FYI, I believe SDF has some version (not the one released recently) of Altair BASIC assembled and running on an emulated PDP-10 available online.
Michael Steil’s blog entry is worth reading if you are interested in Gates and Allen’s MACRO-10 assembler-based development environment (*). Microsoft used G&A’s development techniques to write all their late 1970s BASICs. According to the blog, for the 6502 ports, they built an emulator that leveraged the PDP-10’s ability to seamlessly trap to an illegal instruction handler and then continue on its merry way. When G&A’s unreleased macro package was configured for emulator mode, each target machine byte was assembled as a 36-bit instruction word (**). I’m guessing they did something similar for the 8080, because in their memoirs, the duo admits that they did not own an Altair 8800, nor had they ever run their code on one prior to the famous Albuquerque demo. What chutzpah; I love it!
(*) From my subsequent, more careful read, Steil is clearly a bona fide “digital archeologist.”
(**) This might explain why the 50th anniversary listing looks so different from a typical, native 8-bit assembler listing. For starters, everything is in octal (DEC sorta “didn’t believe in hex," even for the 16-bit PDP-11) plus everything is 36-bits wide.
This just got me thinking, coalescing my various posts above: for the TI “grain-of-sand” microprocessor, we could install an 8080 emulator in firmware, and use it to run the original Altair 4k BASIC code verbatim. The emulator’s job would include suitably fooling the 8080 code into thinking the address space is what it was on the original target.
Because they don’t want to actually make it easy on people nor do they care about accessibility.
I am a touch too young for this era but I do remember passing floppies around to copy.
Naturally they’d go out of their way to make the ‘free’ thing a hassle for anyone to actually use. God Forbid anyone want to run altair basic in 2025. What do they think people want it for, to just STARE at it?
Words fail me.
The one that jumps out ot me is making windows explicitely unable to load on dos compatible alternitives in spite of there being no coding reason it couldn’t do so.
That is truly facinating. I had always been under the idea that the relevant parts of ROM were loaded the ndiscarded rather tha nthe whole thing shoved into ram.
I have a more generous take on the PDF lacking machine-readable text. It goes like this… Bill is going through his collection of ancient relics while thinking about the 50th anniversary. “Oh, look! Here’s is that old printout of Altair BASIC. I’ll send it to a service bureau, get it scanned, and we’ll publish it on my web site. Easy peasy.” Microsoft has already released the source code for at least two of their later BASIC implementations, the 6502 version included in the blog I linked to above, and if memory serves, the even later GW BASIC, both in their full textual glory (Google can take you to it; I think I found it on GitHub). And actually, publishing the listing is in some ways more interesting than the text. This listing is a physical, historic artifact, and we get to see what the line-printer output looked like on the original fan-fold paper. Please forgive me for making light… Here’s a silly analogy: “Darned those rare book librarians! Why did they only publish scans of their Gutenberg Bible? I really wanted an OCR version.” Speaking for myself, I get more excited about the scans, even though my ability to comfortably read UPPER CASE TEXT went away many years ago. I look forward to a decent OCR, at least of the comments. Remember, to assemble the code, you’ll need to a) track down MACRO-10 and a PDP-10 emulator and OS, and b) you will need to recreate the macro package they used but never released. You are better off starting with a good, annotated disassembly, like Reuben Harris and other collaborators accomplished. What the extensive, original comments in the newly published listing can help with is an even better annotated disassembly.
While incompetence is always high on the possibles list. I tend to take a dim view when it comes to microsoft given all the shennanagins they pulled over the years.
I’d love to answer your recent reply, but as Ed kindly implored us to do, after my own guilty-as-charged transgressions on this thread, I’m happy to preserve the Retro Computing Forum as a place devoted solely to (mostly) technical, retro computing topics. It is ever-so-easy to digress into justified criticism. I confess that I have at least 2-3 opinions of Microsoft that don’t agree with each other, even though they live in the same head. If you want to discuss this further, I’d be happy to. Look up my email address on 4004.com, and we can have a friendly but critical discussion that doesn’t have to adhere to Ed’s wise guidelines for this forum.
1 Like
The listing looks to me like it may very well be the output from MACRO-10. That’s consistent with how it says “MACRO 47(113)”.
I’m guessing SDF has a copy of the macros for running the 8080 code on the PDP-10 as you describe.
@larsbrinkhoff, Would you mind expanding the acronym SDF or pointing to their web site? Thanks!
I’ve really enjoyed finally discovering such wide interest in the early Micro-soft BASICs. Initially I was relying on Google, which has trouble with ambiguous acronyms and common dictionary words like “basic” and “logo,” (the name of that other language, which I’ve also had a keen interest in).
Too bad I missed the $5 paper tape sale while I was at VCF East last weekend. It would have been a fun keepsake.
I think it’s Super Dimension Fortress (see FAQ), but it’s at sdf.org and offers various unix related services:
SDF Public Access UNIX System - Free Shell Account and Shell Access
and also hosts the Interim Computer Museum:
wiki - vintage_systems
I have a small basic website live.
If you would like to try it DM me a note with your email address and I’ll send you over a username/password and a link to the site.
All the OCR’d pages will appear on github here.
You can now build your own computer, where the processor is actually constructed from simple TTL circuits. The computer will run the Altair Basic as discussed here (and can do a lot more) ! This kit will cost you only slightly more than 100 Euro. See it here:
In this article I also discuss why the Altair Basic will run on a 8080 but not on a Z80.
1 Like
reads blog.
What is interesting that you had real phone number for back then help, with live people,
not some automated machine.
Now they are so rich they can’t even answer the phone.
1 Like