today at 9:21 PM
I had Claude Opus disassemble the CDC 6600 dead start panel. The hard part was finding a better image of the switches so the vision could read the bits.¹
The content isn't very interesting, and Claude's comments aren't very detailed. Not bad for 2 minutes of work about a 62 year old computer though. Look out Ken Shirriff, AI is coming for you.²
Addr Octal Instruction Meaning
0001 7512 DCN 12 Disconnect channel 12 (put it in a known idle state)
0002 7712 FNC 12, 4000? Send function code to channel 12's device
0003 4000? └ function code (last bit unclear: 4000 or 4001)
0004 7712 FNC 12, 0001 Send another function code
0005 0001 └ function code
0006 7712 FNC 12, 1500? Send a third function code
0007 1500? └ function code (least certain row)
0010 2000 LDC 0160? Load A with a word count
0011 0160? └ the count
0012 7412 ACN 12 Activate channel 12
0013 7112 IAM 12, 0015 Read A words from channel 12 into memory starting at 0015
0014 0015 └ destination address
2. Not really. I have no idea if this disassembly is corrrect.
3. Quora is prison for words.
today at 10:15 PM
today at 8:13 PM
EDSAC as early as 1949 had an "initial orders" module. A boot-up ROM. There was a bank of rotary selector switches, to set the octal digits in each ROM word.
David Wheeler (of subroutine fame) figured out the most sensible thing to put in the tiny ROM was a paper tape loader and mini-assembler that loaded the rest of itself from paper tape. So at switch-on the machine would start reading the tape input and run. Programs could be written on the teletype with mnemonics and relative addresses in octal.
It seems a little strange that more advanced later machines like the original PDP-11 from 1970, couldn't "autostart" from ROM like that. You had to toggle in a bootloader.
I think that was because core memory was non-volatile. (EDSAC didn't use core; it had a refreshing DRAM-like delay line memory.) With core, you only had to toggle the bootloader into once and, provided your software didn't accidentally overwrite it, it was still there after a power cycle. So re-toggling in the boot loader was not really that common, despite how much lore surrounds it.
today at 8:37 PM
DEC supplied optional boot rom cards for UNIBUS, starting with the BM792, which arrived as a 32 x 16 matrix of diodes. You had to remove some of the diodes by hand to set the boot code.
Later cards used PROMs, and were pretty fancy. The M9312 had 512 words and included some basic CPU diagnostics. Different variants handled boot from disk, paper tape, console, etc, and you had to specify the options you wanted when you bought the card.
today at 8:10 PM
I'm pretty sure Kay's not quite correct about the Eniac not being a stored program computer. In it's original form it obviously was not, as it had to physically reconfigured to solve different problems. However, after the war it was rebuilt to operate like any other stored program (von Neumann architecture) computer, as it was the first recipient of the design philosophy seen in the EDVAC report. It operated in that mode from '48 to '55, when it was decommissioned.
ENIAC in Action: Making and Remaking the Modern Computer is an excellent summary of the initial design and redesign of the Eniac.
today at 8:27 PM
Apparently Eckert (John Mauchly and J. Presper Eckert designed the ENIAC) claimed that von Neumann basically stole their idea of the stored program and that they had already came up with the idea and he just took it and ran with it as if it was his
> And John Von Neumann? He came and looked at our stuff and went back to Princeton and wrote a long document about the principles. He gets a lot of credit but the inventions were ours. Someday I’ll write a book on who really invented the computer.
>Johnny learned instantly, of course, as was his nature. But he chose to refer to the modules we had described as “organs” and to substitute hypothetical “neurons” for hypothetical vacuum tubes or other devices which could perform logical functions. It was clear that Johnny was rephrasing our logic, but it was still the SAME logic. Also, he was introducing different but equivalent symbols; nevertheless the devices still did the same things. Johnny did NOT alter the fundamental concepts which we had already formulated for the EDVAC.
>Small wonder, then, that computer history gave von Neumann the credit. Eckert and I, who left the Univ. of Penna. In 1946, no longer had access to the documents which might have helped to show “who did what, when.” But after many years, litigation has unearthed some of those documents, and historians can read what was once classified. But, even after declassification, those reports are not accessible to most people, since they were reproduced in such small quantities. Nevertheless, we hope that more historians will refer to them.
today at 8:48 PM
Eckert and Mauchly weren't reliable narrators of the history of their work, given how much they needed to claim in order to get the patents that were later invalidated. They claimed quite a few things that were later disproven in court or through historical study. At the least, Eniac was designed by the team at the Moore School.
von Neumann's "First Draft of a Report on the EDVAC" was both a summary of discussions by the Eniac team as well as von Neumann's own original work proving and expanding on various aspects of those discussions. It's called the von Neumann architecture because he was the author of the seminal paper, not because he laid any particular claim to the ideas. Eckert and Mauchly were mostly upset about the paper's existence, regardless of author, because it made it impossible for them to patent the stored program idea in general.
today at 9:25 PM
Saying "like any other stored program computer" makes it sound like there were a bunch of them, but as I understand it there was really only ONE up and running at that time in 1948 - IBM's SSEC. The stored program EDVAC, whose architecture Von Neumann had formalized, was still not yet running, and Von Neumann personally advised on adapting ENIAC to this mode of operation.
As I understand it, even after adaptation to "stored program" mode, the program was still configured rather than loaded and stored, but now configuration was done using the function table dials (essentially a dedicated dial for each program step) rather than patch cords, and was a lot more convenient. Punched cards could be used for reading/writing data, but not for programs.
It seems there was no BIOS because I/O was so primitive. Per configuration a punched card would be read into the "constant transmitter" unit, then one of the read numbers could be copied into one of the 20 accumulators. Or you could do the same in reverse to output data from the accumulators.
today at 8:07 PM
Man I didn't even realize that Quora was still around, let alone prominent people still answering questions on it. I deprioritized it in my Kagi searches months ago and even then I didn't notice that much of a change in the quality of my searches.
today at 8:51 PM
Yeah this is the first time in months if not years that I’m seeing the website.
today at 8:55 PM
Quora is such a gamble when it comes to accurate or relevant results. Either you get something incredibly insightful from someone with real experience or you get misinformation and stupid opinions. It's really only slightly helpful when I'm looking for subjective opinions or a personal perspective on some topic. It's very much a negative result when I'm looking for factual, verifiable information.
today at 9:45 PM
Some older people are on it, apparently, and some good experts among them too. Older folks often don't keep up with platform fashion. Some good older scientists even use academia.edu or researchgate...
Of course I'd prefer if he answered on a StackExchange site, tho I heard those are in decline too, but at least not enshittified like Quora.
today at 8:43 PM
Alan Kay answering questions on Quora. What a cool gift to the world!
This is one of the thing we lose as more and more of the conversations turn to people privately asking LLMs things, who do their best to scrape out answers from the existing info or make up a best guess. People are losing the ability to ask experts with real, unique knowledge and then share that knowledge with humanity.
today at 9:09 PM
The most surprising thing about this to me is Alan Kay answering questions on Quora.
today at 7:59 PM
www.quora.com Performing security verification This website uses a security service to protect against malicious bots. This page is displayed while the website verifies you are not a bot.
today at 8:03 PM
If you have too much adblock, as I do, you can never visit quora.com. The security check will just loop infinitely.
today at 8:36 PM
Maybe the times are changing. Went through with Adblock and vpn. No looping.
today at 8:28 PM
Funny. Just tested that because I'm always told: too complicated, nothing will work!
And got no check at all.
Edit: Maybe it depends on where you come from, or what they think you come from. Or using VPN. Wrong browser with insufficient base for uBo. uBo configured wrong. (Not?) using an ad-blocking DNS-Server, so that shit doesn't even make it to your local uBo?
Tested from Hamburg, Germany via private tunnel from my home in Colorado, which also works.