The PDP-11 Basic Analysis Project | Hacker News Reader

The PDP-11 Basic Analysis Project

learningpdp11.com

72 pointselvis7017 comments

Moderators, consider capitalizing BASIC in the title for this article- it would make it more clear that it is referencing the language, whose name is an acronym.

It wouldn't just make it "more clear" - it would also make the name correct.

And the meaning much clearer as I thought we are learning about the basic of Pdp 11 which I would be interested as this is my first multi user computer and use a lot in U. But basic. Well it is also my 2nd basic other than Apple basic. Still, but not interested in basic very much.

"PDP" being an initialism of "Programmed Data Processor" should also be capitalized along with the acronym BASIC...

This is great! The PDP-11 instruction set is really nice, especially for its time. Lots of addressing modes make to easy to work with data in memory, especially compared to the microprocessor instruction sets that came out later in the 1970s.

RSTS/E an entire PDP-11 operating system written in BASICPlus

> Not sure why this is on HackerNews.

Well, I think it's awesome but the modern world should look away, those wanting to break from current conventions would want to use Xojo here in 2021.

As far as Hackernews...skimming through the site (found this PDP11 post near the end of page 2 on a Sunday evening with 15 comments) and was lamenting at all of the nearly irrelevant political/social crud (like almost 400 comments about Apple using edge-AI to scan photos on your device instead of on their servers after you already allowed them to use their servers if they wanted to). Nothing (or not much that I've found yet) about what we need to be doing to respond to the multi-YEAR chip shortage (besides scream "omg we're all going to die"), such as what it will do to the price of AWS/Azure workloads (perhaps mitigated by shifting our AI photo analysis to the edge without telling people the real reason why? LOL), quick migration to still available chips like ESP S2 from the way cooler microcontrollers, particularly issues with bread n buttah 40nm components on 200mm wafers (for da COBOL, JavaScript and Python billionaires: those are older chips and they make up most of the market)..and what all this means for the industry's traditional 4 year cycle. I think people using PDP-11 components will be safe, as long as they keep up the never ending battle against static electricity and solar flares :)

Not sure why this is on HackerNews. PDP-11 Assembly was my first Assembly Language, taking a Harvard Summer School class it in when a high school student, maybe '82? If I'm remembering correctly PDP-11's instructions are augmented with an Assembly Macro System, Macro-11, providing an ability to create high level language structures and facilities. One of my big surprises in that class was the last two homework assignments: one took several previous assignments and combined them with the content of the new assignment, and we had a mini VI editor! The last one was similar, combining previous assignments, but this one used every assignment in the course, and when combined we had a C compiler. Blew my mind.

> Not sure why this is on HackerNews.

This is the type of content I come to HN for. Nice tight code on well designed hardware, what's not to like?

Somewhere I still have source for a PDP-11 bootloader I wrote back in the very early '80s. Managed to boot 2 or 3 different types of floppy and a HDD in a 256-word ROM, complete with command line interface. I vague recall a trick where I happened to have 102 in a register (from loading the bus event interrupt vector) and a free shift gave me 204 which was a sector read command for the FDC - that got me a crucial extra word saving I needed, to shrink it from 257 words to 256.

It just seems out of place; not like this is some old game console or hardware typically fondly remembered by the HN audience. That what I meant, all you down voting whippersnappers.

You would be surprised, I'm 37 and yet building a PDP-8 on a (large) CPLD, because I'm fascinated with this machine. I even considered building a DTL replica of the straight 8 with PCBs and SMDs for a while, I have some R-series logic gates simulated in LTspice but this proved unpractical to build physically.

I also have both a PiDP-11 with V6 UNIX and an IBM XT replica running ELKS, and I'm currently modeling the EDSAC (1949) in HDL. I find those machines fascinating, and the assembly code that came with them just as fascinating in resource efficiency.

You're my hero, but I hope this evolves into your own SOC design that features a 32-bit variant (no overlays!) with 45 I/O pins, WiFi, BLE and NFC. :)

I expect there’s a fair few HNs readers with fond memories of using DEC equipment in their very early careers.

Me for sure. My first real job was on a VAXCluster. IIRC there was a PDP-11 sitting in the corner of (the very large) room also.

I even have a nice anecdote from that era:

http://www.mattowen.co.uk/blog/dont-screw-up-a-vaxcluster-ta...

And there's those of us for whom these machines are well past our time... but we still enjoy reading about them and having appreciation.

Frankly it's bizarre to me to think this isn't HN-relevant.

"Not sure why this is on HackerNews."

From the FAQ:

Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.

I’m happy to say not all HN readers think “classic hardware” means a Nintendo GameCube. :) There’s quite a lot of interest in computing history around here (as it should be).

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