters on
little things that look like nail-varnish sticks [Typits]
that you put into the throat of the typewriter
and you hit any key. And it was like a sort of
relayed impact. That alpha character [say] was actually
typed [as] 'i' or something, any character would do And it hit
the back of this special gadget and you got,
at the right place, the letter alpha. But going beyond that -- because that was a
pain -- IBM came up with the idea of a golf-ball typewriter.
[IBM video of Selectric in action] "This is the best thing that's happened to typing since electricity".
"The IBM Slectric typewriter." They are miraculous things,
unbelievable. What they did was that, instead of having
26 different dipsticks [Typits] for weird characters
they would put put them on, let's say, a Greek characters golf-ball
[So] for special purposes you take out your regular golfball, you plug in a Greek
characters one. When you look at the way that they
[IBM] embedded those metal characters onto the surface of a sphere,
in such a way that if the sphere rocked
ever so slightly, another row of characters became
as it were 'normal' to the paper and could be hit.
>> Sean: With a typewriter you can have little arms with a metal
kind of thing that gets .... >> DFB: at the end and they all end up in the
neck, or the throat, or whatever it's called and
on a conventional typewriter you move the sheet around [to place the characters]
With a Selectric you only move the sheet for line feeds forward and back.
You didn't move the sheet for horizontal motion(s).
This unbelievable cradle with a golf ball in it,
going seemingly at the speed of sound was leaping all over, left and right,
putting in characters. It is an electro-mechanical marvel of the
first order. And it did not come cheap! It cost as much as ...
well the story at the time was -- those of you on the far side of the Atlantic can
translate this better than me -- it cost as much as a Buick. Now a Buick
is not an utterly luxurious saloon, I don't think,
But it's not cheap! And it certainly wasn't cheap
in those days, So it [a Selectric 2741 peripheral] cost as much as a medium-sized saloon car,
just for this output device! And Dennis having been taken on by
Bell Labs as the 'bright new lad', actually conned them into letting him
have an online version of one of these devices
it's called a 2741 and [it also had] a dedicated [telephone] line that
had a monthly rental at eye-watering prices.
just so that, as well as working for Bell Labs in his new job,
he could also have a golf-ball machine down there [in the basement of the Ritchie family house]
where he did experiments on how to typeset his thesis properly.
And brother Bill (We'll point to his Web site -- https://dmrthesis.net) aged nine [Correction: twelve] years old, at the time
was just in awe of Dennis sitting in their basement
(in the Ritchie family house). Dennis rented the basement, just
swapping golf balls and messing about with this thing [which was] in
one corner of the basement, from what I understand.
But, even so, how did he, in the end, manage 180 pages of thesis
with changes of characters all over the place?
>> Sean: Because we're talking about [essentially] typesetting equations here aren't we?
>> DFB: yes, I'd probably better turn our attention
to this one I think [points at equation on hard-copy printout] which is pretty horrifying. I mean when
you look at it there are the obvious alphabetic
characters there. But at the moment, inked in, is
a Greek 'rho', or is it a 'p' symbol in Dennis's own handwriting. And just the
sheer density of this stuff, one [equation] on top of another.
A funny thing there which is a 'monus' operator.
So, this is horrifying to contemplate
is: "How many golf-ball changes would you need
to typeset that page?" Because what you've got to do is do all the easy stuff - and
there isn't much easy stuff here - set it [the golfball carriage] back, in a
sense, to a 'home' position and put the paper back in again.
In other words, if it's on tractor feed, make sure you get back to exactly the
right start position, then go through it [the document] waving the golf ball
around on its carriage and then deciding:
"Ah!, I'm needed there. Let's type one character there." So, you might end up
having to do multi-pass processing on just about every page, depending on complexity.
Now some of you may remember we did
- actually you may not even recognize it
as a comparable exercise. About 6 or 7 years ago we did [on 'Computerphile] a thing about the
Vacation Memo. It was a 13-page [Bell Labs] memo
of the fights they [Bell Labs] had had with Mergenthaler, and with the [202 typesetter] hardware,
to get everything working. But they succeeded in the end. We effectively wanted
to do, for Dennis's thesis, what we did in
rescuing the Vacation Memo. The trouble is it's not only ten times
longer, is this thesis, it's also easily ten
times harder to do, because his material is so complex.
[For] the stuff on the 202 we were rescued by the fact that
fonts carried on beyond the 202 [into laser-printers] [and] into the great new world of Adobe Type 1 [fonts],
Truetype fonts, Open Type fonts for those of you into these things.
There are standards. You can miss out all the [electro-mechanical] stuff in the
middle take a flying leap into the world of fonts And things become
easier fortunately. How do we make our flying leap here?
Here is a font, if you care to call it that, which basically
exists on a golf-ball on a typewrite.r Not a traditional conveyance mechanism
for what a typographer might call a 'real font'.
Nevertheless, our good friend Chuck Bigelow,
typographer and giant of the Lucida typeface family,
when advising us said: "i'll have a look around and see
if somebody has seen fit to turn the Selectric font
into what we would call a 'proper font' " And he found for us
from the Bitstream foundry, a font which I think is called Pica 10 and it's
pretty darn close to what a standard Selectric golf-ball has got.
But unfortunately nobody did the exotic symbols [e.g. Script, Greek, Math - all at fixed pitch].
And the thing about the main running text is that because it came off a
typewriter [device] it's what's called 'fixed pitch'. Maybe a
lot of you don't realize this, but if you have a fixed-pitch typewriter
have you ever noticed that the problem is that the letter 'i' [for example]
looks very lonely because there has to be a lot of space on either side of it
The fixed pitch of these characters is 602
one thousandth of an inch [Correction: thousandths of an em] - OK for ordinary alphabets.
But when you get extended characters like a [lower case] Greek alpha,
which has got a floppy head and a floppy tail
they don't look very good at fixed pitch. [Ideally] you have to redesign them but they look
all constrained and not their usual florid self.
There have been no *fixed pitch* redrawings as far as we can find
[for creating] a typewriter-compatible font of the Greek Symbol golf-ball [say].
It's a minority interest. So I've had to do my best in
rescuing Dennis's thesis; work is ongoing it'll take quite some time yet,
to say: "Well we'll have to use a variable pitched typewriter-like
font for the exotic symbols." So, for example,
the [lower case] alpha symbol in Greek requires a variable pitch of 890
thousdandths [of an em] not 602. And if you start to say: "Come on Brailsford stop
being lazy! Just take the variable pitched font
and using your innate [type-design] skills squash it down into being a fixed
pitch version [602/1000] of it. It's hard! If you don't believe me read
my semi-rant back in the Vacation Memo paper it took me something like
120 - 150 hours to create a font called PrintOut and
the results look rubbish unless you have artistic
[type design] innate capability. Which i don't" It means that my lines on the [DMR thesis] rebuild
are sometimes a bit longer than Dennis's because i'm having to use
quite a few variable-pitch characters that are inevitably - they look more elegant -
but they're longer [i.e. wider] than they would be in
a fixed-pitch version. So under my left finger [points at original thesis page] is the
stuff that Dennis left - his display equations.
Swapping over quickly here [and] using the bit stream Pica 10 font
is my attempted rebuild of the same material. I'm still working on it but can
you see the 'pi' symbol there - it looks better
There's all sorts of things. For those of you saying: "Well how are you producing it?"
I've allowed myself the anachronism of going five years
later in Bell Labs history. Anybody who's into ancient UNIX would
say that [this material] was yelling out for 'eqn' and 'troff'
so why didn't Dennis use them? They hadn't [yet] been invented !
His thesis was in [late] 1967. Eqn and troff weren't there until 1972
And [this material] it's got superscript and superscript positions.
And you must respect those because those affect the meaning
of the equations. He was five years ahead of his time and Lord
knows how he did it but in following him - may we be forgiven - we're giving
ourselves five years benefit and comforting ourselves that
had Dennis done his thesis five years later, he
would [almost certainly] have used these tools. So we have used 'eqn' to set these
equations feeding into the device independent
[ditroff] version of 'troff' because stylistically and date-wise
they are earlier than things like TEX and LATEX, by quite a bit.
So, this seemed to us to be the best
reproduction compromise.