Hi everyone, so next talk, we have a geometries spin-ellist here who will speak to us about
how they found the V4 tape and upload the data to the UNIX history repo.
Hello, good morning. As you know, UNIX has defined the way modern computing works.
It was developed in the World Famous AT&T Bell Laboratories that is a place associated with
no less than eight Nobel Prizes and three touring awards. And yet it started the life out of
a failure. AT&T, General Electrics and MIT will be building a system called Maltics in the 1960s
that was a bit too ambitious for the capabilities of the time. So AT&T pulled out of the project,
it wasn't going to well. And can Thompson, other scientists found themselves without a subject of
studies. So can Thompson later joined by Doug McKillroy, Jefferson and Dennis Richie went on
and developed the first non-named system on a PDP 7. That's some very interesting ideas in it.
And based on the success of that system, they created the funding proposal to Bell Laboratories,
they needed to do that even in that well-funded place for a more powerful computer. Initially they
asked for a PDP 10, which cost about half a million dollars at a time. Bell Ups told that they cost,
and at the end they got the PDP 11, which cost a tenth of that price. And maybe the lesser
capabilities of that system influenced the direction of Unix. Over the 1970s, a large group of
people, you see them here at the later age, they were very young and powerful. At the time,
they developed on and created a series of Unix editions. These were numbered following the
editions of the manual that came out each time. In various states, you see here the seventh
so-called Bell Ups research edition from the first one to the seventh one. So source code was
not versioned even at the last edition there was no version control system, but the manuals were
versioned through their printing and adding an edition word, word on it. Not a lot has survived
from the first edition, so for the first unnamed one, it has survived in printed form and people
have also already already made it run. In others, when you see you have some parts of commands,
some parts of the kernel. At the fourth edition, we had just the documentation.
Which brings me to 1974, and this letter from Kent Thompson to Martin Newell at the University
of Utah, which says that we are delaying the delivery because we are on a lot of copies
of the documentation, but there will soon send you a system. Newell, you might know him,
he is the person every one computer scientist, specializing computer graphics. He is the creator of
the famous Utah team or the benchmark used for 3D rendering. So it seems at some point there was a
version that could be shipped from Bell Labs to Utah, and something like this status of
the American, it's not the original tape, but I want to show you to you for those who are not familiar
with the computer tapes, got shipped from Bell Labs to Utah. Fast forward to 1828 of July in 2025,
and the storage closet of Robert Rich's flat research group at the Maryland Engineering building
you will see here, where Alex and American researchers associate in the group found the tape
among the documents of Jayle Pro. The findings was widely reported, even on broadcast TV.
To, so was there anything on the tape? It was important to read it, but also it was one tape
we never had access to it before, so it was considered very valuable. So to avoid high altitude
cosmic radiation on flights and airport scanner damage, lab members jodering, you see at the
center in Thalia Archibald, you see on the left and there took 11 hours drive to the computer
history museum in California. There it was read by Archivist Alcosso of bit savers, famous archiving
site, you see him here at work. To minimize tape where he used the system developed by computer
historian Len Shashik, so he first read the tape not as a digital bit, but as a 1.6 gigabyte
of analog data using a multi-track analog to digital converter. This means that a lot of hardware
that you see here on the left that happens inside that is implemented normally inside tape readers
can be implemented in software and thereby the tape can be virtually read again and again with various
settings so that can be restored. You see here the waveforms from various tape tracks and
here zoomed in to see how they can be seen and various elements how they can be adjusted.
This was successful and now if you go to archive.org using Shostek's read tape program,
this 1.6 gigabyte analog data were converted on 2.5 megabytes of digital
the format which is compatible with a image emulator and both are now available on archive.org.
Think of it, tape is 2.5 megabytes about the same as a single picture we take with our mobile phones.
What's the legal status of this tape thankfully in 2002 called data which on the IP rights
to Unix at the time wrote this letter which if you squint well enough looks like an open source
license. So effectively it can be uploaded on negative and shared and built upon and run and so on.
And then people started using it for example Brian Rodriguez developed this erotic
ebook the Unix 4th edition source code commentary where he analyzes the entire kernel and how
it is built, how you can run it on an emulator following a very influential book from the 1976
by John Limes from the University of New South Wales which taught many generations of computer
science students the design of a real operating system kernel. Also Angela Papenhoff who
gave a very interesting talk at 39c3 if you weeks ago made it run on a pdp 11 and you later
and also published a tar file with the tapes contents. I employed the file to add the tapes
contents to the Unix history repository. What is that? It's a repository on GitHub on the URL
you see there that contains a history of Unix from its inception so the first unnamed version
until today for a lot part of it it traces the 730 search editions work that happened at the
Berkeley the BSD editions 36 BSD and ends up with the 3 BSD modern editions from the very complex
and long history of Unix it traces one line they want you see here on the in orange. It contains
snapshots of the research editions and values Berkeley editions then commits moved from
CCS this was the source code control system used for many years at the Berkeley and then finally
normal free BSD commits as they move from CGS to subversion and now git. The way it is constructed
allows us to run git blame on it here I do it on times on dot c and amazingly we see on the
modern free BSD times on dot c lines that were apparently written by Dennis H.1979 actually some
of you may realize that those lines shouldn't be there because what was released by Berkeley
was supposed to be a complete clean source open source implementation of Unix so it's a mystery to
me to to add the contents of the tape to the repository what I do is I what I did was first
of all associate files with actual authors based in documentation and the information that was available
at the time even oral histories and things that people who were there told me now and I got
the timestamps from the actual timestamps of the tape and this each timestamp is a separate
commit. Let me demo you how the system works you can go to a Unix before dot dev and see
the running this not work at it but I find it pretty cute cool and it shows a Unix system that's
and what we expect so if I type on the command line I can change the directory to TMP
I run the line editor it's what happens when you press on VIM a Q I append lines and I write
the small main function with a hello world that you would expect.
I press dot 2 finish my input I write the file to hello dot c and then I can compile it
if I list the files in the directory c and a dot dot and if I run it press to get hello world
from code that was written at that time. So this is really important because now we have a complete
it's the first complete Unix distribution we have the kernel the commands we already had the
mantpages and the c compiler. This version produced many interesting things structured programming
so kernel was implemented in a language called the new B at the time you can guess which language
this was 7800 lines of new B and just 1000 lines of VDP 11 assembly. Provided I think for the
first time a language independent API so you see here the pipe system called documented both in the
way you call it from assembly language R0 and R1 RDP 11 registers and from c to get an array
of two file descriptors. It used the data structure definition and reused through header files
it provided the device driver abstraction through special files many of the files are
completely nonsensical today speech synthesizer and the spider interface but the driver interface
the way this abstraction was implemented is still available today and previous editions but also
similar design on Unix and even on Windows if you try to write a Windows device driver.
Also it had a properly typeset manual you see the fourth the third edition is typewriter
the other one is a typeset. It had a snowball and implementation a dynamically type string and
pattern processing language that has influenced the or compared and thereby Python 1600 lines of
C and tried to find out what the way it was written it was just a quick entertainment for
again and the application that survived was a program that solves the instant insanity page and
here you see it written in snowball. What are the tapes contents regarding dates what I did that
created the rank of diagrams about from the files of all editions that have survived and if you
and as you can see the fourth edition the files match many of them match the manual page some
are associated with the later date but they seem to be relatively close to the manual date.
I also wrote a script using a git to git blame to see what code was inherited from previous
editions and as you can see the fourth edition in had some parts of the third edition and also
the fifth edition inherited a large part of the fourth edition. I also looked at the evolution of language
used because it was a time C was being used more and more and you can indeed see here that the
fourth edition content is a significant part of C code something that continues and gets expanded
until the end of the decade and I think we can unfortunately be fortunate to say that it
survives until today. Thank you very much.
So we have a couple of minutes for some questions. Thank you very much. I volunteer for
computing history group in Newcastle UK and about 10 years ago the retiring head of school
handed me a tape and he said this has got unix on it I think. I wouldn't get too excited because
I'm fairly sure it's it's well known it's V7 or something and obviously the next thing I need to
do is go back to him and ask him because he's still that I can still kind of contact him but
assuming there is something of historical interest on it what would you advise our next step to be?
Contact the computer history museum to get further advice we may be witnessing history here.
Thank you. Thank you very much for bringing this up.
Riddle or tape is tricky they can get destroyed so please don't touch it. For example the tape
right if you doesn't have any plastic parts, cups, tants and so on in order to minimize
it weren't there. When converting the binary data when converting the
data to binary how did you make sure that there were no errors in the transformation?
So when I didn't convert the tape I just uploaded it on GitHub but when the binary data were
converted how to ensure there were no errors there as understand the CRC checks in the tape
reading mechanism and then people actually looked at the tape contents to see that it was okay so
2.5 megabytes is fine and indeed we found some people find some blocks that were mislade
and manually patched them to collect everything. Amazing, cool.
We are on time but let's take one more question and then we move to the next talk.
Hi, thank you for the amazing research. The Bose Extenders came out in 1998. I was wondering
to what extent does this very early incarnation comply to the later Bose Extenders? What is
to what extent does this feel like a real modern units? To what extent does it feel like a
real modern units? There are differences, for example I typed CHD, rather than CD. Many of the tools
are already there, command options are missing and some tools are not there yet.
And the kernel like the system pulls that were later the fines and the Bose Extenders,
they're still being developed at this point again. Thank you for that. So what happened with
the interface and the system calls? There is this paper you can find that documents and
the repository on GitHub that has a time line of all unique facilities, command system calls,
when each one appeared and when some of them also move the way. And there you can find the exact
timeline and see what was there and how it compares to the 7th edition and later ones.
Very impressive. I'm going to look at that up. Thank you. Thank you.
Thank you again.