Alan Kay's old Quora answer on ENIAC's BIOS resurfaces on Hacker News
A years-old Quora response by computing pioneer Alan Kay to the question of whether ENIAC had a BIOS is circulating again after a fresh Hacker News submission.
What to know
- The story centers on a Quora answer by computing pioneer Alan Kay responding to the question 'Did the ENIAC have a BIOS?'
- The link resurfaced on Hacker News on September 27, 2026, gaining 101 points and 34 comments.
- The submission was also mirrored across an RSS aggregator and two automated Mastodon accounts that track Hacker News activity.
Alan Kay Computer scientist, author of the Quora answermidnightfish Hacker News submitter
How it unfolded 3 developments, newest first · click a bar or a number to jump articlesposts
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Mastodon bot hn100@social.lansky.name reposts the link
A second automated Mastodon account, which republishes Hacker News items, posted the same Quora link and HN discussion URL roughly ten hours later.
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Somewhat tangential, I've watched a bunch of videos on YouTube from @deramp5113 about the Altair 8800 and other early microcomputers, which feature a similar set of front panel switches for dialing in your initial program. One thing that's interesting to me, as someone who learned computing in the late 90s, is how much is expressed in octal…
2 more of the top 3 · 7 posts in this stretch
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The EDSAC's "boot ROM" consisted of a bank of large electro-meachanical "uniselector" rotary switches, hardwired to contain the 31 instructions ("initial orders") of the tape loader.Subsequent computers could have followed this "electro-mechanical ROM" approach, but I suppose it was rather bulky and inconvenient to change.You can see what the…
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> It seems a little strange that more advanced later machines like the original PDP-11 from 1970, couldn't "autostart" from ROM like that.Because the PDPs had magnetic core memory, so the bootloader, once toggled in, stayed in memory. The OS took care not to overwrite it.And in normal operation you wouldn't have to use it at all, you just switched…
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Mastodon bot hkrn@mstdn.social cross-posts the HN link
An automated Mastodon account mirrored the Hacker News submission and its discussion link shortly after the original post went up.
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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.¹The 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…
2 more of the top 3 · 5 posts in this stretch
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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…
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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…
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Hacker News Frontpage RSS syndicates the submission
The same submission appeared in an automated Hacker News Frontpage RSS feed, noting the linked HN discussion thread with an initial 5 points and 2 comments.
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background
midnightfish submits Alan Kay's Quora answer to Hacker News — A link to Alan Kay's Quora answer addressing whether the ENIAC had a BIOS was posted to Hacker News, reaching a score of 101 with 34 comments.
Also covered reported alongside — the timeline has no entry for these yet
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first by HN Best, 1d ago · also HN Frontpage
What people are saying 6 voices from 1 site · best of 12 · verbatim
- Yesterday
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So isn't the BIOS sort of an intermediary artifact?I think when CPM booted, there must have been some hardcoded disk firmware to get the boot sector into memory.The IBM PC bios was burned into the system.I think the boot process is multifaceted and can have as many stages.
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I don't remember any CP/M system with the BIOS part in ROM (and BDOS loaded from disk). It would be possible, of course, but every subsequent version of CP/M for that machine would need to be able to work with the "frozen" BIOS, and I'm not sure CP/M was designed thinking of mixing BIOS/BDOS versions.Saying that, I think the Epson PX-4 and PX-8…
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Kay nails it: the ENIAC 'BIOS' was literally a team of humans with patch cables. Makes you appreciate modern bootloaders.
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Yes that early pdp-11s had core memory, its contents survived power cycling. We'd hand toggle in the bootstrap into high ROM and start it, it would load whatever we were running from paper tape - unless you did something stupid that trashed that high memory you'd get to reuse the bootstrap over and overHaving said that the bootstrap was something…
- Sep 27
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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…
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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…