#digitalhistory

🎄💾🗓️ Day 11: Retrocomputing Advent Calendar - The SEL 840A🎄💾🗓️

Systems Engineering Laboratories (SEL) introduced the SEL 840A in 1965. This is a deep cut folks, buckle in. It was designed as a high-performance, 24-bit general-purpose digital computer, particularly well-suited for scientific and industrial real-time applications.

Notable for using silicon monolithic integrated circuits and a modular architecture. Supported advanced computation with features like concurrent floating-point arithmetic via an optional Extended Arithmetic Unit (EAU), which allowed independent arithmetic processing in single or double precision. With a core memory cycle time of 1.75 microseconds and a capacity of up to 32,768 directly addressable words, the SEL 840A had impressive computational speed and versatility for its time.

Its instruction set covered arithmetic operations, branching, and program control. The computer had fairly robust I/O capabilities, supporting up to 128 input/output units and optional block transfer control for high-speed data movement. SEL 840A had real-time applications, such as data acquisition, industrial automation, and control systems, with features like multi-level priority interrupts and a real-time clock with millisecond resolution.

Software support included a FORTRAN IV compiler, mnemonic assembler, and a library of scientific subroutines, making it accessible for scientific and engineering use. The operator’s console provided immediate access to registers, control functions, and user interaction! Designed to be maintained, its modular design had serviceability you do often not see today, with swing-out circuit pages and accessible test points.

And here's a personal… personal computer history from Adafruit team member, Dan…

== The first computer I used was an SEL-840A, PDF:

I learned Fortran on it in eight grade, in 1970. It was at Oak Ridge National Laboratory, where my parents worked, and was used to take data from cyclotron experiments and perform calculations. I later patched the Fortran compiler on it to take single-quoted strings, like 'HELLO', in Fortran FORMAT statements, instead of having to use Hollerith counts, like 5HHELLO.

In 1971-1972, in high school, I used a PDP-10 (model KA10) timesharing system, run by BOCES LIRICS on Long Island, NY, while we were there for one year on an exchange.

This is the front panel of the actual computer I used. I worked at the computer center in the summer. I know the fellow in the picture: he was an older high school student at the time.

The first "personal" computers I used were Xerox Alto, Xerox Dorado, Xerox Dandelion (Xerox Star 8010), Apple Lisa, and Apple Mac, and an original IBM PC. Later I used DEC VAXstations.

Yes, I really am just coming out swinging at all of my own interests and potential career opportunities. These thoughts are all interrelated ideas that have been floating around recently during a few of my classes.

Recently, a professor poised the question, “are we [historians] good at our jobs?” Which then sent me into a long, impassioned speech about how the role of a historian is inherently flawed and the work will always be done badly, but we do the best we can with the knowledge and backgrounds that we have. Even a week later, with further ruminating on the question and my answer, I have not changed my mind. 

(I thought this photo of our visiting anthropologist at Vindolanda looking very done with me as I asked a question was fitting for this post)

The role of historians is to encourage constructive thought and a better understanding of one another through the studying and writing of history. Seems simple enough, but then you have to consider that when we study a person, event, time period, etc., there is always something missing, be it an event that was unrecorded, an artifact that was destroyed, or an account that was misconstrued previously. Then with writing, it is impossible to include every perspective (even if we had them) while also making it accessible to every level of interested parties and coherent as a written work in its own right. Going even further, the role of a Public Historian (to interact with the public and help in education and advancement of historical understanding) is a job that is already complicated by the aforementioned problems in studying and writing. 

Historians are bad at our jobs. Because we don’t have the tools to be good at our jobs. Those tools just don’t exist. But we do the best we can with what we have, and we are better than we were before. In the future, those historians will hopefully be better than us, but still bad, because it is a flaw inherent to our discipline.

But this failure can also be humbling, because if we recognize that we are always going to be doing an imperfect job, then we are motivated to try to do as perfect of an imperfect job as we can. Then future historians will have a stronger base to work from. I know especially as a grad student that a lot of us get hung up on the idea that any research we do has to be original, but nothing in research is completely original. We are always standing on the shoulders of our predecessors, as shaky as they may be. 

With a shaky foundation though, the metaphor continues that eventually the discipline will collapse in on itself. So why hasn’t it yet? My thoughts on why it hasn’t extend into why I think conservation is often a fruitless enterprise. One of the only guarantees that we have in life is that we will die. That knowledge, whether we can pinpoint it or not, is what motivates us to do anything with our time, because we know that time is finite. That impermanence applies to the material objects that we create too. Humans spend millions of dollars a year on embalming dead bodies in vain attempts to prevent the inevitable and ignore the reality that we will decay. Museums and archives do the same thing. We want to matter on a grand scale. Archaeology does the same thing, but in a destructive way. We go to great lengths to make our past matter, so that we matter in the present and will matter in the future. Even if we recognize that eventually everything will no longer matter, we prop up the institutions that allow for us to feel like we matter in the now, and fulfill our belief that we will matter in the future.

That got a little bit nihilistic. 

I am a Historian. I am a Public Historian. I am an Archaeologist. I participate in all the things that I just spent 500+ words saying are bad. Because wanting to matter is what it means to be human. And in my opinion, wanting to let other people know that they matter is what it means to be a Public Historian. There is a difference between telling someone that they matter and working with someone to prove that you believe that they matter, and that difference is what I like to explore. 

Activity 1

Website Design / Digitization, OCR, and Text as Data

I worked with two very distinct kinds of digital sources for the first exercise. I never looked at these kinds of sources deeply until now, or moreso, I knew within me the differences, but comparing them was something I would not have done on my own. As someone born in the growing digital age, I'm used to having these sources accessible to me.

Despite both being accessible online, they perform different functions, are created, preserved, and experienced in their own ways.

Digital history is mediated, and I am made more aware of this fact, as I explore the two sources. I find that they are both authoritative in functions. They are both searchable, organized, and widely accessible. But because both sources are shaped by the technological assumptions, they answer to decisions made by institutions: the newspaper editors, by the library of congress. It proposes a limit in preservation and choice of what data is accessible for us to view

The first link is a digitalized newspaper from the Library of Congress.

The second, a born-digital website archived by the Wayback Machine.

Both can be freely accessed online.

THE DAILY WORKER (September 1, 1927).

This digital source can be accessed through the Library of Congress's Chronicling America collection. The name itself is interesting. It is to chronicle what was. This specific daily newspaper is political in nature. In a closer read, it focuses on labor movements during that time, depicting the "left" side of politics critiquing capitalism. Even the ads and editorials reflect this ideology.

I find the detailed metadata of Chronicling America to be its strength. I was able to search by date, state, publication, and subject or keyword, making it easy to navigate and locate what I might need.

I was thinking of two things as I explore the site: what is the scope of the archived newspapers in the database? I encoutered only two results with my selected search. Similar to a physical archive, I wonder who made the decision to digitalize these primary sources.

I did a bit of external research about The Daily Worker, and come to find its roots aligning in Communist Party ideology. This version has shaped institutions like the University of Illinois at Urbana-Champaign Library and the Library of Congress. The decision to release these specific newspapers must be catered to diffirent individuals or is it to inform us as well?

In my experience with digitalized newspapers, some can be hard to read due to the scanning quality, or OCR proccessing. But the metadata organization of the site is extremly well done in my opinion. I could read each word, zoom in or out and easily access the provided images.

If this site were to disappear, the contextual information provided will be lost along with it. I must have been ignorant until this point because I never knew this to be the case in the Americas back then. But now I am a little bit informed.

Tumblr, 2007-2013, Internet Archives Wayback Machine

I decided to pick this site because a few days ago I accidentally deleted my Tumblr account containing blog posts from when I was 18 or maybe even younger. I was going through reddit and got informed that this cannot be undone. That account of mine is lost forever from their database. A reddit user recommended the Wayback Machine to recover older posts, but I am unlucky and could not find anything regarding my account. It made me a bit sad because they contained my memories and my younger self blogging and recording.

The born-digital source of Tumblr was created when I was just 6 years old. Since then, it has transformed into a web of sophisticated digital platform capable of using bots. I used the Wayback Machine to explore the archived versions of Tumblr from 2007, 2008, and 2013, 2014, and adding my experience, till now, 2026.

The left side images are from its founding years, and the right ones are from mid-years. This showcases the rapid growth of digital platforms. They evolve based on feedback and user needs. The early version is text-based and minimal, containing what essential tools you need for a blog site.

In just 2008, it becomes sligthly more refined, but simpler compared to 2013-2014. Now, tumblr is one of my favourite blog sites. It is capable to adding embeded links or even inter-linking other sites.

As you know, this blog is done on Tumblr.. :)

The Wayback Machine can only capture a fragment of what the experience might have been with Tumblr, for many individuals. Tumblr has become so much more interactive, with newer design elements, such as replies, reposts, notes. The Wayback seems to have archived up to the year 2016. This explains why I could not find my lost account in the archive. This limited scope of archival data makes me wonder if they would require informed consent to add more about the remaining years. I personally do not remember signing anything about this. Nevertheless, I am indifferent about this decision to share my personal data.

I discovered the structures that shape how I use Tumblr today but not the lived experience it had, though one can simply imagine. The access to the archive, captured only what the Wayback Machine could provide me. It has succesfully captured the preservation of Tumblr's fragments but not its full ecosystem.

Because it is a born-digital archive, Tumblr's content is often personal, or user-generated. This can cause an ethical problem about who's data is preserved and if there are policies or consent involved before it is shared with the internet. Maybe I will check again in tha few years, if they decide to showcase or capture my old blog site on the Wayback Machine.

Activity 2

Reading Like a Machine: OCR in Action

While doing the OCR activity, it emphasized how technology shapes historical interpretation.

When I scanned the left photo, an excerpt of Georgias, it assumed a very clean printed text, since all the lettering and text are the same font and layout. The main text was decoded very easily and when copy-and-pasting, most text is searchable. The smaller fonts in the side margin were not easily captured.

On the other hand, when I scaned my notes from a class, it failed to recognize any of my handwritten notes. The text can be selected but it is not searchable. It produced an unreable text. If I simply look at it, it is legible but the OCR failed entirely.

For many historians, this error matters. If I were to research a source that is handwritten, the OCR may fail to recognize it and it becomes invisible. Valuable information is lost: ideas, names and content. This doesn't mean they did not exist in the past but they are misinterpreted.

For centuries, archaeology has depended on shovels, chisels, brushes, and the patience of humans carefully dusting off ancient stones. Our understanding of lost civilizations—like the Indus Valley, the Maya, Mesopotamia, Göbekli Tepe—has been shaped by decades of slow excavation, painstaking cataloging, and endless interpretation.

I just updated my 200 Years of Digital Milestones list - from Memex to Python.

The additions I made and why they each matter:

1) Memex (1945): As a pre-digital concept, Vannevar Bush’s "As We May Think" paper introduced the Memex - a machine for storing and linking information. It is often cited as the (conceptual) ancestor of the hypertext link and the modern web.

2) Altair 8800 Context (1975): Did you know that Microsoft's very first product was Altair BASIC? The Altair was a pivotal moment....marking the true beginning of the personal computer industry.

3) DNS (1983): I added more detail, including the foundational RFCs 882 and 920. These standards established the distributed architecture that allows the entire internet to function and scale globally.

4) cURL (1996): This seemingly simple command-line tool is the "engine" behind countless scripts and applications, enabling nearly every piece of software to transfer data and talk to APIs over the internet.

5) Python (1991): Starting out out as a hobby over the Christmas season, it has become a global favorite fundamentally changing how developers build everything from data science models to massive web applications.

Understanding such milestones gives us a clearer picture of the technological and conceptual bedrock of the digital age.

Check out the updated list https://veritythink.com/200-years-of-technology-milestones/

The cover image was generated with Google Gemini. Interesting to see how AI connected things!

#interestingfacts 93