The Great 202 Jailbreak - Computerphile

the idea was this was going to be the Bell Labs memo that never was it would never be released so said the lawyers because it was too sensitive for 33 years this was all that we had and I suppose in modern parlance it became a sort of reverse engineering jailbreak as you might say many of you know far better than I do already about the two big heroes of Dennis Ritchie and Ken Thompson there's a third person we're going to bring in today and the one if you like it Bell Labs that I know really really well for more than 30 years now that of course is Brian Kernighan and I think if only from this book here those who haven't heard of him they suddenly say oh yes probably the third best known person in the UNIX finland's after Denison ken one of the suspects you recognized straight away as me the one at the far right is my colleague Steve who features later on in this story and the person in the middle there the bearded gentleman is Brian Brian Kernighan that's taken about three years ago when we visited Brian and it's in a coffee shop just off the main campus of Princeton University when you look to the version 7 UNIX manual the thing that really struck you was it at Bell Labs they not only could afford pdp-11 'zv axes and all sorts of stuff but they could afford typesetters it's hard to realize nowadays what that meant laser printers had not been invented at best if you were lucky you could get a good if you like dot matrix printer effect but actually getting x roman curia Zapf Chancery Helvetica Arial whatever turns you on no that was not in the compass of normal mortals because it cost a heck of a lot of money so what we're going to take a look at today is how and why Bell Labs had typesetters what they did with them and how they really were instrumental in making typesetting democratic for the rest of it was very early work but it was massively influential and one of the people who led the charge on that because he did a lot of the work himself and he was kind of informally the leader of the typesetting software effort at Bell Labs was Brian Brian Kernighan Bell Labs choice of third-generation typesetter would only cost fifty thousand dollars in 1979 money which is just horrendous to think of by comparison you could easily buy a house you could easily buy a house for $50,000 a really very good one I would think yeah they look long and hard what was available and decided that they would go with Mergen tyler and at this machine UK design is called the liner tronic 202 this was the one step before laser printers came on the scene naked mini - floppy disk drives control console paper tape here is a board from the naked mini and it shows you very definitely how solidly mini computer the computational facilities were and there's all of the boards that comprise the naked mini receptor cassette fed from bromide paper at the back hidden under their high-res cathode ray tube 972 dots to the H and shaped a bit like a letterbox in many ways you exposed the bromide paper in bands and when you finish doing the current band you mechanically move the bromide away from it at huge cost from either liner type or some other supplier you bought a bromide or film processor you took along your cassette you fed it in to the end of this thing which have three separate tanks smelly developer with whether yes I can smell it even now wash water in the middle after the developing was done of the image and then of course fixer at the end and the fixer smoke the worst of all czar sort of faintly acidic smell about it then it came out at the end it probably had another one at the end and then it went through a dryer or your hyung is up to dry and then finally you've got your beautiful bromide output which you could slice up and make it into page sized slices what you then did with it was if you just wanted to send a proof of what it types it out all your friends there were of course Xerox and other photocopies around you could photocopy the bromide output but if you wanted really high quality and you were doing a long print run what you would have to do at this generation was to send your photographic output off to a plate maker that would convert your photograph into an offset printer metal plate the idea is you have a plate on a cylindrical drum which rolls round and round at very high speed and can print off tens of thousands of copies of things like newspapers or whatever so that's basically the technology behind third-generation cathode ray tube driven typesetters and as far as Bell Labs are concerned it just changed everything because with the ability to be imaging onto a cathode ray tube you could not just have the ability to use preset fonts like in earlier generations you know letter S is magnified various size you got all of that but you had the ability to draw lines you could do primitive line graphics and certainly Brian and others at Bell Labs really really wanted to do that they could see the potential straightaway but in terms of getting the full value out of this what they naively perhaps thought shouldn't be too much trouble was to ask Mergenthaler very nicely if they would let them have the spec for how the digital fonts were held on floppy disks why send Mergenthaler because we want to create our own lace well I gather the roof Ellen a total total total disbelief why would you want to do that you know this isn't a machine for amateurs one example of the fonts that they wanted was a set of chess pieces this is the time to bring in one of our other heroes Ken Thompson already mentioned in the previous unix video he was part of Brian's team for commissioning the 202 typesetter it was led by Brian himself of course and crucially they also had a hardware man called Joe Condon very talented hardware engineer some of you will know that Joe Kannan and Ken Thompson were famous just before this era mid seventies of creating the Bell chess machine ken was there a sort of ultimate software guru who was mad keen to create his own chess font and also very happy to get deep into the line of Tron as deep was needed Mergenthaler just said I'm sorry gentlemen it's a flat no we are not going to reveal to you how our fonts are done yeah yeah we thoroughly accept your bell labs you know you have enough hassle from antitrust legislation we know you are not going to set yourself up as rivals you're not going to become just a font shop and you know do cheaper fonts now as we do-- we accept it but nevertheless there was a feeling rightly I think in Mergenthaler that this was like opening Pandora's box even though these three talented chaps at Bell Labs were quite prepared to sign every nondisclosure agreement going the answer was firmly no absolutely no so they basically said well we're going to do it anyway and I suppose in modern parlance it became a sort of reverse engineering jailbreak as you might say the with the wisdom former guitar which you'll never do it you know our fonts are not deliberately encrypted but they are so compressed and so compact and in such such an obscure format you will not succeed in deciphering how we do it and why we do it to which I think Brian probably muttered under his breath what you don't know is I've got a secret weapon and it's not a piece of hardware it's called Ken Thompson it took can with some help from Brian who always under plays his own role in this basically between two and three weeks to get the overall idea of how it all worked it took about six weeks for total knowledge but that included complete knowledge of exactly what the resolution was of that CRT the timings everything you just wouldn't wanted a more talented team to prove that this could be done they created their own fonts ken did his chest fun there were no chess fonts were at the time there's hundreds of them now an email he sent to me said well I just want to do something really quickly because I wanted to publish books and I wanted a proper chess font zaps Palatino but there is Ken Thompson's chess font in action the whole of this book all done on the Linotype 202 so that is one of the rationales for wanting to be able to do your own fonts Brian and I have traditionally referred to this work that he did as the vacation project right because it was in the vacation period in the middle of 1979 that they spent their six weeks reverse-engineering the 202 but when it came to the turn of 1980 Brian was absolutely adamant that he wanted to write a memo about not the fine details of Howard's had been done but just the overall picture saying we did it this is what we can now do isn't it wonderful not in any way to be an T Mergenthaler although their version of the 202 was very very unreliable as you'll be able to read in this memo we'll try and set up some web pointers for you as part of this video so you can read it for yourself but he just wanted to tell the story Mergenthaler got wind of it and basically said no absolutely no got in touch with Bell Labs lawyers and to cut a long story short it was suppressed the idea was that this was going to be the Bell Labs memo that never was it would never be released so said the lawyers because it was too sensitive but it was with hindsight a real point to the future when fonts would be commonplace within the laser printer era and so on for 33 years this was all that we had as the hardcopy evidence of the technical memorandum the thing I'm kicking myself for now is that I didn't actually keep any bromide I've got lots of other bits and pieces here I've got font books for the supplied with the Linotype 202 but I didn't actually keep any proper bromide and nor it would seem did Brian because here this isn't the bromide it's an nth-order photocopy of the bromide off the 202 and you can see what's happened every photocopying process adds so many percent the apparent boldness bits have got chopped off and truncated off the bottom filing marks here however as you turn over you can begin to see just what was turning them on about the abilities of the 202 for the first time using Brian's pick preprocessor they could draw a line diagram of how it worked on the 202 little cathode ray tube 16 bit naked mini driving it floppy disk character definitions on integrated line diagram out proof not stuff that you had to have drawn by an artist and pasted in and made a place of or whatever afterwards the governing organization if you like for what's left of Bell Labs is now called alcatel-lucent so I suggested to Brian and a good mutual friend chuck Bigelow typographer said yeah yeah you ought you guys ought to do this I said why don't we ask the powers-that-be for permission is it's not sensitive anymore 33 years after the event please can we recreate the vacation memo as we came to call it the really big plus point of course was that it was typeset in this type SATA version of that original run off program tear off the typesetter version or rough tear off can be equipped with macros to help you do the layout and all this sort of thing anyway to my amazement I've got a more authentic an ancient set of SuperDuper tear-off macros for doing Bell Labs memos than even Brian had so we were able with a fair bit of effort to recreate the memo at the sort of quality but would certainly been obtainable from the 202 if only we'd hung on to the bromides yeah but we didn't however this of course has all been done via PostScript and PDF and modern technologies but we're trying as hard as we possibly can to still retain the look and feel of what it would have looked like at best quality coming off the electronic to route to one of the best ways to show what we were up against and when we succeeded or not was to show an a/b comparison here is the original memo not as a bromide as it should have been but as I sort of n thought a photocopy of it first of all finished off properly at the bottom don't forget we didn't have the appearance of this we didn't save the bromide but what we did have was the tear off source code yeah Brian had saved that thank heavens we would have been struggling without that although in the end we could have rebuilt it with optical character recognition and lap but he saved the tear off so instead of running tear off through a back-end to the - OH - we never-- and tear off to another back-end out to PostScript in PDF so here we go nice and clean knowing bleed straight off a good quality laser printer Oh Bell Labs logo revived as a font character all over again and even shrunk down it says here the most obvious special character we use is the Bell System logo I'm jumping ahead now the thing that Brian was trying to get across in this memo was this in this era you mustn't imagine that the 202 and its characters were able to do splines and arcs and complex curves no they couldn't I mean quite apart for anything else there wasn't the process of power to be able to do the computer graphics necessary to turn those into dots on the CRT fast enough know what you had to do was to simplify and make all your characters be lots and lot small line segments so these diagrams here as you can see I put little arrows on not really part of the character just to emphasize to you this is where each line segment begins and ends so that Helvetica font letter e is a bunch of straight lines and there were severe limits on how many you could have at most of straight lines in any one character but it worked well enough so long as you didn't take your character size above about an inch at most and then you began to be able to see the straight line approximation is the naked mini was going flat out and even then it could just about cope with characters done as lots of straight lines it certainly could not cope with arcs and splines okay so let's just summarize the two big challenges that we faced in recreating this vacation memo fonts like Times Roman Helvetica Korea if there there are no problem they existed on the 202 but they've been brought forward into the PostScript and TrueType modern fonts era those are easy to get hold of the harder bits here was what we had to recreate because they just didn't exist except on the 202 the first time most obvious is Ken's chess phone so starting from first principles again I created a few shapes using Brian's pick program and handed them over to my colleague Steve whose photograph you've already seen Steve Bagley we also discovered by the by in doing this that Ken Thompson faced with the problems of fonts on the 202 where individual character shouldn't get too complex you'll never guess how he did something like a porn here on a shiny black background the overall character would have been too complicated so what he did was he created extra characters which was the cutout shape at the back partly shaded and then dropped the pawn shape on top of them as a zero width character so it's a super position we were authentic we did that in our replica the other thing which caused me many sleepless nights is that the liner Tron font for doing program printouts courier if you like was called printout heaven knows why ladder type Mergenthaler didn't just do courier but they didn't next thing to do is to phone up the font shop in Cheltenham and say print out on the tour - it's been turned into PostScript hasn't it by some money for some reason no comes back a reply it was 202 only we never converted that one so decided to recreate it in conjunction with my friend Chuck Bigelow type designer we had a look at this print out font in the liner type fonts book Chuck took one look at that he said that's come from a variable width typewriter font something like excelsior but they've hacked it about to make it a fixed pitch font like courier and it's quite right if you look at the tiny details you can see it's Excelsior messed about with so with the sinking heart I started off with excelsior I spent I'm not exaggerating 120 hours chopping stems chopping down serifs resizing placing in fixed with carrot positions trying all the current as I could to get them to look right it's not bad I'm still not happy with it at all but if somebody was a revelation to me as to just how incredibly labor-intensive type design is but for the sake of authenticity and when you look inside the vacation memo you will see Brian wrote a heartfelt letter to Mergenthaler about the lack of reliability of their 202 and he wrote it in the print out font so I wanted it to look right so that just about summarizes I think the big two challenges that we had to overcome and I think we're now just about completely succeeded slight restoring pictures you don't want to over restore you want to use exactly the original materials and do it just right but overall I'm pretty happy I don't think we did too badly all of your characters in the current font available as photographic images what you've now got to do is to transfer the photographic image of the capital letter S shall we say from the strip onto a piece of photosensitive paper you put this down into a thing that looks like a top-loading washing machine in the laundry

Channel: Computerphile

Views: 476,724

Rating: 4.9553285 out of 5

Keywords: computers, computerphile, typesetting, mergenthaler, 202, linotronic 202, type, printing, troff, computer science, Professor Brailsford, jailbreak, reverse engineering

Id: CVxeuwlvf8w

Length: 19min 54sec (1194 seconds)

Published: Thu Dec 12 2013

Reddit Comments

[u/Ramin_HAL9001]

The typesetter was programmed with TROFF, and some of the memos written digitally at Bell Labs and typeset for the Linotron 202, survive to this day. Professor Brailsford of the University of Nottingham, in corroboration with Brian Kernighan, have made efforts to build a virtual recreation of the Linotype 202 that outputs to a PostScript file that looks as nearly identical as possible to what the Linotype 202 output would have looked like.

[u/classicsat]

From what I gained from the video, they wanted to embed their own diagramming, plus the Bell logo, into printed manuals, without having to optically add them after the fact.

Their custom chess font was just a bonus.